The Apology
Plato (428-347)
Written ca. 399-389 BCE Greece
“The Apology” (which means, simply, “defense”) is Plato’s account of the three speeches that Socrates gave at his trial in 399 B.C.E. At the age of 71, Socrates was charged by the prosecutors Anytus and Miletus with corruption of the youth of Athens, sophistry (fraudulent teaching practices), and heresy. We do not know exactly what the prosecution said in its presentation, because that has not been recorded for us, but it can be assumed that mention was made of some of Socrates’ students, like the politician Critias (one of the Thirty Tyrants) and the general Alcibiades, both of whom supported Athens’ rival Sparta and were regarded as traitors. It had therefore been rumored for some time that Socrates’ teachings were dangerous because they led men to rebel against the state. In his defense, Socrates argued that he only questioned authority in an effort to keep the state healthy and that he himself had nearly been the victim of Critias for refusing to do the bidding of the Thirty Tyrants.
“The Apology” consists of the following three speeches:
the defense proper: socrates answered the charges levelled against him.
the sentencing plea: having been found guilty, socrates was expected to request exile, but he refused to do so.
socrates’s farewell to Athens: After being sentenced to death, socrates spoke to both his detractors and his supporters.
Plato, Socrates’ faithful student, was an attendant at both his trial and his subsequent execution, and he gifted to us “The Apology” which stands over two millennia later as a monument to freedom and justice and truth.
Questions to consider while reading this selection:
What is Socrates attitude toward the trial and his prosecutors? What about the judges?
You will notice as you read that Socrates has to ask the 500 judges to settle down periodically. What is that the audience is feeling? Are they cheering or booing him? How can you tell? Does he agitate them on purpose?
Some have said that Socrates behaves arrogantly. Do you agree? Why or why not?
Looking at “The Apology” as Socrates’ last chance to teach the Athenians something, what do you think he tried to teach them?
Written by Rhonda L. Kelley
The Apology of Socrates
License: CC BY-SA 4.0
Socrates, translated by Henry Cary
Edited, annotated, and compiled by Rhonda L. Kelley
The Defense77
“I am Not Eloquent”
I know not, O Athenians!78 how far you have been influenced by my accusers79 for my part, in listening to them I almost forgot myself, so plausible were their arguments however, so to speak, they have said nothing true. But of the many falsehoods which they uttered I wondered at one of them especially, that in which they said that you ought to be on your guard lest you should be deceived by me, as being eloquent in speech. For that they are not ashamed of being forthwith convicted by me in fact, when I shall show that I am not by any means eloquent, this seemed to me the most shameless thing in them, unless indeed they call him eloquent who speaks the truth. For, if they mean this, then I would allow that I am an orator, but not after their fashion80 for they, as I affirm, have said nothing true, but from me you shall hear the whole truth. Not indeed, Athenians, arguments highly wrought, as theirs were, with choice phrases and expressions, nor adorned, but you shall hear a speech uttered without premeditation in such words as first present themselves.81 For I am confident that what I say will be just, and let none of you expect otherwise, for surely it would not become my time of life to come before you like a youth with a got up82 speech. Above all things, therefore, I beg and implore this of you, O Athenians! if you hear me defending myself in the same language as that in which I am accustomed to speak both in the forum83 at the counters, where many of you have heard me, and elsewhere, not to be surprised or disturbed84 on this account. For the case is this: I now for the first time come before a court of justice, though more than seventy years old; I am therefore utterly a stranger to the language here. As, then, if I were really a stranger, you would have pardoned me if I spoke in the language and the manner in which I had been educated, so now I ask this of you as an act of justice, as it appears to me, to disregard the manner of my speech, for perhaps it may be somewhat worse, and perhaps better, and to consider this only, and to give your attention to this, whether I speak what is just or not; for this is the virtue of a judge, but of an orator to speak the truth.
“My First Accusers”
2. First, then, O Athenians! I am right in defending myself against the first false accusations alleged against me, and my first accusers, and then against the latest accusations, and the latest accusers. For many have been accusers of me to you, and for many years, who have asserted nothing true, of whom I am more afraid than of Anytus85 and his party, although they too are formidable; but those are still more formidable, Athenians, who, laying hold of many of you from childhood, have persuaded you, and accused me of what is not true: “that there is one Socrates, a wise man, who occupies himself about celestial matters, and has explored everything under the earth,86 and makes the worse appear the better reason.”87 Those, O Athenians! who have spread abroad this report are my formidable accusers; for they who hear them think that such as search into these things do not believe that there are gods. In the next place, these accusers are numerous, and have accused me now for a long time; moreover, they said these things to you at that time of life in which you were most credulous, when you were boys and some of you youths, and they accused me altogether in my absence, when there was no one to defend me. But the most unreasonable thing of all is, that it is not possible to learn and mention their names, except that one of them happens to be a comic poet.88 Such, however, as, influenced by envy and calumny, have persuaded you, and those who, being themselves persuaded, have persuaded others, all these are most difficult to deal with; for it is not possible to bring any of them forward here, nor to confute any;89 but it is altogether necessary to fight, as it were with a shadow, in making my defense, and to convict when there is no one to answer. Consider, therefore, as I have said, that my accusers are twofold, some who have lately accused me, and others long since, whom I have made mention of; and believe that I ought to defend myself against these first; for you heard them accusing me first, and much more than these last.
Well. I must make my defense, then, O Athenians! and endeavor in this so short a space of time to remove from your minds the calumny which you have long entertained. I wish, indeed, it might be so, if it were at all better both for you and me, and that in making my defense I could affect something more advantageous still: I think, however, that it will be difficult, and I am not entirely ignorant what the difficulty is. Nevertheless, let this turn out as may be pleasing to God, I must obey the law and make my defense.
3. Let us, then, repeat from the beginning what the accusation is from which the calumny against me has arisen, and relying on which Meletus has preferred this indictment against me. Well. What, then, do they90 who charge me say in their charge? For it is necessary to read their deposition as of public accusers. “Socrates acts wickedly, and is criminally curious in searching into things under the earth, and in the heavens,91 and in making the worse appear the better cause,92 and in teaching these same things to others.”93 Such is the accusation: for such things you have yourselves seen in the comedy of Aristophanes,94 one Socrates there carried about, saying that he walks in the air,95 and acting many other buffooneries, of which I understand nothing whatever. Nor do I say this as disparaging such a science, if there be any one skilled in such things, only let me not be prosecuted by Meletus on a charge of this kind; but I say it, O Athenians! because I have nothing to do with such matters. And I call upon most of you as witnesses of this, and require you to inform and tell each other, as many of you as have ever heard me conversing; and there are many such among you.96 Therefore tell each other, if any one of you has ever heard me conversing little or much on such subjects.97 And from this you will know that other things also, which the multitude assert of me, are of a similar nature.
4. However not one of these things is true; nor, if you have heard from any one that I attempt to teach men, and require payment,98 is this true. Though this, indeed, appears to me to be an honorable thing, if one should be able to instruct men, like Gorgias of Leontium,99 and Prodicus of Ceos,100 and Hippias of Elis.101 For each of these, O Athenians! is able, by going through the several cities, to persuade the young men, who can attach themselves gratuitously to such of their own fellow-citizens as they please, to abandon their fellow-citizens and associate with them, giving them money and thanks besides. There is also another wise man here, a Parian, who, I hear, is staying in the city. For I happened to visit a person who spends more money on the sophists than all others together: I mean Callias, son of Hipponicus. I therefore asked him, for he has two sons, “Callias,” I said, “if your two sons were colts or calves, we should have had to choose a master for them, and hire a person who would make them excel in such qualities as belong to their nature; and he would have been a groom or an agricultural laborer. But now, since your sons are men, what master do you intend to choose for them? Who is there skilled in the qualities that become a man and a citizen? For I suppose you must have considered this, since you have sons. Is there any one,” I said, “or not?” “Certainly,” he answered. “Who is he?” said I, “and whence does he come? and on what terms does he teach?” He replied, “Evenus the Parian, Socrates, for five minæ.”102 And I deemed Evenus happy, if he really possesses this art, and teaches admirably.103 And I too should think highly of myself, and be very proud, if I possessed this knowledge, but I possess it not, O Athenians.
“Why I Am Called Wise”
5. Perhaps, one of you may now object: “But, Socrates, what have you done, then? Whence have these calumnies104 against you arisen? For surely if you had not busied yourself more than others, such a report and story would never have got abroad, unless you had done something different from what most men do. Tell us, therefore, what it is, that we may not pass a hasty judgment on you.” He who speaks thus appears to me to speak justly, and I will endeavor to show you what it is that has occasioned me this character and imputation. Listen, then: to some of you perhaps I shall appear to jest, yet be assured that I shall tell you the whole truth. For I, O Athenians! have acquired this character through nothing else than a certain wisdom. Of what kind, then, is this wisdom? Perhaps it is merely human wisdom. For in this, in truth, I appear to be wise. They probably, whom I have just now mentioned, possessed a wisdom more than human, otherwise I know not what to say about it; for I am not acquainted with it, and whosoever says I am, speaks falsely, and for the purpose of calumniating105 me. But, O Athenians! do not cry out against me, even though I should seem to you to speak somewhat arrogantly. For the account which I am going to give you is not my own; but I shall refer to an authority whom you will deem worthy of credit. For I shall adduce to you the god at Delphi106 as a witness of my wisdom, if I have any, and of what it is. You doubtless know Chærepho: he was my associate from youth, and the associate of most of you; he accompanied you in your late exile, and returned with you.107 You know, then, what kind of a man Chærepho was, how earnest in whatever he undertook. Having once gone to Delphi, he ventured to make the following inquiry of the oracle (and, as I said, O Athenians! do not cry out), for he asked if there was any one wiser than I. The Pythian [oracle] thereupon answered that there was not one wiser; and of this, his brother here will give you proofs, since he himself is dead.
“The Origin of My Method”
6. Consider, then, why I mention these things: it is because I am going to show you whence the calumny against me arose. For when I heard this, I reasoned thus with myself, What does the god mean? What enigma is this? For I am not conscious to myself that I am wise, either much or little. What, then, does he108 mean by saying that I am the wisest? For assuredly he does not speak falsely: that he could not do. And for a long time I was in doubt what he meant; afterward, with considerable difficulty, I had recourse to the following method of searching out his meaning. I went to one of those who have the character of being wise, thinking that there, if anywhere, I should confute109 the oracle, and show in answer to the response that this man is wiser than I, though you110 affirmed that I was the wisest. Having, then, examined this man (for there is no occasion to mention his name; he was, however, one of our great politicians, in examining whom I felt as I proceed to describe, O Athenians!), having fallen into conversation with him, this man appeared to be wise in the opinion of most other men, and especially in his own opinion, though in fact he was not so. I thereupon endeavored to show him that he fancied himself to be wise, but really was not. Hence I became odious,111 both to him and to many others who were present. When I left him, I reasoned thus with myself: I am wiser than this man, for neither of us appears to know anything great and good; but he fancies he knows something, although he knows nothing; whereas I, as I do not know anything, so I do not fancy I do. In this trifling particular, then, I appear to be wiser than he, because I do not fancy I know what I do not know. After that I went to another who was thought to be wiser than the former, and formed the very same opinion. Hence I became odious to him and to many others.
7. After this I went to others in turn, perceiving indeed, and grieving and alarmed, that I was making myself odious; however, it appeared necessary to regard the oracle of the god as of the greatest moment, and that, in order to discover its meaning, I must go to all who had the reputation of possessing any knowledge. And by the god, O Athenians! for I must tell you the truth, I came to some such conclusion as this: those who bore the highest reputation appeared to me to be most deficient, in my researches in obedience to the god, and others who were considered inferior more nearly approaching to the possession of understanding. But I must relate to you my wandering, and the labors which I underwent, in order that the oracle might prove incontrovertible. For after the politicians I went to the poets, as well the tragic as the dithyrambic and others, expecting that here I should in very fact find myself more ignorant than they. Taking up, therefore, some of their poems, which appeared to me most elaborately finished, I questioned them as to their meaning, that at the same time I might learn something from them. I am ashamed, O Athenians! to tell you the truth; however, it must be told. For, in a word, almost all who were present could have given a better account of them than those by whom they had been composed. I soon discovered this, therefore, with regard to the poets, that they do not affect their object by wisdom, but by a certain natural inspiration, and under the influence of enthusiasm, like prophets and seers; for these also say many fine things, but they understand nothing that they say. The poets appeared to me to be affected in a similar manner; and at the same time I perceived that they considered themselves, on account of their poetry, to be the wisest of men in other things, in which they were not. I left them, therefore, under the persuasion that I was superior to them, in the same way that I was to the politicians.
8. At last, therefore, I went to the artisans.112 For I was conscious to myself that I knew scarcely anything, but I was sure that I should find them possessed of much beautiful knowledge. And in this I was not deceived; for they knew things which I did not, and in this respect they were wiser than I. But, O Athenians! even the best workmen appeared to me to have fallen into the same error as the poets; for each, because he excelled in the practice of his art, thought that he was very wise in other most important matters, and this mistake of theirs obscured the wisdom that they really possessed. I therefore asked myself, in behalf of the oracle, whether I should prefer to continue as I am, possessing none, either of their wisdom or their ignorance, or to have both as they have. I answered, therefore, to myself and to the oracle, that it was better for me to continue as I am.
9. From this investigation, then, O Athenians! many enmities have arisen against me, and those the most grievous and severe, so that many calumnies have sprung from them, and among them this appellation of being wise; for those who are from time to time present think that I am wise in those things, with respect to which I expose the ignorance of others. The god, however, O Athenians! appears to be really wise, and to mean this by his oracle: that human wisdom is worth little or nothing; and it is clear that he did not say this to Socrates, but made use of my name, putting me forward as an example, as if he had said, that man is the wisest among you, who, like Socrates, knows that he is in reality worth nothing with respect to wisdom. Still, therefore, I go about and search and inquire into these things, in obedience to the god, both among citizens and strangers, if I think any one of them is wise; and when he appears to me not to be so, I take the part of the god, and show that he is not wise. And, in consequence of this occupation, I have no leisure to attend in any considerable degree to the affairs of the state or my own; but I am in the greatest poverty through my devotion to the service of the god.
10. In addition to this, young men, who have much leisure and belong to the wealthiest families, following me of their own accord, take great delight in hearing men put to the test, and often imitate me, and themselves attempt to put others to the test; and then, I think, they find a great abundance of men who fancy they know something, although they know little or nothing. Hence those who are put to the test by them are angry with me, and not with them, and say that “there is one Socrates, a most pestilent fellow, who corrupts the youth.” And when any one asks them by doing or teaching what, they have nothing to say, for they do not know; but, that they may not seem to be at a loss, they say such things as are ready at hand against all philosophers: “that he searches into things in heaven and things under the earth, that he does not believe there are gods, and that he makes the worse appear the better reason.” For they would not, I think, be willing to tell the truth that they have been detected in pretending to possess knowledge, whereas they know nothing. Therefore, I think, being ambitious and vehement and numerous, and speaking systematically and persuasively about me, they have filled your ears, for a long time and diligently calumniating me. From among these, Meletus, Anytus, and Lycon113 have attacked me; Meletus being angry on account of the poets, Anytus on account of the artisans and politicians, and Lycon on account of the rhetoricians.114 So that, as I said in the beginning, I should wonder if I were able in so short a time to remove from your minds a calumny that has prevailed so long. This, O Athenians! is the truth; and I speak it without concealing or disguising anything from you, much or little; though I very well know that by so doing I shall expose myself to odium. This, however, is a proof that I speak the truth, and that this is the nature of the calumny against me, and that these are its causes. And if you will investigate the matter, either now or hereafter, you will find it to be so.
“Tell Me Meletus…”
11. With respect, then, to the charges which my first accusers have alleged against me, let this be a sufficient apology115 to you. To Meletus, that good and patriotic man, as he says, and to my later accusers, I will next endeavor to give an answer; and here, again, as there are different accusers, let us take up their deposition. It is pretty much as follows: “Socrates,” it says, “acts unjustly in corrupting the youth, and in not believing in those gods in whom the city believes, but in other strange divinities.”116 Such is the accusation; let us examine each particular of it. It says that I act unjustly in corrupting the youth. But I, O Athenians! say that Meletus117 acts unjustly, because he jests on serious subjects, rashly putting men upon trial, under pretense of being zealous and solicitous about things in which he never at any time took any concern. But that this is the case I will endeavor to prove to you.
12. Come, then, Meletus, tell me, do you not consider it of the greatest importance that the youth should be made as virtuous as possible?
Mel. I do.
Socr. Well, now, tell the judges who it is that makes them better, for it is evident that you know, since it concerns you so much; for, having detected me in corrupting them, as you say, you have cited me here, and accused me: come, then, say, and inform the judges who it is that makes them better.
[Meletus does not answer.]
Do you see, Meletus, that you are silent, and have nothing to say? But does it not appear to you to be disgraceful, and a sufficient proof of what I say, that you never took any concern about the matter? But tell me, friend, who makes them better?
Mel. The laws.
Socr. I do not ask this, most excellent sir, but what man, who surely must first know this very thing, the laws?
Mel. These, Socrates, the judges.118
Socr. How say you, Meletus? Are these able to instruct the youth, and make them better?
Mel. Certainly.
Socr. All [of the judges], or some of them, and others not?
Mel. All.
Socr. You say well, by Juno! and have found a great abundance of those that confer benefit. But what further? Can these hearers119 make them better, or not?
Mel. They, too, can.
Socr. And what of the senators?
Mel. The senators, also.
Socr. But, Meletus, do those who attend the public assemblies corrupt the younger men? or do they all make them better?
Mel. They too.
Socr. All the Athenians, therefore, as it seems, make them honorable and good, except me; but I alone corrupt them. Do you say so?
Mel. I do assert this very thing.
Socr. You charge me with great ill-fortune. But answer me: does it appear to you to be the same, with respect to horses? Do all men make them better, and is there only some one that spoils them? or does quite the contrary of this take place? Is there some one person who can make them better, or very few; that is, the trainers? But if the generality of men should meddle with and make use of horses, do they spoil them? Is not this the case, Meletus, both with respect to horses and all other animals? It certainly is so, whether you and Anytus deny it or not. For it would be a great good-fortune for the youth if only one person corrupted, and the rest benefited them. However, Meletus, you have sufficiently shown that you never bestowed any care upon youth; and you clearly evince your own negligence, in that you have never paid any attention to the things with respect to which you accuse me.
13. Tell us further, Meletus, in the name of Zeus, whether is it better to dwell with good or bad citizens?
[Meletus does not respond.]
Answer, my friend; for I ask you nothing difficult. Do not the bad work some evil to those that are continually near them, but the good some good?
Mel. Certainly.
Socr. Is there any one that wishes to be injured rather than benefited by his associates?
[Meletus does not respond.]
Answer, good man; for the law requires you to answer. Is there any one who wishes to be injured?
Mel. No, surely.
Socr. Come, then, whether do you accuse me here, as one that corrupts the youth, and makes them more depraved, designedly or undesignedly?120
Mel. Designedly, I say.
Socr. What, then, Meletus, are you at your time of life so much wiser than I at my time of life, as to know that the evil are always working some evil to those that are most near to them, and the good some good; but I have arrived at such a pitch of ignorance as not to know that if I make any one of my associates depraved, I shall be in danger of receiving some evil from him; and yet I designedly bring about this so great evil, as you say? In this I cannot believe you, Meletus, nor do I think would any other man in the world. But either I do not corrupt the youth, or, if I do corrupt them, I do it undesignedly: so that in both cases you speak falsely. But if I corrupt them undesignedly, for such involuntary offenses it is not usual to accuse one here, but to take one apart, and teach and admonish one. For it is evident that if I am taught, I shall cease doing what I do undesignedly. But you shunned me, and were not willing to associate with and instruct me; but you accuse me here, where it is usual to accuse those who need punishment, and not instruction.121
14. Thus, then, O Athenians! this now is clear that I have said; that Meletus never paid any attention to these matters, much or little. However, tell us, Meletus, how you say I corrupt the youth? Is it not evidently, according to the indictment which you have preferred, by teaching them not to believe in the gods in whom the city believes, but in other strange deities? Do you not say that, by teaching these things, I corrupt the youth?
Mel. Certainly I do say so.
Socr. By those very gods, therefore, Meletus, of whom the discussion now is, speak still more clearly both to me and to these men. For I cannot understand whether you say that I teach them to believe that there are certain gods (and in that case I do believe that there are gods, and am not altogether an atheist, nor in this respect to blame), not, however, those which the city believes in, but others; and this it is that you accuse me of, that I introduce others. Or do you say outright that I do not myself believe that there are gods, and that I teach others the same?
Mel. I say this: that you do not believe in any gods at all.
Socr. O wonderful Meletus, how come you to say this? Do I not, then, like the rest of mankind, believe that the sun and moon are gods?
Mel. No, by Zeus, O judges! for he says that the sun is a stone, and the moon an earth.122
Socr. You fancy that you are accusing Anaxagoras,123 my dear Meletus, and thus you put a slight on124 these men, and suppose them to be so illiterate as not to know that the books of Anaxagoras of Clazomene are full of such assertions. And the young, moreover, learn these things from me? Things which they might purchase for a drachma, at most, in the orchestra, and so ridicule Socrates, if he pretended they were his own, especially since they are so absurd? I ask then, by Zeus, do I appear to you to believe that there is no god?
Mel. No, by Zeus, none whatever.
Socr. You say what is incredible, Meletus, and that, as appears to me, even to yourself. For this man, O Athenians! appears to me to be very insolent and intemperate and to have preferred this indictment through downright insolence, intemperance, and wantonness. For he seems, as it were, to have composed an enigma for the purpose of making an experiment: “Will Socrates the Wise know that I am jesting, and contradict myself, or shall I deceive him and all who hear me?” For, in my opinion, he clearly contradicts himself in the indictment, as if he should say, “Socrates is guilty of wrong in not believing that there are gods, and in believing that there are gods.” And this, surely, is the act of one who is trifling.
15. Consider with me now, Athenians, in what respect he appears to me to say so. And do you, Meletus, answer me; and do ye,125 as I besought you at the outset, remember not to make an uproar if I speak after my usual manner.
Is there any man, Meletus, who believes that there are human affairs, but does not believe that there are men? Let him answer, judges, and not make so much noise.126 Is there any one who does not believe that there are horses, but that there are things pertaining to horses? or who does not believe that there are pipers, but that there are things pertaining to pipes?
[Meletus does not respond.]
There is not, O best of men! for since you are not willing to answer, I say it to you and to all here present. But answer to this at least: is there any one who believes that there are things relating to daimons,127 but does not believe that there are daimons?
Mel. There is not.
Socr. How obliging you are in having hardly answered; though compelled by these judges! You assert, then, that I do believe and teach things relating to daimons, whether they be new or old;128 therefore, according to your admission, I do believe in things relating to daimons, and this you have sworn in the bill of indictment. If, then, I believe in things relating to daimons, there is surely an absolute necessity that I should believe that there are daimons. Is it not so?
[Meletus does not respond.]
It is. For I suppose you to assent, since you do not answer. But with respect to daimons, do we not allow that they are gods, or the children of gods? Do you admit this or not?
Mel. Certainly.
Socr. Since, then, I allow that there are daimons, as you admit, if daimons are a kind of gods, this is the point in which I say you speak enigmatically and divert yourself in saying that I do not allow there are gods, and again that I do allow there are, since I allow that there are daimons? But if daimons are the children of gods, spurious ones, either from nymphs or any others, of whom they are reported to be, what man can think that there are sons of gods, and yet that there are not gods? For it would be just as absurd as if any one should think that there are mules, the offspring of horses and asses, but should not think there are horses and asses. However, Meletus, it cannot be otherwise than that you have preferred this indictment for the purpose of trying me, or because you were at a loss what real crime to allege against me; for that you should persuade any man who has the smallest degree of sense that the same person can think that there are things relating to daimons and to gods, and yet that there are neither daimons, nor gods, nor heroes, is utterly impossible.
“I Cannot Abandon My Post”
16. That I am not guilty, then, O Athenians! according to the indictment of Meletus, appears to me not to require a lengthened defense; but what I have said is sufficient. And as to what I said at the beginning, that there is a great enmity toward me among the multitude, be assured it is true. And this it is which will condemn me, if I am condemned, not Meletus, nor Anytus, but the calumny and envy of the multitude, which have already condemned many others, and those good men, and will, I think, condemn others also; for there is no danger that it will stop with me.
Perhaps, however, someone may say, “Are you not ashamed, Socrates, to have pursued a study from which you are now in danger of dying?” To such a person I should answer with good reason, you do not say well, friend, if you think that a man, who is even of the least value, ought to take into the account the risk of life or death, and ought not to consider that he is alone when he performs any action, whether he is acting justly or unjustly, and the part of a good man or bad man. For, according to your reasoning, all those demi-gods129 that died at Troy130 would be vile characters, as well as the son of Thetis,131 who so far despised danger in comparison of submitting to disgrace, that when his mother, who was a goddess, spoke to him, in his impatience to kill Hector, something to this effect, as I think, “My son, if you revenge the death of your friend Patroclus, and slay Hector, you will yourself die, for,” she said, “death awaits you immediately after Hector;” but he, on hearing this, despised death and danger, and dreading much more to live as a coward, and not avenge his friend, said, “May I die immediately when I have inflicted punishment on the guilty, that I may not stay here an object of ridicule, by the curved ships, a burden to the ground?” Do you think that he cared for death and danger? For thus it is, O Athenians! in truth: wherever any one has posted himself, either thinking it to be better, or has been posted by his chief, there, as it appears to me, he ought to remain and meet danger, taking no account either of death or anything else in comparison with disgrace.
17. I then should be acting strangely, O Athenians! if, when the generals whom you chose to command me assigned me my post at Potidaea, at Amphipolis, and at Delium,132 I then remained where they posted me, like any other person, and encountered the danger of death; but when the deity,133 as I thought and believed, assigned it as my duty to pass my life in the study of philosophy, and examining myself and others, I should on that occasion, through fear of death or anything else whatsoever, desert my post, strange indeed would it be; and then, in truth, any one might justly bring me to trial, and accuse me of not believing in the gods, from disobeying the oracle, fearing death, and thinking myself to be wise when I am not. For to fear death, O Athenians! is nothing else than to appear to be wise, without being so; for it is to appear to know what one does not know. For no one knows but that death is the greatest of all good to man; but men fear it, as if they well knew that it is the greatest of evils. And how is not this the most reprehensible ignorance, to think that one knows what one does not know? But I, O Athenians! in this, perhaps, differ from most men; and if I should say that I am in anything wiser than another, it would be in this, that not having a competent knowledge of the things in Hades,134 I also think that I have not such knowledge.  I shall never, therefore, fear or shun things which, for aught I know, maybe good, before evils which I know to be evils. So that, even if you should now dismiss me, not yielding to the instances of Anytus, who said that either I should not appear here at all, or that, if I did appear, it was impossible not to put me to death, telling you that if I escaped, your sons, studying what Socrates teaches, would all be utterly corrupted; if you should address me thus, “Socrates, we shall not now yield to Anytus, but dismiss you, on this condition, however, that you no longer persevere in your researches nor study philosophy; and if hereafter you are detected in so doing, you shall die”—if, as I said, you should dismiss, me on these terms, I should say to you, “O Athenians! I honor and love you; but I shall obey God rather than you; and so long as I breathe and am able, I shall not cease studying philosophy, and exhorting you and warning any one of you I may happen to meet, saying, as I have been accustomed to do: ‘O best of men! seeing you are an Athenian, of a city the most powerful and most renowned for wisdom and strength, are you not ashamed of being careful for riches, how you may acquire them in greatest abundance, and for glory, and honor, but care not nor take any thought for wisdom and truth, and for your soul, how it maybe made most perfect?’“ And if any one of you should question my assertion, and affirm that he does care for these things, I shall not at once let him go, nor depart, but I shall question him, sift and prove him. And if he should appear to me not to possess virtue, but to pretend that he does, I shall reproach him for that he sets the least value on things of the greatest worth, but the highest on things that are worthless. Thus I shall act to all whom I meet, both young and old, stranger and citizen, but rather to you, my fellow-citizens, because ye are more nearly allied to me. For be well assured, this the deity commands. And I think that no greater good has ever befallen you in the city than my zeal for the service of the god. For I go about doing nothing else than persuading you, both young and old, to take no care either for the body, or for riches, prior to or so much as for the soul, how it may be made most perfect, telling you that virtue does not spring from riches, but riches and all other human blessings, both private and public, from virtue. If, then, by saying these things, I corrupt the youth, these things must be mischievous; but if any one says that I speak other things than these, he misleads you. Therefore I must say, O Athenians! either yield to Anytus, or do not, either dismiss me or not, since I shall not act otherwise, even though I must die many deaths.
“I Am God’s Gift To Athens”
18. Murmur not, O Athenians! but continue to attend to my request, not to murmur at what I say, but to listen, for, as I think, you will derive benefit from listening. For I am going to say other things to you, at which, perhaps, you will raise a clamor; but on no account do so. Be well assured, then, if you put me to death, being such a man as I say I am, you will not injure me more than yourselves. For neither will Meletus nor Anytus harm me; nor have they the power; for I do not think that it is possible for a better man to be injured by a worse. He may perhaps have me condemned to death, or banished, or deprived of civil rights; and he or others may perhaps consider these as mighty evils; I, however, do not consider them so, but that it is much more so to do what he is now doing, to endeavor to put a man to death unjustly. Now, therefore, O Athenians! I am far from making a defense on my behalf, as any one might think, but I do so on your own behalf, lest by condemning me you should offend at all with respect to the gift of the deity to you. For, if you should put me to death, you will not easily find such another, though it may be ridiculous to say so, altogether attached by the deity to this city as to a powerful and generous horse, somewhat sluggish from his size, and requiring to be roused by a gad-fly; so the deity appears to have united me, being such a person as I am, to the city, that I may rouse you, and persuade and reprove every one of you, nor ever cease besetting you throughout the whole day. Such another man, O Athenians! will not easily be found; therefore, if you will take my advice, you will spare me. But you, perhaps, being irritated like drowsy persons who are roused from sleep, will strike me, and, yielding to Anytus, will unthinkingly condemn me to death; and then you will pass the rest of your life in sleep, unless the deity, caring for you, should send someone else to you. But that I am a person who has been given by the deity to this city, you may discern from hence; for it is not like the ordinary conduct of men, that I should have neglected all my own affairs, and suffered my private interest to be neglected for so many years, and that I should constantly attend to your concerns, addressing myself to each of you separately, like a father, or elder brother, persuading you to the pursuit of virtue. And if I had derived any profit from this course, and had received pay for my exhortations, there would have been some reason for my conduct; but now you see yourselves that my accusers, who have so shamelessly calumniated me in everything else, have not had the impudence to charge me with this, and to bring witnesses to prove that I ever either exacted or demanded any reward. And I think I produce a sufficient proof that I speak the truth, namely, my poverty.
“Why I Teach But Do Not Engage In Political Life”
19. Perhaps, however, it may appear absurd that I, going about, thus advise you in private and make myself busy, but never venture to present myself in public before your assemblies and give advice to the city. The cause of this is that which you have often and in many places heard me mention; because I am moved by a certain divine and spiritual influence, which also Meletus, through mockery, has set out in the indictment. This began with me from childhood, being a kind of voice which, when present, always diverts me from what I am about to do, but never urges me on.135 This it is which opposed my meddling in public politics; and it appears to me to have opposed me very properly. For be well assured, O Athenians! if I had long since attempted to intermeddle with politics, I should have perished long ago, and should not have at all benefited you or myself. And be not angry with me for speaking the truth. For it is not possible that any man should be safe who sincerely opposes either you, or any other multitude, and who prevents many unjust and illegal actions from being committed in a city; but it is necessary that he who in earnest contends for justice, if he will be safe for but a short time, should live privately, and take no part in public affairs.
20. I will give you strong proofs of this, not words, but what you value, facts. Hear, then, what has happened to me, that you may know that I would not yield to any one contrary to what is just, through fear of death, at the same time by not yielding I must perish. I shall tell you what will be displeasing and wearisome, yet true. For I, O Athenians! never bore any other magisterial office in the city, but have been a senator,136 and our Antiochean tribe happened to supply the Prytanes when you chose to condemn in a body the ten generals who had not taken off those that perished in the sea-fight, in violation of the law, as you afterward all thought. At that time I alone of the Prytanes opposed your doing anything contrary to the laws, and I voted against you; and when the orators were ready to denounce me, and to carry me before a magistrate, and you urged and cheered them on, I thought I ought rather to meet the danger with law and justice on my side, than through fear of imprisonment or death, to take part with you in your unjust designs. And this happened while the city was governed by a democracy. But when it became an oligarchy, the Thirty,137 having sent for me with four others to the Tholus, ordered us to bring Leon the Salaminian from Salamis, that he might be put to death; and they gave many similar orders to many others, wishing to involve as many as they could in guilt. Then, however, I showed, not in word but in deed, that I did not care for death, if the expression be not too rude, in the smallest degree; but that all my care was to do nothing unjust or unholy. For that government, strong as it was, did not so overawe me as to make me commit an unjust action; but when we came out from the Tholus, the four went to Salamis, and brought back Leon; but I went away home. And perhaps for this I should have been put to death, if that government had not been speedily broken up. And of this you can have many witnesses.
21. Do you think, then, that I should have survived so many years if I had engaged in public affairs, and, acting as becomes a good man, had aided the cause of justice, and, as I ought, had deemed this of the highest importance? Far from it, O Athenians! nor would any other man have done so. But I, through the whole of my life, if I have done anything in public, shall be found to be a man, and the very same in private, who has never made a concession to any one contrary to justice, neither to any other, nor to any one of these whom my calumniators say are my disciples. I, however, was never the preceptor of any one; but if any one desired to hear me speaking, and to see me busied about my own mission, whether he were young or old, I never refused him. Nor do I discourse when I receive money, and not when I do not receive any, but I allow both rich and poor alike to question me, and, if any one wishes it, to answer me and hear what I have to say. And for these, whether any one proves to be a good man or not, I cannot justly be responsible, because I never either promised them any instruction or taught them at all. But if any one says that he has ever learned or heard anything from me in private which all others have not, be well assured that he does not speak the truth.
22. But why do some delight to spend so long a time with me? Ye have heard, O Athenians! I have told you the whole truth, that they delight to hear those closely questioned who think that they are wise but are not; for this is by no means disagreeable. But this duty, as I say, has been enjoined me by the deity, by oracles, by dreams, and by every mode by which any other divine decree has ever enjoined anything to man to do. These things, O Athenians! are both true, and easily confuted if not true. For if I am now corrupting some of the youths, and have already corrupted others, it were fitting, surely, that if any of them, having become advanced in life, had discovered that I gave them bad advice when they were young, they should now rise up against me, accuse me, and have me punished; or if they were themselves unwilling to do this, some of their kindred, their fathers, or brothers, or other relatives, if their kinsman have ever sustained any damage from me, should now call it to mind. Many of them, however, are here present, whom I see: first, Crito, my contemporary and fellow-burgher,138 father of this Critobulus; then Lysanias of Sphettus, father of this Æschines; again, Antiphon of Cephisus, father of Epigenes. There are those others, too, whose brothers maintained the same intimacy with me, namely, Nicostratus, son of Theodotus, brother of Theodotus (Theodotus indeed is dead, so that he could not deprecate his brother’s proceedings), and Paralus here, son of Demodocus, whose brother was Theages; and Adimantus, son of Ariston, whose brother is this Plato;139 and Æantodorus, whose brother is this Apollodorus.140 I could also mention many others to you, some one of whom certainly Meletus ought to have adduced in his speech as a witness. If, however, he then forgot to do so, let him now adduce them; I give him leave to do so, and let him say it, if he has anything of the kind to allege. But, quite contrary to this, you will find, O Athenians! all ready to assist me, who have corrupted and injured their relatives,141 as Meletus and Anytus say. For those who have been themselves corrupted might perhaps have some reason for assisting me; but those who have not been corrupted, men now advanced in life, their relatives, what other reason can they have for assisting me, except that right and just one, that they know that Meletus speaks falsely, and that I speak the truth.
“Why I Will Not Beg For Mercy”
23. Well, then, Athenians, these are pretty much the things I have to say in my defense, and others perhaps of the same kind. Perhaps, however, some among you will be indignant on recollecting his own case, if he, when engaged in a cause far less than this, implored and besought the judges with many tears, bringing forward his children in order that he might excite their utmost compassion, and many others of his relatives and friends, whereas I do none of these things, although I may appear to be incurring the extremity of danger. Perhaps, therefore, someone, taking notice of this, may become more determined against me, and, being enraged at this very conduct of mine, may give his vote under the influence of anger. If, then, any one of you is thus affected (I do not, however, suppose that there is, but if there should be), I think I may reasonably say to him: “I, too, O best of men, have relatives; for, to make use of that saying of Homer, I am not sprung from an oak, nor from a rock, but from men,142 so that I, too, O Athenians! have relatives, and three sons, one now grown up, and two boys: I shall not, however, bring any one of them forward and implore you to acquit me.” Why, then, shall I not do this? Not from contumacy,143 O Athenians! nor disrespect toward you. Whether or not I am undaunted at the prospect of death is another question; but, out of regard to my own character, and yours, and that of the whole city, it does not appear to me to be honorable that I should do anything of this kind at my age, and with the reputation I have, whether true or false. For it is commonly agreed that Socrates in some respects excels the generality of men. If, then, those among you who appear to excel either in wisdom, or fortitude, or any other virtue whatsoever, should act in such a manner as I have often seen some when they have been brought to trial, it would be shameful, who appearing indeed to be something, have conducted themselves in a surprising manner, as thinking they should suffer something dreadful by dying, and as if they would be immortal if you did not put them to death. Such men appear to me to bring disgrace on the city, so that any stranger might suppose that such of the Athenians as excel in virtue, and whom they themselves choose in preference to themselves for magistracies and other honors, are in no respect superior to women. For these things, O Athenians! neither ought we to do who have attained to any height of reputation, nor, should we do them, ought you to suffer us; but you should make this manifest, that you will much rather condemn him who introduces these piteous dramas, and makes the city ridiculous, than him who quietly awaits your decision.
24. But, reputation apart, O Athenians! it does not appear to me to be right to entreat a judge, or to escape by entreaty; but one ought to inform and persuade him. For a judge does not sit for the purpose of administering justice out of favor, but that he may judge rightly, and he is sworn not to show favor to whom he pleases, but that he will decide according to the laws. It is, therefore, right that neither should we accustom you, nor should you accustom yourselves, to violate your oaths; for in so doing neither of us would act righteously. Think not then, O Athenians! that I ought to adopt such a course toward you as I neither consider honorable, nor just, nor holy, as well, by Zeus! on any other occasion, and now especially when I am accused of impiety by this Meletus. For clearly, if I should persuade you, and by my entreaties should put a constraint on you who are bound by an oath, I should teach you to think that there are no gods, and in reality, while making my defense, should accuse myself of not believing in the gods. This, however, is far from being the case; for I believe, O Athenians! as none of my accusers do, and I leave it to you and to the deity to judge concerning me in such way as will be best both for me and for you.144
The Penalty Phase
“A Close Vote”
25. That I should not be grieved, O Athenians! at what has happened (namely, that you have condemned me) as well many other circumstances concur in bringing to pass; and, moreover this, that what has happened has not happened contrary to my expectation; but I much rather wonder at the number of votes on either side. For I did not expect that I should be condemned by so small a number, but by a large majority; but now, as it seems, if only thirty more votes had changed sides, I should have been acquitted. So far as Meletus is concerned, as it appears to me, I have been already acquitted; and not only have I been acquitted, but it is clear to everyone that had not Anytus and Lycon come forward to accuse me, he would have been fined a thousand drachmas, for not having obtained a fifth part of the votes.
“What Do I Deserve?”
26. The man, then, awards me the penalty of death. Well. But what shall I, on my part, O Athenians! award myself? Is it not clear that it will be such as I deserve? What, then, is that? Do I deserve to suffer, or to pay a fine? for that I have purposely during my life not remained quiet, but neglecting what most men seek after, money-making, domestic concerns, military command, popular oratory, and, moreover, all the magistracies, conspiracies, and cabals that are met with in the city, thinking that I was in reality too upright a man to be safe if I took part in such things, I therefore did not apply myself to those pursuits, by attending to which I should have been of no service either to you or to myself; but in order to confer the greatest benefit on each of you privately, as I affirm, I thereupon applied myself to that object, endeavoring to persuade every one of you not to take any care of his own affairs before he had taken care of himself in what way he may become the best and wisest, nor of the affairs of the city before he took care of the city itself; and that he should attend to other things in the same manner. What treatment, then, do I deserve, seeing I am such a man? Some reward, O Athenians! if, at least, I am to be estimated according to my real deserts; and, moreover, such a reward as would be suitable to me. What, then, is suitable to a poor man, a benefactor, and who has need of leisure in order to give you good advice? There is nothing so suitable, O Athenians! as that such a man should be maintained in the Prytaneum,145 and this much more than if one of you had been victorious at the Olympic games in a horserace, or in the two or four horsed chariot race: for such a one makes you appear to be happy, but I, to be so; and he does not need support, but I do. If, therefore, I must award a sentence according to my just deserts, I award this, maintenance in the Prytaneum.
27. Perhaps, however, in speaking to you thus, I appear to you to speak in the same presumptuous manner as I did respecting commiseration and entreaties; but such is not the case, O Athenians! it is rather this: I am persuaded that I never designedly injured any man, though I cannot persuade you of this, for we have conversed with each other but for a short time. For if there were the same law with you as with other men,146 that in capital cases the trial should list not only one day, but many, I think you would be persuaded; but it is not easy in a short time to do away with, great calumnies. Being persuaded, then, that I have injured no one, I am far from intending to injure myself, and of pronouncing against myself that I am deserving of punishment, and from awarding myself anything of the kind. Through fear of what? Lest I should suffer that which Meletus awards me,147 of which I say I know not whether it be good or evil? Instead of this, shall I choose what I well know to be evil, and award that? Shall I choose imprisonment? And why should I live in prison, a slave to the established magistracy, the Eleven?148 Shall I choose a fine, and to be imprisoned until I have paid it? But this is the same as that which I just now mentioned, for I have not money to pay it. Shall I, then, award myself exile? For perhaps you would consent to this award. I should indeed be very fond of life, O Athenians! if I were so devoid of reason as not to be able to reflect that you, who are my fellow-citizens, have been unable to endure my manner of life and discourses, but they have become so burdensome and odious to you that you now seek to be rid of them: others, however, will easily bear them. Far from it, O Athenians! A fine life it would be for me at my age to go out wandering, and driven from city to city, and so to live. For I well know that, wherever I may go, the youth will listen to me when I speak, as they do here. And if I repulse them, they will themselves drive me out, persuading the elders; and if I do not repulse them, their fathers and kindred will banish me on their account.
28. Perhaps, however, someone will say, “Can you not, Socrates, when you have gone from us, live a silent and quiet life?” This is the most difficult thing of all to persuade some of you. For if I say that that would be to disobey the deity, and that, therefore, it is impossible for me to live quietly, you would not believe me, thinking I spoke ironically. If, on the other hand, I say that this is the greatest good to man, to discourse daily on virtue, and other things which you have heard me discussing, examining both myself and others, but that a life without investigation is not worth living for, still less would you believe me if I said this. Such, however, is the case, as I affirm, O Athenians! though it is not easy to persuade you. And at the same time I am not accustomed to think myself deserving of any ill. If, indeed, I were rich, I would amerce149 myself in such a sum as I should be able to pay; for then I should have suffered no harm, but now—for I cannot, unless you are willing to amerce me in such a sum as I am able to pay. But perhaps I could pay you a mina of silver: in that sum, then, I amerce myself. But Plato150 here, O Athenians! and Crito Critobulus, and Apollodorus bid me amerce myself in thirty minæ, and they offer to be sureties. I amerce myself, then, to you in that sum; and they will be sufficient sureties for the money.151
Farewell to Athens
“You Have Condemned Yourselves”
29. For the sake of no long space of time, O Athenians! you will incur the character and reproach at the hands of those who wish to defame the city, of having put that wise man, Socrates, to death. For those who wish to defame you will assert that I am wise, though I am not. If, then, you had waited for a short time, this would have happened of its own accord; for observe my age, that it is far advanced in life, and near death.  And I say this, too, to the same persons. Perhaps you think, O Athenians! that I have been convicted through the want of arguments, by which I might have persuaded you, had I thought it right to do and say anything, so that I might escape punishment. Far otherwise: I have been convicted through want indeed, yet not of arguments, but of audacity and impudence, and of the inclination to say such things to you as would have been most agreeable for you to hear, had I lamented and bewailed and done and said many other things unworthy of me, as I affirm, but such as you are accustomed to hear from others. But neither did I then think that I ought, for the sake of avoiding danger, to do anything unworthy of a freeman, nor do I now repent of having so defended myself; but I should much rather choose to die, having so defended myself, than to live in that way. For neither in a trial nor in battle is it right that I or any one else should employ every possible means whereby he may avoid death; for in battle it is frequently evident that a man might escape death by laying down his arms, and throwing himself on the mercy of his pursuers. And there are many other devices in every danger, by which to avoid death, if a man dares to do and say everything. But this is not difficult, O Athenians! to escape death; but it is much more difficult to avoid depravity, for it runs swifter than death. And now I, being slow and aged, am overtaken by the slower of the two; but my accusers, being strong and active, have been overtaken by the swifter, wickedness. And now I depart, condemned by you to death; but they condemned by truth, as guilty of iniquity and injustice: and I abide my sentence, and so do they. These things, perhaps, ought so to be, and I think that they are for the best.
30. In the next place, I desire to predict to you who have condemned me, what will be your fate; for I am now in that condition in which men most frequently prophesy, namely, when they are about to die.  For you have done this, thinking you should be freed from the necessity of giving an account of your lives. The very contrary, however, as I affirm, will happen to you. Your accusers will be more numerous, whom I have now restrained, though you did not perceive it; and they will be more severe, inasmuch as they are younger, and you will be more indignant. For if you think that by putting men to death you will restrain any one from upbraiding you because you do not live well, you are much mistaken; for this method of escape is neither possible nor honorable; but that other is most honorable and most easy, not to put a check upon others, but for a man to take heed to himself how he may be most perfect. Having predicted thus much to those of you who have condemned me, I take my leave of you.
“Death is a Blessing”
31. But with you who have voted for my acquittal I would gladly hold converse on what has now taken place, while the magistrates are busy, and I am not yet carried to the place where I must die. Stay with me, then, so long, O Athenians! for nothing hinders our conversing with each other, while we are permitted to do so; for I wish to make known to you, as being my friends, the meaning of that which has just now befallen me. To me, then, O my judges! (and in calling you judges I call you rightly), a strange thing has happened. For the wonted prophetic voice of my guardian deity on every former occasion, even in the most trifling affairs, opposed me if I was about to do anything wrong; but now that has befallen me which ye yourselves behold, and which any one would think, and which is supposed to be the extremity of evil; yet neither when I departed from home in the morning did the warning of the god oppose me, nor when I came up here to the place of trial, nor in my address when I was about to say anything; yet on other occasions it has frequently restrained me in the midst of speaking. But now it has never, throughout this proceeding, opposed me, either in what I did or said. What, then, do I suppose to be the cause of this? I will tell you: what has befallen me appears to be a blessing; and it is impossible that we think rightly who suppose that death is an evil. A great proof of this to me is the fact that it is impossible but that the accustomed signal should have opposed me, unless I had been about to meet with some good.
32. Moreover, we may hence conclude that there is great hope that death is a blessing. For to die is one of two things: for either the dead may be annihilated, and have no sensation of anything whatever; or, as it is said, there are a certain change and passage of the soul from one place to another. And if it is a privation of all sensation, as it were a sleep in which the sleeper has no dream, death would be a wonderful gain. For I think that if any one, having selected a night in which he slept so soundly as not to have had a dream, and having compared this night with all the other nights and days of his life, should be required, on consideration, to say how many days and nights he had passed better and more pleasantly than this night throughout his life, I think that not only a private person, but even the great king himself, would find them easy to number, in comparison with other days and nights. If, therefore, death is a thing of this kind, I say it is a gain; for thus all futurity appears to be nothing more than one night. But if, on the other hand, death is a removal from hence to another place, and what is said be true, that all the dead are there, what greater blessing can there be than this, my judges? For if, on arriving at Hades,152 released from these who pretend to be judges, one shall find those who are true judges, and who are said to judge there, Minos and Rhadamanthus,153 Æacus154 and Triptolemus,155 and such others of the demi-gods as were just during their own life, would this be a sad removal? At what price would you not estimate a conference with Orpheus156 and Musæus,157 Hesiod158 and Homer?159 I indeed should be willing to die often, if this be true. For to me the sojourn there would be admirable, when I should meet with Palamedes, and Ajax, son of Telamon,160 and any other of the ancients who has died by an unjust sentence. The comparing my sufferings with theirs would, I think, be no unpleasing occupation. But the greatest pleasure would be to spend my time in questioning and examining the people there as I have done those here, and discovering who among them is wise, and who fancies himself to be so, but is not. At what price, my judges, would not any one estimate the opportunity of questioning him who led that mighty army against Troy, or Ulysses,161 or Sisyphus, or ten thousand others whom one might mention both men and women, with whom to converse and associate, and to question them, would be an inconceivable happiness? Surely for that the judges there do not condemn to death; for in other respects those who live there are more happy than those who are here, and are henceforth immortal, if, at least, what is said be true.
33. You, therefore, O my judges! ought to entertain good hopes with respect to death, and to meditate on this one truth, that to a good man nothing is evil, neither while living nor when dead, nor are his concerns neglected by the gods. And what has befallen me is not the effect of chance; but this is clear to me, that now to die, and be freed from my cares is better for me. On this account the warning162 in no way turned me aside; and I bear no resentment toward those who condemned me, or against my accusers, although they did not condemn and accuse me with this intention, but thinking to injure me: in this they deserve to be blamed.
“Goodbye”
Thus much, however, I beg of them. Punish my sons when they grow up, O judges! paining them as I have pained you, if they appear to you to care for riches or anything else before virtue; and if they think themselves to be something when they are nothing, reproach them as I have done you, for not attending to what they ought, and for conceiving themselves to be something when they are worth nothing. If ye do this, both I and my sons shall have met with just treatment at your hands.
But it is now time to depart—for me to die, for you to live. But which of us is going to a better state is unknown to everyone but God.


8 Data Analysis 2
8.2 Measures of Dispersion
Learning Objectives
By the end of this section the student should be able to:
- Determine the range for a data set.
- Determine the standard deviation for a data set.
- Determine the standard deviation from a histogram
Measures of Dispersion or Spread
We have seen that measures of central tendency, including the mean and median, are used to identify a central position within a data set. They indicate where the data clusters.
Consider student A’s scores on five tests: 32% 95% 89% 74% 55% The mean, or average, is (32 + 95 + 89 + 74 + 55)/5 = 69% and the median is 74%.
Consider student B’s scores on the same five tests: 68% 69% 72% 74% 62% The mean, or average, is (68 + 69 + 72 + 74 + 62)/5 = 69% and the median is 69%.
Both student’s have the same test average of 69% but there is a substantial difference in the spread or dispersion of their scores. Student A’s test scores range from a low score of 32% to a high score of 95% so the spread in marks is 63 percentage points. Student B’s test scores range from a low score of 62% to a high score of 74% so the spread in marks is 12 percentage points.
When we analyze data it is important to consider how dispersed or spread out the data values are. In this section we will consider two measures of dispersion.
Range
Range is one measure of dispersion. A measure of dispersion is used to describe the spread of data.
Range
The range indicates the total spread in data values. It is the difference between the highest and lowest data values.
Range = highest data value – lowest data value
EXAMPLE 1
The table shows the daily high temperature (°C) over a three week period.
Determine the highest temperature, lowest temperature, and the range in daily high temperatures over the three weeks.
Solution
The highest temperature was 29º, the lowest temperature was 16°, and the range in temperatures was 29 – 16 = 13º.
TRY IT 1
The table shows the test score for a group of fourteen students.
Determine the highest test score, the lowest test score, and the range in test scores for the group of 14 students.
Show answer
The highest score was 89%, the lowest score was 56%, and the range in scores was 33%.
An advantage of using the range as a measure of dispersion is that it involves a simple calculation. A disadvantage is that the range only provides a measure between the highest and lowest values so it disregards all other data values. If the highest or lowest data value is an outlier then the range will not provide a true measure of the spread in the typical values.
EXAMPLE 2
A student wrote five tests and earned the following five scores:
92% 95% 89% 94% 35%
- Determine the mean, median and the range for these five scores.
- Which of the five scores is an outlier?
- Remove the outlier and recalculate the mean, median and the range for the four remaining scores.
- Comparing the results for the five scores versus four scores, which of the three measures was least impacted by the outlier?
- Comparing the results for the five scores versus four scores, which of the three measures was most impacted by the outlier?
Solution
1. The student’s mean score: (92 + 95 + 89 + 94 + 35) / 5 = 81%
The median score is 92%.
The range in marks is 95% – 35% = 60%.
2. The score of 35% is an outlier.
3. The student’s mean score: (92 + 95 + 89 + 94) / 4 = 92.5%
The median score is 93%.
The range in marks is 95% – 89% = 6%.
4. The median was least impacted by the removal of the outlier.
5. The range was most impacted by the outlier.
TRY IT 2
The following seven values are salaries at a local computer company.
$62,000 $95, 000 $120,000 $101, 000 $99,000 $98,000 $110,000
- Determine the mean, median and the range for these seven salaries.
- Which of the seven salaries is an outlier?
- Remove the outlier and recalculate the mean, median and the range for the six remaining salaries.
- Comparing the results for the seven versus six salaries, which of the three measures was least impacted by the outlier?
- Comparing the results for the seven versus six salaries, which of the three measures was most impacted by the outlier?
Show answer
- mean salary $97,857; median salary $99,000; range in salaries $58,000
- $62,000
- mean salary $103, 833; median salary $100,000; range in salaries $25,000
- the median
- the range
Refer back to Example 2 and the measures that were calculated for five test scores.The student’s mean score is 81% and the range in marks is 60%. The range of 60% does not capture the fact that if the outlier is removed then there is a spread of only 6% for the four remaining data values. The range depends on only the highest and lowest data values. The existence of an outlier can result in a misleading representation of the spread in data values.
An alternative measure of dispersion is called the standard deviation. It depends on all data values rather than on only the highest and lowest data values.
Standard Deviation
Standard deviation measures the dispersion of the data values around the mean. Unlike the range, its value depends on every data value in the data set. The standard deviation is found by determining how much each data value differs from the mean.
What does the standard deviation actually tell us? Consider two sets of test scores:
Set A: 76% 74% 86% 84% 85%
Set B: 53% 95% 62% 99% 96%
Refer to Figure 1. For both sets the mean is 81%. If we plot the scores (indicated by the *) on a scale of 0% to 100% we see that the scores in Set A are much less spread out around the mean. The scores from Set B are much more dispersed.
If we compare the standard deviations for the two data sets we should find that although the mean is the same, the standard deviation for Set B will be greater since the data is more widely spread out from the mean.
Population versus Sample Standard Deviation
When working with standard deviation it is important to distinguish whether you are working with the entire population or a sample of the population. Statisticians generally survey a sample of the population because it is often impossible to survey the entire population. As an example, assume your university wants to determine food preferences for its entire student body. The population would be all students enrolled in the university. Rather than attempt to survey every student, the university will survey only a sample.
The symbolic representation of standard deviation is different for a population versus a sample. If you are working with an entire population, the symbol for standard deviation is the Greek letter sigma, σ. The symbol for the standard deviation of a sample is s. Similarly, the calculation of standard deviation is different for a population versus a sample. Unless otherwise indicated in this chapter, we will assume that we are working with a sample, rather than an entire population.
Standard Deviation Formula
Standard Deviation Formula for a Population
The Greek letter sigma ∑ is the summation symbol. It indicates that all of the values (x – μ)2 must be added.
Standard Deviation Formula for a Sample
Calculating the Standard Deviation
When calculating the standard deviation with the aid of a scientific calculator it is helpful to record the steps using a table.
Calculating Standard Deviation
We will use the formula for finding the standard deviation of a sample:
To determine the standard deviation for a sample we will use the following steps :
- Find the mean
- Create a table with three columns: data value, data value – mean, (data value – mean)2
- Fill in the data value column with all values from the sample
- Subtract the mean from each data value: (data value – mean)
- Square the results from step 4: (data value – mean)2
- Sum the results in column 3 (from step 5)
- Divide the sum (from step 6) by (n – 1)
- Find the square root of the result in step 7
EXAMPLE 3
a) Determine the standard deviation for the sample set A test scores: 76% 74% 86% 84% 85%
b) Determine the standard deviation for the sample set B test scores: 53% 95% 62% 99% 96%
c) Compare the means and standard deviations for Set A and Set B. Which set is more spread out (dispersed)?
Solution
a)
The standard deviation for Set A is 5.57 (rounded to 2 decimal places)
b)
The standard deviation for Set B is 21.74 (rounded to 2 decimal places).
c)
In comparing the two data sets A and B:
- The means are the same value of 81.
- The standard deviation for Set A is s = 5.57 and for Set B it is s = 21.74. The much larger standard deviation for Set B indicates that there is a much greater spread in the data values around the mean of 81%.
Note that the sum of the middle column (data value – mean) is 0. This will always be the case. That is why we must square the values before we add them, as is done in column 3.
TRY IT 3
The average high temperatures (in ºC) for one week in April for two different cities in Canada were as follows:
City A: 15 19 22 26 21 19 18
City B: 6 9 15 18 20 19 21
a) Calculate the mean high temperature (if necessary round to 2 decimal places) for each city. Which of the two cities appears to have a wider spread in temperatures around their means?
b) Calculate the standard deviation for each temperature set (if necessary round to 2 decimal places) to see if your observation is correct.
Show answer
The mean for City A is 20 ˚C and the mean for City B was 15.43˚C.
The standard deviation for City A is 3.46 and for City B is 5.80. City B’s temperatures are more widely spread out from the mean temperature.
We have seen that two measures of spread or dispersion are the range and the standard deviation. Although the range is a much simpler calculation, it only takes into consideration the highest and lowest data values. The existence of an outlier can result in a range that is not truly indicative of the spread in data values. The standard deviation is a more complex calculation but takes into consideration all data values. It is important to note that technology is often used to calculate the standard deviation which eliminates the need for tedious calculations.
EXAMPLE 4
In Example 1 the range for the following set of temperature was determined to be 13 ºC.
a) Determine the mean and the standard deviation.
b) Explain why the values for the range and standard deviation are different.
Solution
a) The mean (average) is 22.29 ˚C and the standard deviation is 3.86.
b) The reason for the difference in values is that the range only tells us the difference between the highest and lowest temperature whereas the standard deviation tells us how widespread the temperatures are in relation to the mean temperature of 22.29 ˚C
TRY IT 4
Refer back to TRY IT 1 and the test scores for a group of 14 students. The range was determined to be 33.
Determine the mean (rounded to the nearest whole number) and the standard deviation (rounded to the nearest 2 decimal places) for this set of test scores.
Show answer
The mean is 72 and the standard deviation is 8.19.
Histograms and the Dispersion of Data Values
We have seen that for two data sets with the same mean, when the standard deviation is larger the data values are more spread out. A histogram can be used to illustrate the spread of data values.
Consider a dance competition where teams comprised of seven dancers compete for the prize money in several different dance categories. There were four teams entered in the elite category. The dancers must be between the ages of 18-24 years old. The age breakdown for the members of the four teams in the elite category is:
Team Unity: all seven dancers are age 21
Team Harmony: 2 dancers are 20, 3 dancers are 21 and 2 dancers are 22
Team Mix: 1 dancer is 19, 2 dancers are 20, 1 dancer is 21, 2 dancers are 22 and 1 dancer is 23
Team Extend: 3 dancers are 18, 1 dancer is 21, and 3 dancers are 24
The mean age for all four teams is 21 but the standard deviations for each of the four teams are different. Team Unity has a standard deviation of 0, Team Harmony has a standard deviation of 0.82, Team Mix has a standard deviation of 1.412 and Team Extend has a standard deviation of 3.
The histograms for each of the teams appears in Figures 2a through Figures 2d below.
In Figure 2a Team Unity has a standard deviation of 0 since all ages are the same. None of the ages spread out from the mean of 21.
In Figure 2b Team Harmony has a standard deviation of 0.82 years. The histogram illustrates that the ages are closely clustered around the mean of 21.
In Figure 2c Team Mix has a standard deviation of 1.41. The histogram illustrates that the data (age) spread is greater than for Team Unity and Team Harmony.
In Figure 2d Team Extend has a standard deviation of 3. The histogram clearly illustrates that the ages for this team are the most spread out from the mean of 21.
EXAMPLE 5
Ten participants in a group fitness class were asked to rank the class on a scale from 1 to 5. Determine the mean and standard deviation for the evaluation scores as depicted in the histogram below.
Solution
TRY IT 5
The hourly wages for ten employees at a small coffee shop are illustrated in the histogram. Determine the mean and standard deviation for the employee hourly wages.
Show answer
The mean is $17.80 and the standard deviation is $1.32
We have seen that standard deviation provides us with a measure of the spread of data values in relation to the mean. We have learned how to calculate the standard deviation for a data set but we have not explored the significance or meaning of these calculated values. In the next section we will explore the significance of the calculated values as we consider the relationship between the standard deviation and the distribution of the data values.
Key Concepts
- Two measures of dispersion or spread in data values are:
- Range = highest data value – lowest data value
- Standard deviation. Unlike the range, its value depends on every data value in the data set. It is found by determining how much each data value differs from the mean.
Glossary
histogram
represents the frequency distribution (number of occurrences) of each data value. The data values are grouped into intervals or “bins”.
outlier
A data observation that is deemed to be unusual based on the pattern of the other data values.
range
indicates the total spread in data values. It is the difference between the highest and lowest data values.
sigma
is the uppercase Greek letter written ∑. It is used to indicate the sum of a series of values.
standard deviation
measures the dispersion of the data values around the mean.
8.2 Exercise Set
- The daily high temperature (in degrees C) for Calgary AB was recorded over a period of two weeks:
28 25 26 27 27 29 30 30 12 20 22 25 24 25 - Determine the mean, median and the range for these fourteen temperatures.
- Which of the temperatures appears to be an outlier?
- Remove the outlier and recalculate the mean, median and the range for the thirteen remaining values.
- Comparing the results for the fourteen temperature values versus thirteen temperature values, which of the three measures was most impacted by the outlier?
- The population of Cache Creek, B.C. for the years 2011 to 2019 is provided in the table below (Demographic Analysis Section, BC Stats)
- Determine the mean and median population.
- Determine the range.
- Determine the standard deviation.
- Set A: 6 7 7 10 10 11Set B: 10 11 12 13 14 15Set C: 10 12 16 11 12 13
- For each of the three data samples below, calculate the range, mean, and standard deviation.
- Based on these calculations, determine any similarities that exist between any of the data samples.
- Which of the three measures is different for every set?
- Given the two data samples Set A and Set B below, which appears to have the greatest spread in values?
- Set A: 69 86 74 60 67 65
- Set B: 50 51 86 50 52 51
- For each sample calculate the mean, range and standard deviation. If necessary round final answers to 2 decimal places.
- Based on these calculations which sample has the larger standard deviation?
- If the 86 in each data set is changed to a 56 which set would you predict would have the greatest change in standard deviation? Recalculate the standard deviations with a value of 56 instead of 86. Is your prediction correct?
- Set A: 69 56 74 60 67 65
- Set B: 50 51 56 50 52 51
- The standard deviation for a sample is calculated to be 0. What can you conclude about the data values?
- The maximum hourly wage (in dollars/hour) for pipefitters and carpenters in the ten Canadian provinces is listed below.(Source: Wages for Steamfitters, pipefitters and sprinkler system installers from the Canadian Job Bank)
- Pipefitter: 48 47 45 45 40 48 42 50 46 43
- Carpenter: 36 33 25 28 39 36 33 35 39 35
- Without calculating the average, which occupation appears to have the higher average maximum hourly wage?
- Calculate the average (mean) maximum hourly wage (to the nearest cent) for each occupation.
- Determine the range in maximum hourly wages for each occupation. Which occupation has a greater range in hourly wages?
- Calculate the standard deviation (to the nearest cent) for each occupation. Which occupation has a maximum hourly wage that is more spread out?
- Revisit question #1. The daily high temperature (in degrees C) for Calgary AB was recorded over a period of two weeks:
28 25 26 27 27 29 30 30 12 20 22 25 24 25 - Calculate the standard deviation for the fourteen temperature values.
- Remove the outlier and recalculate the standard deviation for the thirteen temperature values. How has the standard deviation changed with the removal of the outlier?
- Two histograms are provided below:
- For each histogram determine the range, mean, and standard deviation.
- Considering only the means and ranges, what can you conclude about the spread or dispersion of the data values for each set?
- Considering only the means and standard deviations, what can you conclude about the spread or dispersion of the data values for each set?
Answers
-
- mean 25; median 25.5, range 18
- outlier is 12
- mean 26; median 26, range 10
- The range was most impacted by the removal of the outlier.
- mean is 1022; median is 1021
- 58
- standard deviation = 21.40
- Set A: range is 5; mean is 8.5; standard deviation is 2.07Set B: range is 5; mean is 12.5; standard deviation is 1.87Set C: range is 6; mean is 12.33; standard deviation is 2.07
- Set A and Set B have identical ranges but different means and standard deviations.Set A and Set C have the same standard deviation but different ranges.
- Each set has a different mean.
- Answers may vary. Set A scores appear to be more spread out; aside from one score of 86, the scores in Set B are less spread out.
- Set A: range is 26; mean is 70.17; standard deviation is 9.02Set B: range is 36; mean is 56.67; standard deviation is 14.39
- Set B has a larger standard deviation.
- Predictions will vary. For Set A the new standard deviation is 6.43 (compared to 9.02); Set B has a new standard deviation of 2.25 (compared to 14.39) so set B had the greatest change in standard deviation.
- All data values are equal.
- pipefitter
- pipefitter ‘s top hourly wage on average is $45.40/hour; carpenter’s top hourly wage on average is $33.90/hour
- pipefitter range of $10/hour for the 10 provincescarpenter range of $14/hour for the 10 provincesThe carpenter has a greater range in wages
- pipefitter has a standard deviation of $3.06 and the carpenter has a standard deviation of $4.46. The carpenter has a higher standard deviation and therefore the carpenter’s hourly wage is more spread out.
- Standard deviation is 4.71
- Standard deviation is 2.97; With the removal of the outlier this value has become smaller
- Histogram A: range is 40, mean is 75, standard deviation is 11.88Histogram B: range is 40, mean is 75, standard deviation is 15.34
- Considering only the means and ranges, these are both identical so it would appear that the data values are equally dispersed.
- Histogram B has a greater dispersion of data as indicated by the larger standard deviation.


76 Mercury
Learning Objectives
By the end of this section, you will be able to:
- Characterize the orbit of Mercury around the Sun
- Describe Mercury’s structure and composition
- Explain the relationship between Mercury’s orbit and rotation
- Describe the topography and features of Mercury’s surface
- Summarize our ideas about the origin and evolution of Mercury
The planet Mercury is similar to the Moon in many ways. Like the Moon, it has no atmosphere, and its surface is heavily cratered. As described later in this chapter, it also shares with the Moon the likelihood of a violent birth.
Mercury’s Orbit
Mercury is the nearest planet to the Sun, and, in accordance with Kepler’s third law, it has the shortest period of revolution about the Sun (88 of our days) and the highest average orbital speed (48 kilometers per second). It is appropriately named for the fleet-footed messenger god of the Romans. Because Mercury remains close to the Sun, it can be difficult to pick out in the sky. As you might expect, it’s best seen when its eccentric orbit takes it as far from the Sun as possible.
The semimajor axis of Mercury’s orbit—that is, the planet’s average distance from the Sun—is 58 million kilometers, or 0.39 AU. However, because its orbit has the high eccentricity of 0.206, Mercury’s actual distance from the Sun varies from 46 million kilometers at perihelion to 70 million kilometers at aphelion (the ideas and terms that describe orbits were introduced in Orbits and Gravity).
Composition and Structure
Mercury’s mass is one-eighth that of Earth, making it the smallest terrestrial planet. Mercury is the smallest planet (except for the dwarf planets), having a diameter of 4878 kilometers, less than half that of Earth. Mercury’s density is 5.4 g/cm3, much greater than the density of the Moon, indicating that the composition of those two objects differs substantially.
Mercury’s composition is one of the most interesting things about it and makes it unique among the planets. Mercury’s high density tells us that it must be composed largely of heavier materials such as metals. The most likely models for Mercury’s interior suggest a metallic iron-nickel core amounting to 60% of the total mass, with the rest of the planet made up primarily of silicates. The core has a diameter of 3500 kilometers and extends out to within 700 kilometers of the surface. We could think of Mercury as a metal ball the size of the Moon surrounded by a rocky crust 700 kilometers thick (Figure 1). Unlike the Moon, Mercury does have a weak magnetic field. The existence of this field is consistent with the presence of a large metal core, and it suggests that at least part of the core must be liquid in order to generate the observed magnetic field.
Example 1: Densities of Worlds
The average density of a body equals its mass divided by its volume. For a sphere, density is:
Astronomers can measure both mass and radius accurately when a spacecraft flies by a body.
Using the information in this chapter, we can calculate the approximate average density of the Moon.
[reveal-answer q=”593698″]Show Answer[/reveal-answer]
[hidden-answer a=”593698″]For a sphere,
gives a value of 3.3 g/cm3, which is 3.3 × 103 kg/m3.[/hidden-answer]
Check Your Learning
Using the information in this chapter, calculate the average density of Mercury. Show your work. Does your calculation agree with the figure we give in this chapter?
[reveal-answer q=”80470″]Show Answer[/reveal-answer]
[hidden-answer a=”80470″]
That matches the value given when g/cm3 is converted into kg/m3.[/hidden-answer]
Mercury’s Strange Rotation
Visual studies of Mercury’s indistinct surface markings were once thought to indicate that the planet kept one face to the Sun (as the Moon does to Earth). Thus, for many years, it was widely believed that Mercury’s rotation period was equal to its revolution period of 88 days, making one side perpetually hot while the other was always cold.
Radar observations of Mercury in the mid-1960s, however, showed conclusively that Mercury does not keep one side fixed toward the Sun. If a planet is turning, one side seems to be approaching Earth while the other is moving away from it. The resulting Doppler shift spreads or broadens the precise transmitted radar-wave frequency into a range of frequencies in the reflected signal (Figure 2). The degree of broadening provides an exact measurement of the rotation rate of the planet.
Mercury’s period of rotation (how long it takes to turn with respect to the distant stars) is 59 days, which is just two-thirds of the planet’s period of revolution. Subsequently, astronomers found that a situation where the spin and the orbit of a planet (its year) are in a 2:3 ratio turns out to be stable. (See What Difference a Day Makes for more on the effects of having such a long day on Mercury.)
Mercury, being close to the Sun, is very hot on its daylight side; but because it has no appreciable atmosphere, it gets surprisingly cold during the long nights. The temperature on the surface climbs to 700 K (430 °C) at noontime. After sunset, however, the temperature drops, reaching 100 K (–170 °C) just before dawn. (It is even colder in craters near the poles that receive no sunlight at all.) The range in temperature on Mercury is thus 600 K (or 600 °C), a greater difference than on any other planet.
What a Difference a Day Makes
Mercury rotates three times for each two orbits around the Sun. It is the only planet that exhibits this relationship between its spin and its orbit, and there are some interesting consequences for any observers who might someday be stationed on the surface of Mercury.
Here on Earth, we take for granted that days are much shorter than years. Therefore, the two astronomical ways of defining the local “day”—how long the planet takes to rotate and how long the Sun takes to return to the same position in the sky—are the same on Earth for most practical purposes. But this is not the case on Mercury. While Mercury rotates (spins once) in 59 Earth days, the time for the Sun to return to the same place in Mercury’s sky turns out to be two Mercury years, or 176 Earth days. (Note that this result is not intuitively obvious, so don’t be upset if you didn’t come up with it.) Thus, if one day at noon a Mercury explorer suggests to her companion that they should meet at noon the next day, this could mean a very long time apart!
To make things even more interesting, recall that Mercury has an eccentric orbit, meaning that its distance from the Sun varies significantly during each mercurian year. By Kepler’s law, the planet moves fastest in its orbit when closest to the Sun. Let’s examine how this affects the way we would see the Sun in the sky during one 176-Earth-day cycle. We’ll look at the situation as if we were standing on the surface of Mercury in the center of a giant basin that astronomers call Caloris (Figure 4).
At the location of Caloris, Mercury is most distant from the Sun at sunrise; this means the rising Sun looks smaller in the sky (although still more than twice the size it appears from Earth). As the Sun rises higher and higher, it looks bigger and bigger; Mercury is now getting closer to the Sun in its eccentric orbit. At the same time, the apparent motion of the Sun slows down as Mercury’s faster motion in orbit begins to catch up with its rotation.
At noon, the Sun is now three times larger than it looks from Earth and hangs almost motionless in the sky. As the afternoon wears on, the Sun appears smaller and smaller, and moves faster and faster in the sky. At sunset, a full Mercury year (or 88 Earth days after sunrise), the Sun is back to its smallest apparent size as it dips out of sight. Then it takes another Mercury year before the Sun rises again. (By the way, sunrises and sunsets are much more sudden on Mercury, since there is no atmosphere to bend or scatter the rays of sunlight.)
Astronomers call locations like the Caloris Basin the “hot longitudes” on Mercury because the Sun is closest to the planet at noon, just when it is lingering overhead for many Earth days. This makes these areas the hottest places on Mercury.
We bring all this up not because the exact details of this scenario are so important but to illustrate how many of the things we take for granted on Earth are not the same on other worlds. As we’ve mentioned before, one of the best things about taking an astronomy class should be ridding you forever of any “Earth chauvinism” you might have. The way things are on our planet is just one of the many ways nature can arrange reality.
The Surface of Mercury
The first close-up look at Mercury came in 1974, when the US spacecraft Mariner 10 passed 9500 kilometers from the surface of the planet and transmitted more than 2000 photographs to Earth, revealing details with a resolution down to 150 meters.
Subsequently, the planet was mapped in great detail by the MESSENGER spacecraft, which was launched in 2004 and made multiple flybys of Earth, Venus, and Mercury before settling into orbit around Mercury in 2011. It ended its life in 2015, when it was commanded to crash into the surface of the planet.
Mercury’s surface strongly resembles the Moon in appearance (Figure 3 and Figure 4). It is covered with thousands of craters and larger basins up to 1300 kilometers in diameter. Some of the brighter craters are rayed, like Tycho and Copernicus on the Moon, and many have central peaks. There are also scarps (cliffs) more than a kilometer high and hundreds of kilometers long, as well as ridges and plains.
MESSENGER instruments measured the surface composition and mapped past volcanic activity. One of its most important discoveries was the verification of water ice (first detected by radar) in craters near the poles, similar to the situation on the Moon, and the unexpected discovery of organic (carbon-rich) compounds mixed with the water ice.
Most of the mercurian features have been named in honor of artists, writers, composers, and other contributors to the arts and humanities, in contrast with the scientists commemorated on the Moon. Among the named craters are Bach, Shakespeare, Tolstoy, Van Gogh, and Scott Joplin.
There is no evidence of plate tectonics on Mercury. However, the planet’s distinctive long scarps can sometimes be seen cutting across craters; this means the scarps must have formed later than the craters (Figure 5). These long, curved cliffs appear to have their origin in the slight compression of Mercury’s crust. Apparently, at some point in its history, the planet shrank, wrinkling the crust, and it must have done so after most of the craters on its surface had already formed.
If the standard cratering chronology applies to Mercury, this shrinkage must have taken place during the last 4 billion years and not during the solar system’s early period of heavy bombardment.
The Origin of Mercury
The problem with understanding how Mercury formed is the reverse of the problem posed by the composition of the Moon. We have seen that, unlike the Moon, Mercury is composed mostly of metal. However, astronomers think that Mercury should have formed with roughly the same ratio of metal to silicate as that found on Earth or Venus. How did it lose so much of its rocky material?
The most probable explanation for Mercury’s silicate loss may be similar to the explanation for the Moon’s lack of a metal core. Mercury is likely to have experienced several giant impacts very early in its youth, and one or more of these may have torn away a fraction of its mantle and crust, leaving a body dominated by its iron core.
Today, astronomers recognize that the early solar system was a chaotic place, with the final stages of planet formation characterized by impacts of great violence. Some objects of planetary mass have been destroyed, whereas others could have fragmented and then re-formed, perhaps more than once. Both the Moon and Mercury, with their strange compositions, bear testimony to the catastrophes that must have characterized the solar system during its youth.
Key Concepts and Summary
Mercury is the nearest planet to the Sun and the fastest moving. Mercury is similar to the Moon in having a heavily cratered surface and no atmosphere, but it differs in having a very large metal core. Early in its evolution, it apparently lost part of its silicate mantle, probably due to one or more giant impacts. Long scarps on its surface testify to a global compression of Mercury’s crust during the past 4 billion years.


Chapter 16 (Administration of Medications via Other Routes)
Open Resources for Nursing (Open RN)
Answer Key to Chapter 16 Learning Activities
- Patients suffering from nausea or experiencing difficulty swallowing may not tolerate medications administered via the enteral route. For a patient experiencing pain, appropriate alternate methods of medication administration may be transdermal medication administration. Transdermal medications are beneficial in that they provide a consistent level of drug into the bloodstream during distribution.
- B – when placing a patch, the nurse should press firmly to the skin to ensure adequate adherence, C – gloves are required for patch application and removal, E – date and location of patch application should be promptly documented in the medication administration record (MAR).
Answers to interactive elements are given within the interactive element.