File 38 of A Treatise of Human Nature by David Hume, Volume 1. This LibriVox recording is in the public domain. Recording by George Yeager, Book 1, Part 4, Section 6 of Personal Identity. There are some philosophers who imagine we are, every moment, intimately conscious of what we call our self, that we feel its existence and its continuance in existence, and are certain beyond the evidence of a demonstration both of its perfect identity and simplicity. The strongest sensation, the most violent passion, say they, instead of distracting us from this view, only fix it the more intensely, and make us consider their influence on self either by their pain or pleasure. To attempt a farther proof of this were to weaken its evidence, since no proof can be derived from any fact of which we are so intimately conscious, nor is there anything of which we can be certain if we doubt of this. Unluckily all these positive assertions are contrary to that very experience which is pleaded for them, nor have we any idea of self after the manner it is here explained. For from what impression could this idea be derived? This question it is impossible to answer without a manifest contradiction and absurdity, and yet it is a question which must necessarily be answered if we would have the idea of self pass for clear and intelligible, it must be some one impression that gives rise to every real idea. That self or person is not any one impression, but that to which our several impressions and ideas are supposed to have a reference. If any impression gives rise to the idea of self, that impression must continue invariably the same through the whole course of our lives, since self is supposed to exist after that manner. But there is no impression constant and invariable. Pain and pleasure, grief and joy, passions and sensations succeed each other and never all exist at the same time. It cannot therefore be from any of these impressions or from any other that the idea of self is derived, and consequently there is no such idea. But further, what must become of all our particular perceptions upon this hypothesis? All these are different and distinguishable and separable from each other and may be separately considered and may exist separately and have no need of anything to support their existence. After what manner therefore do they belong to self, and how are they connected with it? For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception and never can observe anything but the perception. When my perceptions are removed for any time, as by sound sleep, so long am I insensible of myself and may truly be said not to exist. And were all my perceptions removed by death, and could I neither think nor feel nor see, nor love nor hate, after the dissolution of my body, I should be entirely annihilated, nor do I conceive what is farther requisite to make me a perfect non-entity. If anyone, upon serious and unprejudiced reflection, thinks he has a different notion of himself, I must confess I can reason no longer with him. All I can allow him is that he may be in the right as well as I, and that we are essentially different in this particular. He may perhaps perceive something simple and continued, which he calls himself, though I am certain there is no such principle in me. But setting aside some metaphysicians of this kind, I may venture to affirm of the rest of mankind that they are nothing but a bundle or collection of different perceptions which succeed each other with an inconceivable rapidity and are in a perpetual flux and movement. Our eyes cannot turn in their sockets without varying our perceptions. Our thought is still more variable than our sight. And all our other senses and faculties contribute to this change, nor is there any single power of the soul which remains unalterably the same perhaps for one moment. The mind is a kind of theatre where several perceptions successively make their appearance, pass, repass, glide away, and mingle in an infinite variety of postures and situations. There is properly no simplicity in it at one time, nor identity indifferent, whatever natural propension we may have to imagine that simplicity and identity. The comparison of the theatre must not mislead us. They are the successive perceptions only that constitute the mind. Or have we the most distant notion of the place where these scenes are represented, or of the materials of which it is composed? What then gives us so great a propension to ascribe an identity to these successive perceptions, and to suppose ourselves possessed of an invariable and uninterrupted existence through the whole course of our lives? In order to answer this question, we must distinguish betwixt personal identity as it regards our thought or imagination, and as it regards our passions or the concern we take in ourselves. The first is our present subject, and to explain it perfectly, we must take the matter pretty deep and account for that identity which we attribute to plants and animals. There being a great analogy betwixt it and the identity of a self or person. We have a distinct idea of an object that remains invariable and uninterrupted through a supposed variation of time, and this idea we call that of identity or sameness. We have also a distinct idea of several different objects existing in succession and connected together by a close relation, and this to an accurate view affords as perfect a notion of diversity as if there was no manner of relation among the objects. But though these two ideas of identity and a succession of related objects be in themselves perfectly distinct and even contrary, yet it is certain that in our common way of thinking they are generally confounded with each other. That action of the imagination by which we consider the uninterrupted and invariable object and that by which we reflect on the succession of related objects are almost the same to the feeling, nor is there much more effort of thought required in the latter case than in the former. The relation facilitates the transition of the mind from one object to another and renders its passage as smooth as if it contemplated one continued object. This resemblance is the cause of the confusion and mistake, and makes us substitute the notion of identity instead of that of related objects. However, at one instant we may consider the related succession as variable or interrupted, we are sure the next to ascribe to it a perfect identity and regard it as invariable and uninterrupted. Our propensity to this mistake is so great from the resemblance above mentioned that we fall into it before we are aware, and though we incessantly correct ourselves by reflection and return to a more accurate method of thinking, yet we cannot long sustain our philosophy or take off this bias from the imagination. Our last resource is to yield to it and boldly assert that these different related objects are in effect the same, however interrupted and variable. In order to justify to ourselves this absurdity, we often feign some new and unintelligible principle that connects the objects together and prevents their interruption or variation. Thus we feign the continued existence of the perceptions of our senses to remove the interruption and run into the notion of a soul and self and substance to disguise the variation. But we may further observe that where we do not give rise to such a fiction, our propensity to confound identity with relation is so great that we are apt to imagine, see footnote 10, something unknown and mysterious connecting the parts beside their relation. And this I take to be the case with regard to the identity we ascribe to plants and vegetables. And even when this does not take place, we still feel a propensity to confound these ideas, though we are not able fully to satisfy ourselves in that particular, nor find anything invariable and uninterrupted to justify our notion of identity. Footnote 10. If the reader is desirous to see how a great genius may be influenced by the seemingly trivial principles of the imagination, as well as the mere vulgar, let him read my Lord Shaftesbury's reasonings concerning the uniting principle of the universe and the identity of plants and animals, see his moralists or philosophical rhapsody. End of footnote 10. Thus the controversy concerning identity is not merely a dispute of words, for when we attribute identity in an improper sense to variable or interrupted objects, our mistake is not confined to the expression, but is commonly attended with a fiction, either of something invariable and uninterrupted, or of something mysterious and inexplicable, or at least with a propensity to such fictions. What will suffice to prove this hypothesis to the satisfaction of every fair inquirer is to shoo from daily experience and observation that the objects which are variable or interrupted and yet are supposed to continue the same are such only as consist of a succession of parts connected together by resemblance, contiguity, or causation. Whereas such a succession answers evidently to our notion of diversity, it can only be by mistake we ascribe to it an identity. And as the relation of parts which leads us into this mistake is really nothing but a quality which produces an association of ideas and an easy transition of the imagination from one to another. It can only be from the resemblance which this act of the mind bears to that by which we contemplate one continued object that the error arises. Our chief business then must be to prove that all objects to which we ascribe identity without observing their invariableness and uninterruptedness are such as consist of a succession of related objects. In order to this suppose any mass of matter of which the parts are contiguous and connected to be placed before us. It is plain we must attribute a perfect identity to this mass, provided all the parts continue uninterruptedly and invariably the same, whatever motion or change of place we may observe either in the whole or in any of the parts. But supposing some very small or inconsiderable part to be added to the mass or subtracted from it, though this absolutely destroys the identity of the whole strictly speaking, yet as we seldom think so accurately we scruple not to pronounce a mass of matter the same where we find so trivial an alteration. The passage of the thought from the object before the change to the object after it is so smooth and easy that we scarce perceive the transition and are apt to imagine that it is nothing but a continued survey of the same object. There is a very remarkable circumstance that attends this experiment which is that though the change of any considerable part in a mass of matter destroys the identity of the whole, yet we must measure the greatness of the part not absolutely but by its proportion to the whole. The addition or diminution of a mountain would not be sufficient to produce a diversity in a planet, though the change of a very few inches would be able to destroy the identity of some bodies. It will be impossible to account for this but by reflecting that objects operate upon the mind and break or interrupt the continuity of its actions not according to their real greatness but according to their proportion to each other. And therefore, since this interruption makes an object cease to appear the same, it must be the uninterrupted progress of the thought which constitutes the imperfect identity. This may be confirmed by another phenomenon. A change in any considerable part of a body destroys its identity but it is remarkable that where the change is produced gradually and insensibly we are less apt to ascribe to it the same effect. The reason can plainly be no other than that the mind, in following the successive changes of the body, feels an easy passage from the surveying its condition in one moment to the viewing of it in another, and at no particular time perceives any interruption in its actions, from which continued perception it ascribes a continued existence and identity to the object. But whatever precaution we may use in introducing the changes gradually and making them proportionable to the whole, it is certain that where the changes are at last observed to become considerable we make a scruple of ascribing identity to such different objects. There is, however, another artifice by which we may induce the imagination to advance a step farther, and that is by producing a reference of the parts to each other and a combination to some common end or purpose. A ship of which a considerable part has been changed by frequent reparations is still considered as the same. Or does the difference of the materials hinder us from ascribing an identity to it? The common end in which the parts conspire is the same under all their variations and affords an easy transition of the imagination from one situation of the body to another. But this is still more remarkable when we add a sympathy of parts to their common end and suppose that they bear to each other the reciprocal relation of cause and effect in all their actions and operations. This is the case with all animals and vegetables, where not only the several parts have a reference to some general purpose but also a mutual dependence on and connection with each other. The effect of so strong a relation is that though everyone must allow that in a very few years both vegetables and animals endure a total change, yet we still attribute identity to them while their form, size, and substance are entirely altered. An oak that grows from a small plant to a large tree is still the same oak, though there be not one particle of matter or figure of its parts the same. An infant becomes a man and is sometimes fat, sometimes lean, without any change in his identity. We may also consider the two following phenomena which are remarkable in their kind. The first is that though we commonly be able to distinguish pretty exactly between numerical and specific identity, yet it sometimes happens that we confound them and in our thinking and reasoning employ the one for the other. Thus a man who hears a noise that is frequently interrupted and renewed says it is still the same noise, though it is evident the sounds have only a specific identity or resemblance, and there is nothing numerically the same but the cause which produced them. In like manner it may be said without breach of the propriety of language that such a church which was formerly of brick fell to ruin and that the parish rebuilt the same church of freestone and according to modern architecture. Here neither the form nor materials are the same, nor is there anything common to the two objects but their relation to the inhabitants of the parish, and yet this alone is sufficient to make us denominate them the same. But we must observe that in these cases the first object is in a manner annihilated before the second comes into existence, by which means we are never presented in any one point of time with the idea of difference and multiplicity, and for that reason are less scrupulous in calling them the same. Secondly, we may remark that though in a succession of related objects it be in a manner requisite that the change of parts be not sudden nor entire in order to preserve the identity, yet where the objects are in their nature changeable and inconstant, we admit of a more sudden transition than would otherwise be consistent with that relation. Thus as the nature of a river consists in the motion and change of parts, though in less than four and twenty hours these be totally altered, this hinders not the river from continuing the same during several ages. What is natural and essential to anything is in a manner expected, and what is expected makes less impression and appears of less moment than what is unusual and extraordinary. A considerable change of the former kind seems really less to the imagination than the most trivial alteration of the latter, and by breaking less the continuity of the thought has less influence in destroying the identity. We now proceed to explain the nature of personal identity, which has become so great a question in philosophy, especially of late years in England, where all the abstruser sciences are studied with a peculiar order and application. And here it is evident the same method of reasoning must be continued, which has so successfully explained the identity of plants and animals and ships and houses and of all the compounded and changeable productions either of art or nature. The identity which we ascribe to the mind of man is only a fictitious one, and of a like kind with that which we ascribe to vegetables and animal bodies. It cannot, therefore, have a different origin, but must proceed from a like operation of the imagination upon like objects. But lest this argument should not convince the reader, though in my opinion perfectly decisive, let him weigh the following reasoning which is still closer and more immediate. It is evident that the identity which we attribute to the human mind, however perfect we may imagine it to be, is not able to run the several different perceptions into one and make them lose their characters of distinction and difference which are essential to them. It is still true that every distinct perception which enters into the composition of the mind is a distinct existence, and is different and distinguishable and separable from every other perception, either contemporary or successive. But as notwithstanding this distinction and separability we suppose the whole train of perceptions to be united by identity, a question naturally arises concerning this relation of identity. Whether it be something that really binds our several perceptions together or only associates their ideas in the imagination. That is, in other words, whether in pronouncing concerning the identity of a person we observe some real bond among his perceptions or only feel one among the ideas we form of them. This question we might easily decide if we would recollect what has been already proved at large, that the understanding never observes any real connection among objects and that even the union of cause and effect, when strictly examined, resolves itself into a customary association of ideas. For from thence it evidently follows that identity is nothing really belonging to these different perceptions and uniting them together, but is merely a quality which we attribute to them because of the union of their ideas in the imagination when we reflect upon them. Now the only qualities which can give ideas and union in the imagination are these three relations above mentioned. These are the uniting principles in the ideal world, and without them every distinct object is separable by the mind and may be separately considered, and appears not to have any more connection with any other object than if disjoined by the greatest difference and remoteness. It is therefore on some of these three relations of resemblance, contiguity and causation that identity depends, and as the very essence of these relations consists in their producing an easy transition of ideas, it follows that our notions of personal identity proceed entirely from the smooth and uninterrupted progress of the thought along a train of connected ideas according to the principles above explained. The only question therefore which remains is by what relations this uninterrupted progress of our thought is produced when we consider the successive existence of a mind or thinking person? And here it is evident we must confine ourselves to resemblance and causation, and must drop contiguity, which has little or no influence in the present case. To begin with resemblance, suppose we could see clearly into the breast of another, and observe that succession of perceptions which constitutes his mind or thinking principle, and suppose that he always preserves the memory of a considerable part of past perceptions. It is evident that nothing could more contribute to the bestowing a relation on this succession amidst all its variations. For what is the memory but a faculty by which we raise up the images of past perceptions? And as an image necessarily resembles its object, must not the frequent placing of these resembling perceptions in the chain of thought convey the imagination more easily from one link to another, and make the whole seem like the continuance of one object. In this particular then the memory not only discovers the identity, but also contributes to its production by producing the relation of resemblance among the perceptions. The case is the same whether we consider ourselves or others. As to causation, we may observe that the true idea of the human mind is to consider it as a system of different perceptions or different existences which are linked together by the relation of cause and effect, and mutually produce, destroy, influence, and modify each other. Our impressions give rise to their correspondent ideas, and these ideas in their turn produce other impressions. One thought chases another and draws after it a third, by which it is expelled in its turn. In this respect I cannot compare the soul more properly to anything than to a republic or commonwealth in which the several members are united by the reciprocal ties of government and subordination, and give rise to other persons who propagate the same republic in the incessant changes of its parts. And as the same individual republic may not only change its members but also its laws and constitutions, in like manner the same person may vary his character and disposition as well as his impressions and ideas without losing his identity. Whatever changes he endures, his several parts are still connected by the relation of causation. And in this view our identity with regard to the passions serves to corroborate that with regard to the imagination, by the making our distant perceptions influence each other, and by giving us a present concern for our past or future pains or pleasures. As a memory alone equates us with the continuance and extent of this succession of perceptions, it is to be considered upon that account chiefly as the source of personal identity. Had we no memory we never should have any notion of causation, nor consequently of that chain of causes and effects which constitute our self or person. But having once acquired this notion of causation from the memory we can extend the same chain of causes and consequently the identity of our persons beyond our memory and can comprehend times and circumstances and actions which we have entirely forgot but suppose in general to have existed. For how few of our past actions are there of which we have any memory? Who can tell me, for instance, what were his thoughts and actions on the 1st of January 1715, the 11th of March 1719, and the 3rd of August 1733, or will he affirm because he has entirely forgot the incidents of these days that the present self is not the same person with the self of that time, and by that means overturn all the most established notions of personal identity. In this view, therefore, memory does not so much produce as discover personal identity by shooing us the relation of cause and effect among our different perceptions. It will be incumbent on those who affirm that memory produces entirely our personal identity to give a reason why we can thus extend our identity beyond our memory. The whole of this doctrine leads us to a conclusion which is of great importance in the present affair. That is, that all the nice and subtle questions concerning personal identity can never possibly be decided and are to be regarded rather as grammatical than as philosophical difficulties. Identity depends on the relations of ideas, and these relations produce identity by means of that easy transition they occasion. But as the relations and the easiness of the transition may diminish by insensible degrees, we have no just standard by which we can decide any dispute concerning the time when they acquire or lose a title to the name of identity. All the disputes concerning the identity of connected objects are merely verbal, except so far as the relation of parts gives rise to some fiction or imaginary principle of union as we have already observed. What I have said concerning the first origin and uncertainty of our notion of identity as applied to the human mind may be extended with little or no variation to that of simplicity. An object whose different coexistent parts are bound together by a close relation operates upon the imagination after much the same manner as one perfectly simple and indivisible, and requires not a much greater stretch of thought in order to its conception. From this similarity of operation we attribute a simplicity to it, and feign a principle of union as the support of this simplicity and the center of all the different parts and qualities of the object. Thus we have finished our examination of the several systems of philosophy, both of the intellectual and natural world, and in our miscellaneous way of reasoning have been led into several topics which will either illustrate and confirm some preceding part of this discourse or prepare the way for our following opinions. It is now time to return to a more close examination of our subject and to proceed in the accurate anatomy of human nature, having fully explained the nature of our judgment and understanding. End of File 38. File 39 of A Treatise of Human Nature by David Hume. Volume 1. This LibriVox recording is in the public domain. Recording by George Yeager. Book 1. Part 4. Section 7. Conclusion of this book. But before I launch out into those immense depths of philosophy which lie before me, I find myself inclined to stop a moment in my present station and to ponder that voyage which I have undertaken, and which undoubtedly requires the utmost art and industry to be brought to a happy conclusion. Me thinks I am like a man who, having struck on many shoals and having narrowly escaped shipwreck in passing a small frith, has yet the temerity to put out to sea in the same leaky weather-beaten vessel, and even carries his ambition so far as to think of compassing the globe under these disadvantageous circumstances. My memory of past errors and perplexities makes me diffident for the future. The wretched condition, weakness, and disorder of the faculties I must employ in my inquiries increase my apprehensions. And the impossibility of amending or correcting these faculties reduces me almost to despair, and makes me resolve to perish on the barren rock on which I am at present, rather than venture myself upon that boundless ocean which runs out into immensity. This sudden view of my danger strikes me with melancholy, and as it is usual for that passion above all others to indulge itself, I cannot forbear feeding my despair with all those desponding reflections which the present subject furnishes me with in such abundance. I am first affrighted and confounded with that forlorn solitude in which I am placed in my philosophy, and fancy myself some strange uncouth monster who not being able to mingle and unite in society has been expelled all human commerce and left utterly abandoned and disconsolate. Fane would I run into the crowd for shelter and warmth, but cannot prevail with myself to mix with such deformity. I call upon others to join me in order to make a company apart, but no one will hearken to me. Everyone keeps at a distance and dreads that storm which beats upon me from every side. I have exposed myself to the enmity of all metaphysicians, logicians, mathematicians, and even theologians, and can I wonder at the insults I must suffer. I have declared my disapprobation of their systems, and can I be surprised if they should express a hatred of mine and of my person. When I look abroad I foresee on every side dispute, contradiction, anger, colony, and detraction. When I turn my eye inward I find nothing but doubt and ignorance. All the world conspires to oppose and contradict me, though such is my weakness that I feel all my opinions loosen and fall of themselves when unsupported by the approbation of others. Every step I take is with hesitation, and every new reflection makes me dread an error and absurdity in my reasoning. For with what confidence can I venture upon such bold enterprises, when beside those numberless infirmities peculiar to myself I find so many which are common to human nature? Can I be sure that in leaving all established opinions I am following truth, and by what criterion shall I distinguish her even if fortune should at last guide me on her footsteps? After the most accurate and exact of my reasonings I can give no reason why I should assent to it, and feel nothing but a strong propensity to consider objects strongly in that view under which they appear to me. Experience is a principle which instructs me in the several conjunctions of objects for the past. Habit is another principle which determines me to expect the same for the future, and both of them conspiring to operate upon the imagination make me form certain ideas in a more intense and lively manner than others which are not attended with the same advantages. Without this quality by which the mind enlivens some ideas beyond others, which seemingly is so trivial and so little founded on reason, we could never assent to any argument nor carry our view beyond those few objects which are present to our senses. Nay, even to these objects we could never attribute any existence but what was dependent on the senses, and must comprehend them entirely in that succession of perceptions which constitutes our self or person. Nay farther, even with relation to that succession, we could only admit of those perceptions which are immediately present to our consciousness, nor could those lively images with which the memory presents us be ever received as true pictures of past perceptions. The memory, senses, and understanding are, therefore, all of them founded on the imagination or the vivacity of our ideas. No wonder a principle so inconstant and fallacious should lead us into errors when implicitly followed, as it must be, in all its variations. It is this principle which makes us reason from causes and effects, and it is the same principle which convinces us of the continued existence of external objects when absent from the senses. But though these two operations be equally natural and necessary in the human mind, yet in some circumstances they are, see Section 4, directly contrary, nor is it possible for us to reason justly and regularly from causes and effects, and at the same time believe the continued existence of matter. How then shall we adjust those principles together? Which of them shall we prefer? Or in case we prefer neither of them but successively ascent to both, as is usual among philosophers, with what confidence can we afterwards usurp that glorious title when we thus knowingly embrace a manifest contradiction? This contradiction, see Part 3, Section 14, would be more excusable were it compensated by any degree of solidity and satisfaction in the other parts of our reasoning. But the case is quite contrary. When we trace up the human understanding to its first principles, we find it to lead us into such sentiments as seem to turn into ridicule all our past pains and industry, and to discourage us from future inquiries. Nothing is more curiously inquired after by the mind of man than the causes of every phenomenon, nor are we content with knowing the immediate causes, but push on our inquiries till we arrive at the original and ultimate principle. We would not willingly stop before we are acquainted with that energy in the cause by which it operates on its effect, that tie which connects them together, and that efficacious quality on which the tie depends. This is our aim in all our studies and reflections, and how must we be disappointed when we learn that this connection, tie, or energy lies merely in ourselves and is nothing but that determination of the mind which is acquired by custom and causes us to make a transition from an object to its usual attendant, and from the impression of one to the lively idea of the other. Such a discovery not only cuts off all hope of ever attaining satisfaction, but even prevents our very wishes, since it appears that when we say we desire to know the ultimate and operating principle as something which resides in the external object, we either contradict ourselves or talk without a meaning. This deficiency in our ideas is not indeed perceived in common life, nor are we sensible that in the most usual conjunctions of cause and effect we are as ignorant of the ultimate principle which binds them together as in the most unusual and extraordinary. But this proceeds merely from an illusion of the imagination, and the question is how far we ought to yield to these illusions. This question is very difficult and reduces us to a very dangerous dilemma whichever way we answer it. For if we assent to every trivial suggestion of the fancy, beside that these suggestions are often contrary to each other, they lead us into such errors, absurdities, and obscurities that we must at last become ashamed of our credulity. Nothing is more dangerous to reason than the flights of the imagination, and nothing has been the occasion of more mistakes among philosophers. Men of bright fancies may, in this respect, be compared to those angels whom the Scripture represents as covering their eyes with their wings. This has already appeared in so many instances that we may spare ourselves the trouble of enlarging upon it any further. But on the other hand, if the consideration of these instances makes us take a resolution to reject all the trivial suggestions of the fancy, and adhere to the understanding—that is, to the general and more established properties of the imagination—even this resolution, if steadily executed, would be dangerous, and attended with the most fatal consequences. For I have already shown, C. Section 1, that the understanding when it acts alone and according to its most general principles entirely subverts itself and leaves not the lowest degree of evidence in any proposition, either in philosophy or common life. We save ourselves from this total skepticism only by means of that singular and seemingly trivial property of the fancy by which we enter with difficulty into remote views of things and are not able to accompany them with so sensible an impression as we do those which are more easy and natural. Shall we then establish it for a general maxim that no refined or elaborate reasoning is ever to be received? Consider well the consequences of such a principle. By this means you cut off entirely all science and philosophy. You proceed upon one singular quality of the imagination, and by a parity of reason must embrace all of them, and you expressly contradict yourself since this maxim must be built on the preceding reasoning which will be allowed to be sufficiently refined and metaphysical. What party, then, shall we choose among these difficulties? If we embrace this principle and condemn all refined reasoning, we run into the most manifest absurdities. If we reject it in favor of these reasonings, we subvert entirely the human understanding. We have, therefore, no choice left but betwixt a false reason and none at all. For my part I know not what ought to be done in the present case. I can only observe what is commonly done, which is that this difficulty is seldom or never thought of, and even where it has once been present to the mind is quickly forgot, and leaves but a small impression behind it. Very refined reflections have little or no influence upon us, and yet we do not and cannot establish it for a rule that they ought not to have any influence, which implies a manifest contradiction. But what have I here said that reflections very refined and metaphysical have little or no influence upon us? This opinion I can scarce forbear retracting and condemning from my present feeling and experience. The intense view of these manifold contradictions and imperfections in human reason has so wrought upon me and heated my brain that I am ready to reject all belief and reasoning and can look upon no opinion even as more probable or likely than another. Where am I or what? From what causes do I derive my existence, and to what condition shall I return? Whose favor shall I court, and whose anger must I dread? What being surround me, and on whom have I any influence, or who have any influence on me? I am confounded with all these questions and begin to fancy myself in the most deplorable condition imaginable, environed with the deepest darkness and utterly deprived of the use of every member and faculty. Most fortunately it happens that since reason is incapable of dispelling these clouds, nature herself suffices to that purpose, and cures me of this philosophical melancholy and delirium, either by relaxing this bent of mind, or by some avocation and lively impression of my senses which obliterate all these chimeras. I dine, I play a game of backgammon, I converse, and am merry with my friends, and when after three or four hours amusement I would return to these speculations they appear so cold and strained and ridiculous that I cannot find in my heart to enter into them any farther. Here then I find myself absolutely and necessarily determined to live and talk and act like other people in the common affairs of life, but notwithstanding that my natural propensity and the course of my animal spirits and passions reduce me to this indolent belief in the general maxims of the world, I still feel such remains of my former disposition that I am ready to throw all my books and papers into the fire, and resolve nevermore to renounce the pleasures of life for the sake of reasoning and philosophy. For those are my sentiments in that splenetic humor which governs me at present. I may, nay, I must yield to the current of nature in submitting to my senses and understanding, and in this blind submission I shoot most perfectly my sceptical disposition and principles. But does it follow that I must strive against the current of nature which leads me to indolence and pleasure, that I must seclude myself in some measure from the commerce and society of men, which is so agreeable, and that I must torture my brains with subtleties and sophistries at the very time that I cannot satisfy myself concerning the reasonableness of so painful an application, nor have any tolerable prospect of arriving by its means at truth and certainty? Under what obligation do I lie of making such an abuse of time? And to what end can it serve either for the service of mankind or for my own private interest? No, if I must be a fool, as all those who reason or believe anything certainly are, my follies shall at least be natural and agreeable. Where I strive against my inclination, I shall have a good reason for my resistance, and will no more be led a wandering into such dreary solitudes and rough passages as I have hitherto met with. These are the sentiments of my spleen and indolence, and indeed I must confess that philosophy has nothing to oppose to them, and expects a victory more from the returns of a serious good-humored disposition than from the force of reason and conviction. In all the incidents of life, we ought still to preserve our skepticism. If we believe that fire warms or water refreshes, it is only because it costs us too much pains to think otherwise. Nay, if we are philosophers, it ought only to be upon skeptical principles and from an inclination which we feel to the employing ourselves after that manner. Where reason is lively and mixes itself with some propensity, it ought to be assented to. Where it does not, it never can have any title to operate upon us. At the time, therefore, that I am tired with amusement and company, and have indulged a reverie in my chamber or in a solitary walk by a riverside, I feel my mind all collected within itself, and am naturally inclined to carry my view into all those subjects about which I have met with so many disputes in the course of my reading and conversation. I cannot forbear having a curiosity to be acquainted with the principles of moral, good and evil, the nature and foundation of government, and the cause of those several passions and inclinations which actuate and govern me. I am uneasy to think I approve of one object and disapprove of another, call one thing beautiful and another deformed, decide concerning truth and falsehood, reason and folly, without knowing upon what principles I proceed. I am concerned for the condition of the learned world which lies under such a deplorable ignorance in all these particulars. I feel an ambition to arise in me of contributing to the instruction of mankind, and of acquiring a name by my inventions and discoveries. These sentiments spring up naturally in my present disposition, and should I endeavor to banish them by attaching myself to any other business or diversion, I feel I should be a loser in point of pleasure, and this is the origin of my philosophy. But even suppose this curiosity and ambition should not transport me into speculations without the sphere of common life, it would necessarily happen that from my very weakness I must be led into such inquiries. It is certain that superstition is much more bold in its systems and hypotheses than philosophy. And while the latter contents itself with assigning new causes and principles to the phenomena which appear in the visible world, the former opens a world of its own, and presents us with scenes and beings and objects which are altogether new. Since therefore it is almost impossible for the mind of man to rest, like those of beasts, in that narrow circle of objects which are the subject of daily conversation and action, we ought only to deliberate concerning the choice of our guide, and ought to prefer that which is safest and most agreeable. And in this respect, I make bold to recommend philosophy, and shall not scruple to give it the preference to superstition of every kind or denomination. For as superstition arises naturally and easily from the popular opinions of mankind, it seizes more strongly on the mind and is often able to disturb us in the conduct of our lives and actions. Philosophy, on the contrary, if just, can present us only with mild and moderate sentiments, and if false and extravagant, its opinions are merely the objects of a cold and general speculation, and seldom go so far as to interrupt the course of our natural propensities. The cynics are an extraordinary instance of philosophers, who from reasonings purely philosophical ran into as great extravagancies of conduct as any monk or dervish that ever was in the world. Generally speaking, the errors in religion are dangerous. Those in philosophy only ridiculous. I am sensible that these two cases of the strength and weakness of the mind will not comprehend all mankind, and that there are in England in particular, many honest gentlemen who, being always employed in their domestic affairs or amusing themselves in common recreations, have carried their thoughts very little beyond those objects, which are every day exposed to their senses. And indeed, of such as these, I pretend not to make philosophers, nor do I expect them either to be associates in these researches or auditors of these discoveries. They do well to keep themselves in their present situation, and instead of refining them into philosophers, I wish we could communicate to our founders of systems a share of this gross earthy mixture as an ingredient which they commonly stand much in need of, and which would serve to temper those fiery particles of which they are composed. While a warm imagination is allowed to enter into philosophy, and hypotheses embraced merely for being specious and agreeable, we can never have any steady principles nor any sentiments which will suit with common practice and experience. But were these hypotheses once removed, we might hope to establish a system or set of opinions, which if not true, for that perhaps is too much to be hoped for, might at least be satisfactory to the human mind, and might stand the test of the most critical examination. Nor should we despair of attaining this end because of the many comirical systems which have successively arisen and decayed away among men. Would we consider the shortness of that period wherein these questions have been the subjects of inquiry and reasoning? Two thousand years with such long interruptions and under such mighty discouragements are a small space of time to give any tolerable perfection to the sciences, and perhaps we are still in too early an age of the world to discover any principles which will bear the examination of the latest posterity. For my part, my only hope is that I may contribute a little to the advancement of knowledge by giving in some particulars a different turn to the speculations of philosophers, and pointing out to them more distinctly those subjects where alone they can expect assurance and conviction. Human nature is the only science of man, and yet has been hitherto the most neglected. It will be sufficient for me if I can bring it a little more into fashion, and the hope of this serves to compose my temper from that spleen, and invigorate it from that indolence which sometimes prevail upon me. If the reader finds himself in the same easy disposition, let him follow me in my future speculations. If not, let him follow his inclination and wait the returns of application and good humor. The conduct of a man who studies philosophy in this careless manner is more truly skeptical than that of one who feeling in himself an inclination to it is yet so overwhelmed with doubts and scruples as totally to reject it. A true skeptic will be diffident of his philosophical doubts as well as of his philosophical conviction, and will never refuse any innocent satisfaction which offers itself upon account of either of them. Nor is it only proper we should in general indulge our inclination in the most elaborate philosophical researches, notwithstanding our skeptical principles, but also that we should yield to that propensity which inclines us to be positive and certain in particular points according to the light in which we survey them in any particular instant. It is easier to forbear all examination and inquiry than to check ourselves in so natural a propensity and guard against that assurance which always arises from an exact and full survey of an object. On such an occasion we are apt not only to forget our skepticism, but even our modesty too, and make use of such terms as these, it is evident, it is certain, it is undeniable, which I do deference to the public ought, perhaps, to prevent. I may have fallen into this fault after the example of others, but I here enter a caveat against any objections which may be offered on that head, and declare that such expressions were extorted from me by the present view of the object, and imply no dogmatical spirit nor conceited idea of my own judgment, which are sentiments that I am sensible can become nobody, and a skeptic still less than any other. End of File 39. End of A Treatise of Human Nature, Volume 1, by David Hume


I'm Carol Christ, I'm the Chancellor of UC Berkeley. Welcome to the first of this year's 111th annual Martin Meyerson Berkeley Faculty Research Lectures. For more than a century, Berkeley's Academic Senate has singled out distinguished members of our faculty whose research has changed the trajectory of their disciplines and of our understanding of the subject they've dedicated their careers to. These lectures shine a light on an essential part of our mission which is creating new knowledge. The curiosity and the creativity that fuel the quest to learn and understand are at the heart of our commitment to making the world a better place. So what we through what we discover, what we teach and the public service we provide. This year's lectures represent the continuation of a treasured tradition that is recurred annually with one exception. In the wake of World War I and the influenza pandemic, the faculty research lectures were suspended in 1919. In 2020, when virtual events were in vogue and Zoom kept us together, the lectures went on. Being selected to deliver a faculty research lecture is rightfully seen as a high honor. The peers who exemplify academic excellence is no small feat. For students, members of the campus community and the public, this is a wonderful way of experiencing scholarly research of the highest caliber. I'd like now to welcome the past recipients who are with us today. Professors, please stand when I read your name and let's hold our applause until everyone has been recognized. Walter Alvarez, Bill Dietrich, Catherine Gallagher, Robert Haas, Barbara Romanois, Montgomery Slotkin and Marty Jay. Please give them a round of applause. The two individuals chosen to give this year's faculty research lectures are Inez Fung and Michael Nyland who is presenting in May. Inez is a professor of Earth and Planetary Science and of Environmental Science Policy and Management. She models the processes that maintain and alter the composition of the atmosphere and as a consequence, the climate. Dr. Fung received degrees in applied mathematics and meteorology from MIT and was the founding director of the Berkeley Center for Atmospheric Sciences. She's the subject of Forecast Earth, part of a series of books on women scientists for middle schoolers that was launched by the National Academy of Sciences. She was also featured in a YouTube video sponsored by Wired Magazine called What Could Happen in a World That's Four Degrees Warmer. This is in addition to her multitudinous scientific publications. Please join me in welcoming Professor Inez Fung whose lecture is titled On the CO2 Trail. Thank you. Thank you so very, very much for this great honor. CO2, I don't think I need to introduce people to CO2. This is a familiar figure, the increase of CO2 in the atmosphere. I put in lines, this is when I arrived at Berkeley in 1998 and CO2 and you can see how much the CO2 has increased in the last 25 years.  Okay, so when we have some warming from the CO2, then there's increased evaporation from the ocean. And so that enhances, okay, this is what we do in freshman class, so CO2 does this, okay, at the right wavelength, okay, and water can do more, okay, then more water and they get more excited and then they bump into the nitrogen and oxygen. So here then with the body, water vapor, then there's an additional warming from the water vapor and similarly, melting snow and ice, the surface is darker and so that absorbs more sunlight and so that also amplifies the warming. We used to call this positive feedback and positive is something you want and so this is not, okay, so where the dial is, is in the clouds, okay, so if we have more clouds, if that low clouds, they reflect sunlight and so it will be cooling, I'm from the tropics, we like cumulonimbus clouds, so they radiate out at a cooler temperature, colder temperature, so they could, there would be less, there would be warming. So here CO2 always travels with water. So when we look at the CO2 increase, this is a figure of the global fossil fuel emission, you can see the steady trend. So we have OPEC here of Iran, change of regime in Iran, dissolution of the Soviet Union and then the financial crisis and the COVID pandemic. So even though we have changed our driving habits, we have the economy slowed down, you can see the recovery, that is a minor dip, okay, we still, even though we're not driving, we're still consuming food, we are still heating our houses using our computers, et cetera. So when we look at the increase, the top, the green is the fossil fuel in CO2 and the blue is what is in the atmosphere. So you can see the green part has gone somewhere, okay, there's no way to go on that time scale except the land and the ocean. So early on in my career, I use the atmosphere, I'm a atmospheric scientist, okay, so then you can see at Monalua, the CO2 is higher than that at South Pole. So we have data since 1957, the International Geophysical Year. So it's always about 1% higher, okay, so Monalua is always higher because the atmosphere mixes. So the mixing time is about one year. So when we do the model and say, if I put in fossil fuel CO2, then the gradient, the hemispheric gradient is too large. So the only way to explain the observed hemispheric gradient, given there are observations over the land, is to put it, over the ocean, is to put it on land. Man, that was difficult. People didn't like that. Okay, but here now, many decades later, we have enough observations so that we can say that the atmosphere takes about approximately 50% and the land and ocean 25% is fairly democratic. But what is interesting here to me is that the little red bars, okay, so these are El Nino years. So some El Nino years, the hemispheric increase is very small and the land and ocean take up a lot of CO2 from the atmosphere, whereas other years is the opposite. So the question is, when the climate continues to warm, what would happen? So when I came to Berkeley, I was serving on the International Geosphere Biosphere Program and we thought that it was time to have a joint project with the world climate research program. So basically the fluid dynamicists and the physicists on one side and the biogeochemists, the chemists and the biologists on the other side. So I had the shortest flight, if that could be said, from here to Melbourne to meet with the climate modeling guys on the weekend. And so after much back and forth, we proposed, they agreed that this would be what we do. So we specify fossil fuel in the, instead of specifying CO2 increase in the atmosphere, which is what had been what we were doing before, we specify the fossil fuel into the atmosphere, we put in the ocean carbon and the interactive land carbon and let the atmosphere take the residual, okay? So I call this, we call it because it's never been done before, I call that the flying leap experiment and our password was splat. So here, so it's not respectable. So now it's called the, it's now called the couple carbon cycle climate model in the comparison, C4-MIP, okay? But I still think of it as flying leap. Okay, so splat, here we go, splat. So here we had many models, we had the same fossil fuel emission and BYO-M means bring your own model, okay? So it was the first one we did, okay? So you can see here between, this is the difference, okay? When we had, instead of just doing carbon cycle the same climate, we put in the climate and carbon to interact and evolve together and this is the difference, okay? So you can see the difference is huge. All models say that when we put in, when we have the interaction between the changing climate, then there's more CO2 in the atmosphere, okay? We call that the warming feeds the warming, okay? But the difference here is that Peter Cox with the Hadley Center model and he, his model was very, I call that the prima donna model, okay? Very excited hydrologic cycle. So he had droughts in the Amazon and he killed all the trees and then immediately there's decomposition and so he had a high CO2 whereas I'm on the other end. My trees suffered quietly. Okay, so the thing is why is, this is huge, okay? 300 parts per million is huge, okay? And this is just the feedback. So when I look at my model you can just look at the, when I look at my own calculation you can see the red part. This is the correlation between temperature and soil moisture, okay? So in the tropics it's green, it's negative. That means that when it is warmer the tropic gets drier and at high latitudes in the winter and somewhat in the summer when it is warmer the soil is wetter, okay? So with the Hadley Center model, the prima donna model they collapse the rainforest to kill all the trees, okay? And mine was there. So, you know, you can see I'm competitive. I'm going after Peter Cox, okay? But the thing is here, soil moisture, you can look at this, this is old time, okay? This is a while ago from the last century. So you can see from the model projection the stippling is 80% of the models agree in sign, okay? So yes, we have wetter tropics and here may be drying and wetter in the high latitudes but you look at soil moisture, we don't really agree, okay? We don't, and forget about runoff, okay? Evaporation, yes, when it is warmer my laundry dries faster, okay? So yes, we agree on evaporation. So what do I do, okay?  So what we did was make a proposal for a new measurement program. And so this is to the CAC Foundation. And every time I look at this, I'm so grateful that we were selected, okay? So we wrote that precipitation in stream flow represent the excess water that the atmosphere and soils cannot hold. So measurement of these surpluses do not tell us anything about the processes, okay? And then Jim Kirchner, who was part of the whole team wrote that using the today's hydrologic measurement tools is comparable to listening to a Beethoven symphony but hearing a note every minute, okay? So what we're doing is, we were grateful we were selected, is that we had, so we started a project, hydro watch at the Eel River watershed at the Angelo Coast Range Reserve, Mary Power who's here is the faculty director and Bill Dietrich who's here, he's been working there. And I want to say right now I am a couch potato, I don't, I'm afraid of heights, okay? So you don't see me in the field very often but here you can see here close to Mendocino Coast. Okay, so we have the hydro watch and so it's on a steep, very steep terrain. And you can see here from Bill Dietrich's, the laser mapping, here's the topography and Bill Dietrich called it Rivendell, okay? So many of you know Rivendell. So here's the creek, this is the Lidar image with the creek, okay? So here, Jim Bishop took these pictures. So here's the creek at the bottom, there's water samplers and I want you to see the ladders that go up, okay? You don't see any pictures of me on the ladders and so keep going up and up.  And then once you get on the other ladder, you have to walk like this and then more ladders, et cetera, et cetera, et cetera. Okay, so what we did was at this site and this is new at the time. Okay, 4,000 square meters, we put in and I counted and Bill probably can tell me a different number, but over 1,000 sensors, okay, at this site. We put it on Wi-Fi backbone, okay? And we put in our own solar panels and we set up a data system, okay? So that the sensors will monitor everything, the soil moisture, the sap flow, the chemistry in the water, the rain gauge, and then the well, the water table, et cetera, okay? All of that will come, will beam home every day, okay? So we can see the, we can see the data. So at the time, this is new. So here I'm gonna start talking about the sap velocity data. This is together, I want to say again, I don't do any fieldwork. So this is with Todd Dawson teaching student, teaching student Percy Link. And so you can see here the, you put a probe into the tree and so the middle probe sends out a heat pulse. And so when the water goes through, you can tell the temperature difference and you can see how fast the water's going. So then, so this is, so Percy Link, I mean, it's too dark, but you can see Percy here. So we started with evergreen species, Douglas fir, bay, life oak, et cetera. And so here is the creek and here's the slope going up. And so what we, so we expect that all these are evergreen trees that they have the same seasonal cycle. They transpire, they take water at the same time. And so we have 25 trees, 53 sensors. And we have multi-year, four or so years, three years here of 30 minute frequency data, okay? All beamed home at real time. So I don't need to go through California's summer, dry summer, wet winter, and intermediate seasons. So when we look at the sap velocities, then what you see here, the Douglas firs, okay, have a slow decline during the dry summer and then as soon as the rains come, here we are, okay? The sap velocity picks up. Madrones are very strange. They have their maximum transpiration in the dry summer, okay? And then a slow ramp up, okay, and slow decline and life oak is what I'm saying, steady up, steady increase and steady decrease during the seasons. So the madrone during COVID, we were stuck at Friday Harbor and I walked around every day. So now I understand why madrones do that. They leave the lifetime of the leaves 14 months and they overlap, okay? So you can see here the old leaves here and the new leaves and then they have flowers and that's when all the transpiration, all the water use happens. So then we decided to continue and so Aaron Belize PhD thesis, we only did madrones in the dry summer. So this is California dry summer but we did them on the North Slope and the South Slope. Okay, North Slope. So you can't see the, I don't think you can see the difference but you can see the transpiration between the two slopes. And what was the surprise here is that during the dry summer, the South Slope trees transpire more water than the North Slope trees, okay? We checked, it's just not, you know, everything we checked. So this is not an artifact of anything and so we had several summers. And so our hypothesis here, now this is getting into a little bit of science fiction on my part, is that the North Slope, we call the North Slope trees are profligate water users. Okay, they don't have enough sunlight, okay? So when there's sunlight, they have a lot of water, okay? So then they can use, they don't care, okay? As soon as there's sunlight, okay, whereas the South Slope trees in the North, so hot and dry and so they are, they're much more efficient water users, okay? But this raises the issue when I'm thinking about climate, about adaptation, okay? Why do some trees, this is the same tree species. You can take a look at them and they look the same, okay? But why are they doing, so they have adapted to the new environment. So where do the trees come from, get their water? So this is Bill Dietrich's photo, so we drilled wells to access the groundwater. So here you can see on the slope, I showed you, we drilled this mixed Swiss cheese out of the hill slope. So we have wells and this is going up the slope and I'm gonna show you some data of the wells and the well number increases up slope, okay? So here you can see the date, you can see the data here. Rain on top is the rain. So here the colors, well one is this one and well 10 the red guy is here and note that the depth of the water table is 20 meters, 20 meters down, okay? So here you can see not the well by the creek but the other guys when it rains, okay? The water table goes up by a meter or so or more, okay? And then there's slow drainage in the summer and then the winter rains come. So what does that tell you? It is not a slow percolation of water through, okay? There's secret passages here, okay? Fractures in the bedrock. And so all years we see that. And so what Mikhail did was to do a mathematical model of hydraulic conductivity. The crucial thing here, you can't see this, is that we make the variants dependent on the soil moisture, on the rock moisture itself. So when the soil, when the column is soil column, the rock column is filled with water and then the variance is zero. When it is dry, okay? Then there are many choices to go. The water has many options, okay? So then the variance is large. And so you can see here the modeling of this. And so you can see how the water comes down, okay? So when we have the fractures, when we have that, and this is 20 meters down, okay? So you can imagine when it rains, the water goes, I kept saying secret passages, okay? The fractures where the water goes down. And the way it is done is that when it is wetter, it is easier for the water to go down. So you can see here it's not too bad, okay? Here's the red is the observed water table. We're pretty good on that. I won't show you the whole, I won't have time to show you the whole movie. But you can see the entire record having fractures and having, oops, excess. So what Bill Dietrich calls rock moisture when we integrate over the column is about 30% above the water table. 30% of the water is in the rocks. When we do a sensitivity calculation about how plants excess that water, then it's always the little, so when you have plant roots that are like 10 meters deep, most of the mass is in the upper four meters, 90% of the mass is in the upper four meters and it's the little bit below that can excess the rock moisture, okay? So it's always the little guy that that's all the work. Okay, so now I go to the California drought, okay? So when we come back to the well data, then what we see is that during the drought, this period, the drought period, there's no evidence in any, if you look at the water table, you don't think that there's a drought, okay? Only in the precipitation that we know there's a drought. So since I'm still after Peter Cox in his model where he killed trees, okay? That's why I'm going this way. So what I did was I mapped the forest, the US forestry inventory, the FIA database. So it's required by law, the Department of Agriculture's required by law in 1990 something to measure every tree in the USA, okay? So then they have not every tree, but then they have a protocol of how to sample the tree, et cetera, et cetera, et cetera, okay? And so the data about the tree size, tree height and then there could be some information about the mortality. This came in for California, came in 50 spreadsheets. Anyway, so here are the forests. So for California, for the period, so the data actually started in 2000, so the survey, not all the trees, but the tree surveyed about 330,000, 98 tree species in California. So when I map them according to species, you cannot, so here, you know, it's all familiar to all your hikers, right? That the Douglas first in the coast and there's some up in the Sears, the ponderosa pine here, the incense cedar, okay? They're different habitats for different tree species. But when I look at the FIA database and the mortality of the different tree species, and here I put in the reference period because I don't have time, you know, the data's only started in 2000, so I picked a period that is sort of normal precipitation, sort of, and so then you can see the difference that during the drought, which is in the red, that the tree mortality is higher for every tree species. Okay, some already there's even in the reference, what I call the reference period, high mortality, but this drought and increase the mortality fraction. So, but when I go, since I'm a meteorologist, okay, you look at all the heat, okay, whatever heat index, moisture deficit index, anything. Yes, when there's in hot and dry, some trees die, but I cannot explain the differential mortality across all the tree species. So, so I got stuck, and so I'm really grateful to Nick, who is down the hall from me, Nick Swanson-Hicel, and he pointed me to the geologic map of California. Geology is something I've always been afraid of, so thank you, Nick. You need to spell, okay, so, so, so here you can see the different rock types, but at the end of the day, we grouped them into sedimentary rock, okay, porous rock and volcanic rock and plutonic rock, and Nick told me, helped me to think plutonic rock is like my kitchen counter, okay, not very porous, whereas here the volcanic rocks, here the volcanic rocks, there's an aquifer underneath, so it's very porous rock compared to the sedimentary rocks. So, when I do the same eight tree species, same in the same location, plotted in the same location, there's a reason why I did that, you can see the trees in the top row are more, they're more of them on sedimentary rock, this is sedimentary rock, here's volcanic rock in the middle, plutonic rock here, these are more prevalent on sedimentary rocks, whereas the one in the lower, the bottom row are more prevalent on volcanic or plutonic rocks, okay, so guess how the mortality happens. So, when I look at the same thing, you have seen these figures before, then the trees on the sedimentary rocks are here and the mortality is low, okay, whereas these on the volcanic rocks or on the plutonic rocks, there's high mortality, okay. So, when I go and this is, I don't have data, so I have to go to the horticultural data to look at plant rooting system, okay, so the sedimentary Douglas fir on the coast, they have tap roots, they can tap into the rock moisture, whereas the other trees, the white fir, for example, have shallow roots, okay, so then it is really talking about which trees survive, which trees do well, part of it is rainfall, okay, but a lot of it is where they hang out and that is depending on the geology. So, this is tough to follow, but anyways, the same thing, so I map them, so the circle is the size, so just take a look at this, so this axis is precipitation anomaly, so to the left is drier, and so this is, up is more greater mortality, and so this is for sedimentary rock, plutonic rock in red and volcanic rock in blue, so what you would expect without looking at all of that is that you know, before I looked at the geology, is that here drier is to the left and mortality is higher mortality, I would expect a trend like this, okay, that higher drier with greater mortality, but when I look at them species by species, it is a surprising result that it seems like, and I highlighted this, that the trees on volcanic rocks don't do so well. This is where I'm sort of trying to figure out where to go next, okay, so the hypothesis here is a Goldilocks problem, okay, so on volcanic rocks, the water goes through so fast and there's not, okay, whatever is there just runs away, so the trees don't have access to the water, and so on plutonic rocks, there's not much storage anyway, okay, so it's drier, so the best place is for the sedimentary rocks on the coast and you can see from the mortality, okay, but you know, I started with CO2 and the climate and all of that, why do I, why am I doing this, not just because I'm after Peter Cox, but the question is, the question is, you know, we talk about a forestation as a climate mitigation strategy, it's not just planting trees, okay, what trees do we plant, where do we plant them, where is the water and who can have access to that secret compartment down there, okay, to access that water to survive the drought, okay, I think there's a lot of work to be done in that regard, and so when I look forward, okay, going back again to a forestation, then Abyssal's PhD thesis where we put in, we just say, okay, we're gonna plant trees everywhere at Milatitudes where trees are not, okay, so what happened there is that yes, it got darker, but where trees are not is where there is not enough water to have trees, okay, so what happened to the energy balance, the energy balance shifts, so instead of cooling, okay, this energy balance goes to sensible heat so it warms up the entire northern hemisphere, right, because we planted, nobody would do that, okay, but this is a warning, when we did it at High Latitudes, when we planted trees at High Latitudes, because the High Latitudes, there's very little water vapor, so then the transpiration from the trees enhanced the greenhouse effect, okay, and so we melted the sea ice, we have more evaporation from the open ocean, and so there's a feedback, okay, so yes, planting trees is always good, okay, I want to say that, planting trees is always good, but as a climate mitigation effort, then we have to remember that there's always transpiration, okay, CO2 always travels with the body water, okay, so there's always transpiration, and so there could be warming, okay, so it could be a local strategy where we have enough water on timescales of years, but it's not a long-term solution, okay, because ecosystems saturate, okay, high school kids grow, you feed them, you grow, okay, and then there's a steady state where the input is equal to the output, the photosynthesis is balanced by the decomposition and you're not sequestering carbon anymore, so where are we, okay, so in the global scale, okay, I said up for a station is not a solution, it's not a global solution, it could be a local temporary band-aid, it's always good for other reasons, so here is where we are in the USA in terms of net greenhouse gas emissions. President Biden has set a target for net zero by 2050, okay, so here is what we have, so this is, forget about this, this is the previous administration, so this is the target for the US at the United Nations Conference of Parties, so this is our nationally determined contribution, and so with the President Biden has put in the Inflation Reduction Act and the Climate Bill there, there's a lot of funding for technology to reduce emissions from the oil and gas, from the oil and gas sector, and funding for agriculture to have climate smart agriculture, et cetera, et cetera, and so here is the goal, this is what the President's policies so far have done, and here we have the, if we include what EPA is proposing and what the proposals on the table and state efforts and local efforts that there is a chance that we can meet the target that we promised, so what I've done in the last year, two years, I'm a member of President Biden's Council of Advices on Science and Technology, and this is what I worked on for the last long time, and especially over Christmas here, so this is, so it's one thing for the President to put out a lot of money to take the transition to out of fossil fuel to renewable energy, and it is great that everyone promises to do, yes, we will reduce this and that, so but how do we know, okay, how do we know it's something that we've never done before, how do we know this is, what is the best way to reduce, what is the most effective way, what is the best way to use the money, okay, and how do we invest, okay, the inflation reduction act money is for 10 years, how do we go beyond that, how do we put in the observations, the satellite observations, the ground-based observations, you don't need to read all the recommendations, so we wrote a proposal, so we wrote the report, I've never done a report that starts with Dear Mr. President, but anyway, so we wrote a report and so basically a lot, you cannot do policy, you cannot do without the data, okay, so here we are advocating, recommending that we have wide, not just atmospheric CO2 satellite data that can track small satellites and ground-based observations, more flux towers, et cetera, and healthy soils, okay, but to have the data to monitor everything, so I'll end here, it's very difficult, this is the most difficult slide for me because it has been such a pleasure and privilege to be at Berkeley, when I came, it was a surprise to me since I was at NASA and at Columbia and other places before that there are women in leadership positions, I was not the only one, nobody's there, well, anyway, and there are people from all around the world and so I felt like I belonged and then I'm also grateful to all my colleagues here who have led me into new territories, who have answered questions and taken my students to teach them and teach me new things, so it's been very exciting thing for me and this honor, I cannot thank you enough, so this is, I think we're at an exciting time in terms of the climate that we are actually, you know, the stone age ended not because we ran out of stone, so it's time for us to move, okay, out of the fossil fuel era, okay, into something, into a renewable, into a new energy source, so thank you very much. Any questions for Professor Fung? Raymond. Thank you so much, you know, it's always great to hear your overview. I wonder on this last point, if you might like to opine on the relative roles of government versus the private sector in monitoring the planet in the future, looking forward, there's some hints of that and I wanted to give you a chance to elaborate more on everything from satellite observations to otherwise, how much can the private sector and even private citizens contribute to this? Thank you. Well, to start, I think that the future, all of us, we have to include everybody every way that we can do, so we are seeing small satellites from the private sector, from the state of California is supporting some small satellite measurements and that's in the private sector. And so, and NASA, obviously, we are familiar with the NASA satellite observations. The NASA satellites, the historical, and it's always available, okay, by decree, you can access all satellites that are NASA satellites and you can access the data every time they have an improvement in the calibration, they have an improvement, so you have a sense of the data quality. What we're talking about now with the private sector is that we are recommending in one of those recommendations is that we set up a metric for determining what is quality data, okay? It is important to recognize that regulatory data is not the same as scientific data because all they need is an exceedance, okay? They see a plume, okay? And they see a plume in the private sector. Satellite guys would say data latency is 90 days, okay? So that I could check my calibration and I can do my QAQC, but basically they have privates, they have a business model of which I respect, okay? That they have a business model, they have subscribers who want that data, okay? They want to turn off whatever is emitting before EPA comes to find them, okay? So there's a different model, but we are working to figure out the way to have a national, we're recommending, one of the things we're recommending is a national greenhouse gas center that would oversee all the agencies that would set up the standards, okay? So everybody could be included. And this includes not just the satellite data, but also ground-based data, okay? Now we call instead of top-down data and bottom-up data, we call atmospheric data and activity-based data, okay? So we are recommending not just the expansion, but what is also very important is the expansion of the measurements to disadvantaged communities. In the four corners, I forget how many, 40,000 wells, some large number of wells, a quarter of them are in San Juan County in New Mexico and the tribal people live within half a mile of a well. Okay, so you can imagine what happens to their health and in agricultural systems where we have concentrated agricultural feeding operations, it's not just the feeding, it's not just the methane from the cattle, but also the waste, okay? And the people living next to them. So we are recommending to the president not just the standard satellites, but also ground-based, including the people who are affected so that they have the data to advocate for themselves. That's a very long answer, yes? Yes, thank you. The last slide you're interested to make, of course, is us who will view that for how much you've been rich the campus in your presence here. Well, thank you. The question is, in your recommendation slides, I noticed that you focused a lot on methane. And I'm wondering, is that because we know the unknowns for CO2 and don't know the unknowns for methane? No, no, no, no, no, no. It is not that, the U.S. at COP 26, which is two years ago, the European Union and the U.S. have a global methane pledge. So methane, for molecule, is a much more, you know, it has, okay, it has more excited states. So the methane, it's a much more potent greenhouse gas, but also methane in the atmosphere reacts with OH to form CO2 and water vapor. And so the lifetime is 10 years. So the idea is that the CO2, we are not yet ready to have things at scale to get rid of fossil fuels. We will be dependent on fossil fuels for a while. Okay, so methane is, if you will, a band-aid. And the other thing is methane loss from the oil and gas industry, from the cattle industry, is money loss to the atmosphere. Okay, so it is easier to get a buy-in. So it's trying to say surgically, you know, what can we do, okay, while we work on the bigger problem, okay, and if you look at the Inflation Reduction Act, where the money's going, then there's the big problem, but there's an immediate thing that we can do, okay, to reduce the methane and the industries are on board. We have the satellites now flying in 2024. We will have two small satellites that will be measuring methane. And so in addition to the industries, the agricultural sector, et cetera, and oil and gas sector working on it, that's something that will buy us time. Yeah, there's a band-aid. Yeah. In the back. Hi, Inez, thanks for a good talk. So I'm one of Raymond's students, so I'm also an EPS with you. And I'm wondering if you are starting your PhD now with all this information and new technology, what would you work on, or what big questions would you go after? I would say for all the students, is to, your PhD now, especially at this marvelous school, is to build the base, okay? Take courses in anything, everything that's related to you, rather than, yes, there is, you have always the big question. But if you are so smart, you solve the big question, then what's next, okay? So the suggestion I tell all students is to build your base. Yes, you sort of in a certain direction, but build your base so that when problems change, you are flexible enough to pick up new things and address those new problems. I said I was trained in mathematics, and my PhD was in theoretical geophysical fluid dynamics. So going to the field is something I never thought I would do, and learning geology with all those big words was something I never thought I would do, but I'm really grateful to all my colleagues who would let me, who would teach me and have the patience to put up with my questions. So I think the important thing is that the problems, you're not just doing your PhD, you are preparing for the future, and I don't know where the problems are. Thank you so much for your great presentation. I was wondering, you talked a lot about groundwater aquifers and their importance in sustaining tree cover. Do we find that fossil fuel extraction techniques negatively affect that kind of Goldilocks zone you were talking about with groundwater retention? Yeah, I cannot answer that question yet. I've just started a new project on groundwater. So we are learning about groundwater is the next big problem in the same way. I worked on the climate models. I'm going to say 40 years ago, and I'm going to say everything that we worked on, we said 40 years ago is still valid. Okay, nobody listened to us, says, oh, physics, okay, who cares, right? So now the data are there. So we think that groundwater may be the same with the next big problem is the availability of fresh water, food security, and all those issues and what science we have to do now. I cannot answer your question yet, but I think the science is not totally there to understand the water and the pumping. And then it's not just that, say the Central Valley, there's the natural arsenic and in Kansas, there's the uranium, there's natural, okay? And that impacts, that's in the groundwater in addition to all the other, the nitrates and other stuff.  Yeah, so I didn't know the state of Nebraska has 120,000 wells that drills into the Ocalala, aquifer, so if a Tuesday is with most wells, one is California, one is Nebraska, but California draws more water than Nebraska, so anyway. Thank you for the excellent talk. I'm wondering if you could reflect on a possibility that I don't have the technical expertise to assess, but our colleague, Eli Blanovich, proposed in PNAS last year that one way to get carbon out of the air is to sequester it agriculturally, like you mentioned that as soon as the plants reach adulthood, then they have to decay and all. His idea is to bury it underground in large durable plastic and make sure that it's desiccated so that even anaerobic bacteria don't and the plastic can stay like hundreds of years and so forth as a form of carbon sequestration that's like better than many of them. Does that seem plausible to you? Just generally, have you heard about this? I have heard about many strategies and that is one of them. Some of the strategies would put them in the sea, et cetera, but it's like taking aspirin or something, right? So I cannot see how it would be difficult to imagine how to deploy that at scale, okay? Ask the students how to take one PPM out of the atmosphere, okay? I don't know how to take one PPM out of the, you know? So there is no single silver bullet, okay? So it has to be everything working together, but the more important thing is not the removal but putting less into the atmosphere, okay? And so I think finally what I showed here is that we hope that with the Inflation Reduction Act and the activities that have stimulated that we will be working a lot more on the reduction of the input side, okay? So I'm not saying anything about, I'm for all strategies because we don't know which one would work and which one could be deployed at scale, yeah. I think we are out of time so I'm gonna pass the mic back to Chancellor Christ. Well, and thank you for the splendid lecture or thanks go to you for both your research and just, you know, this wonderful window into your research that you gave us today. So thank you very, very much. Thank you. And please come back to the next faculty research lecture. Thank you.


Hello everyone and welcome. My name is Melissa Armo and today I'm going to talk to you about having goals. Having goals is extremely important. A lot of people want to wait till everything is lined up perfectly in their life before they take any action towards whatever their goals are. It's great to have goals and it's important to have goals. It's important to have dreams. But if you're trying to achieve a certain goal, then you have to take steps towards that.  You have all the time in the world and all the money in the world. All these things lined up that you can take the time to learn how to do whatever it is you want to do. In the case right now, I'm going to discuss about trading because I talked to a lot of people and they say, well, I don't have time. Well, I'm going to wait till I'm retired. I'll wait till this. I'll wait till that time never comes. If you're looking for the absolute perfect, perfect time, the perfect time is now. Because if you have goals in life, it's a process to achieve those goals and you have to take the necessary steps towards that. Get on the right path. You'll feel better about yourself. You'll feel more confident. You'll know that you're on the right path to achieving those goals rather than continually putting it farther and farther and farther out of your reach. And ultimately, they're never getting there. It's really hard to believe, but more than half the year of 2018 is over. Before you know it, it's going to be the holidays and then it will be 2019. And I have talked to so many people and it's really, I'm shocked. I've talked to people recently that have been following me, that have reached out to me, that have been following me for six years and have never taken my class. And I'm astounded by that. Just shocked. And I say to myself, everyone wants everything to be perfect before they move forward in their life, but that's not how you actually move forward. Perfection is in the moment. It's in the now by trusting yourself, trusting the process of life, trusting your own intuition to move forward. If in fact, this is what you want to do. Now, I don't know. That's a choice for you. If you don't want to trade the market or if you don't want to trade the market, that's a choice for you an individual choice. But I've spoken to so many people recently that really want to trade the market and they're putting off this goal, this achievement, this dream, they're not even getting on the path or they're not on the right path and they know it. They know it. So trust me when I say, when you have something out there that you want to achieve, a goal, a dream, whatever you want to call it, you have to start taking steps towards that. Baby steps, small steps, medium steps, big steps, you'll find as soon as you start to proceed, things will just come together. It's like, it's like when something's just meant to be like things just seem to come together. You may not know how it's all going to come together. You may not be able to see how it's all going to come together. But when you trust, trusting yourself, trusting the process of life, I'm telling you, things find a way where they're meant to happen when it's meant to be. It's called destiny if you want, and they just fit and they come together. But people that are stuff that can't make up their mind, they want to wait till everything they think is perfect, get stuck, get stuck in their life and they never move forward and they miss opportunities. And doing my class actually is an opportunity. It's an opportunity because you get to learn from me. It's an opportunity because I'm still teaching the class. And it's an opportunity because the class is great information and it teaches you what stocks to trade each day and what direction that gap. So don't miss the opportunity to learn from me. I'm telling you, get on the right path, move forward towards your goals and dreams, whatever they may be, and don't wait. If you'd like more information, email me at melissa at thestockswish.com.