what do you know that you do not know?

This question can be interpreted in at least two different ways, based on internal ambiguities. From one perspective, we can take it as a inquiry about those things we have knowledge of our own lack of knowledge about. I know that I do not know what day I will die, or what the afterlife might be like. I know that I do not know if there are aliens in outer space. I know that I do not know how to speak the Zulu language.

On the other hand, we can take the “that” as an equals sign, and the question becomes the paradoxical one, what is it that you both know and do not know (simultaneously). It is an easy temptation to dismiss questions like this out of hand, as meaningless nonsense, but as powerful thinkers from Ecclesiastes to Kierkegaard to Nils Bohr and beyond have noted, it is the most paradoxical concepts that tend to lead to the most powerful insights.

Unfortunately, in this case, no powerful insight arises for me –at least not immediately –out of contemplating this question, so for the moment, I will simply leave it with this respectfully inadequate answer.








No matter how strong an inductive argument is, it cannot guarantee results the same way a deductive argument can. It is always theoretically possible for the premises of an inductive argument to be true and the conclusion to be false.

In the case you mention, one might make a strong inductive argument to the effect that since the first 99 statements in the book were true, the last would be as well –but that conclusion might still be false. Furthermore, if you are aware of how the book was constructed and you do not include that information in your argument, you are guilty of the fallacy of suppressed evidence, and the argument can no longer be considered “strong.” Clearly, writing a false statement in a book of all true statements does not magically make that last statement true, and your knowledge of that fact must therefore be counted as a factor when judging the strength of the argument.

That may seem hopelessly subjective, but unlike the mathematically precise and assured conclusions of deductive arguments, the conclusions of inductive arguments can never be divorced from the real-world vagaries of context and circumstance.




explain how doubt leads descartes to postulate human essence as non material





whats (if anything) is wrong with epiphenomenalism?

I’ve already answered several questions on this subject, but here’s a quick summary of my view: Epiphenomenalism fails to offer an adequate alternate explanation for the phenomenon it disbelieves –i.e. the subjective experience of making choices and having our bodies respond (at least partially) to our will. In particular, it cannot explain why, given the hypothesis that no part of our bodies is actually under the conscious control of the [fictive?] will, do some parts of the body seem to be under our command, while others, like the heart, do not.

Also, how can one explain the existence of physical skills such as wiggling your ears, playing the piano or juggling? These are highly technical skills that seemingly take willpower to gain. It seems difficult to accept that they are talents our bodies (randomly?) acquire independent of any conscious effort.

A circular argument is technically a valid argument. For every case in which the premises are true, the conclusion will be true. So what makes it a bad one?


Thanks for your question. Although we tend to focus on validity in logic, it is actually only the minimal baseline requirement for a “good” argument. Valid means that the conclusion is guaranteed to be true if the premises are true. But in order for an argument to be “sound” it needs also to have true premises. Otherwise, it might just be “vacuously valid” as in the case where the premises contradict each other, and thus can never be true simultaneously.

P and not P
Therefore X

is also a “valid” argument, no matter what P and X might be. But it can never be sound.
Your case, however is different.

Therefore P

The problem with the circular argument is not that it cannot be sound, but that it does not play the function of an argument –to convince us of things we did not believe before. A circular argument yields exactly and only what you put into it. It does not increase your understanding or store of knowledge. It is “bad” not because it is invalid, but because it is non-functional. If presented in a debate or philosophical paper, it is considered misleading and illegitimate because it claims to prove something that it presents as a given or as an assumption.