Is there anything to the idea that someone only really understands a concept if she can explain it to someone else? Sometimes I think that the things we know most certainly (such as that 1+1=2) are actually the most difficult to explain.

For what I've seen until now, logical laws are always assumed to be necessarily true (in the "all possible worlds" sense), but is it possible that this necessity is weaker? Is it possible that our logical capabilities are adaptations to physical regularities of the actual world and are still evolving, together with our minds? If our logical capabilities are tracking our evolution, then the Necessity of Logic laws could be only Physical, instead of Metaphysical, and there could be possible worlds where the Physics would constrain Logic differently. This (I think) would also have implications regarding the Ontological commitment of Logic: instead of assuming that there is none, it would be possible, even likely, that the physical existents of the World would appear in our logical theories. Has anyone put forward sustained arguments for/against this?

Setting aside the sort of lies told by parents to children, are there any lies which, in the panelists' view, it would benefit people in general to believe? (For instance, you might think that although there is no god, religious belief is so beneficial as to outweigh a strict concern for truth.) Or is it the case that there is no lie worth believing?

I hear people look at a woman from a distance and exclaim "She is beautiful". I did that myself before. But my experience in relationships with women leaves me with a big question. Is beauty visible? Or what makes a thing beautiful?

I've noticed that most comments on abortion ignore the question of foetal conciousness and the stage at which the foetus becomes sensitive to pain, and is susceptible to suffering in the course of the abortion procedure. The gradualist approach (the foetus has few rights in early pregnancy but more rights at later stages) is attractive but suffers from the drawback that it does not provide a definite point in gestation at which personhood can be considered to start. Would it be reasonable to think of the onset of foetal consciousness as providing such a starting point? (I know there are immense practical difficulties in identifying the onset of consciousness but I am looking at this question as a matter of principle.)

It is a well publicized fact that voters are less likely to vote for atheists than for individuals of practically any other sort of minority. Why is this sort of discrimination generally not regarded as indicative of a really significant injustice? Why isn't the difficulty of atheists to achieve political office viewed as on par with racism, homophobia or other kinds of discrimination?

Is there any knowledge/wisdom/insight that cannot be expressed as a proposition?

I've been reading philosophy for some time, and I've seen something I couldn't understand however hard I try. There've been a number of comments that some ideas are too sceptical. There've also been attempts to defend philosophers from accusation of being sceptics both by themselves and their defenders. Therefore, it seems to me that Scepticism (or being sceptical) is generally considered somehow negative. But why is it so? I simply can't see anything wrong with Scepticism. I am aware of possible cases when defended ones are mistakenly considered as sceptics, but there's possibility that those defended may indeed express sceptical views as well.

I'm thinking about relative position (left, right, up, down, ahead, behind). My general question is whether you think that these three oppositions (left/right, up/down, ahead/behind) have the same "status". For instance, for every point moving on a straight line, there is a meaningful and precise difference between ahead and behind, but not necessarily between left and right or up and down. Another example: for any (physical) object on the surface of a planet, the difference between up and down is clear, but not the remaining two oppositions. Another one: if it is settled, in a given 3D situation, what is left and right, then it is also necessarily settled what is ahead and behind, and what is up and down, but this does not (always) work the other ways around. What do you say? And do you think that the opposition between inside and outside has some relation to the other ones?

How do philosophers (or academics in general) justify their choice of profession? How is it defensible to be studying esoteric ideas with relatively few (if any) implications for the greater good, rather than devoting one's life to solving the much more practical problems that burden so much of the world's population? I realize that some philosophical ideas have had important worldwide impacts and have directly improved people's lives, but I doubt that almost any philosophers working today would say that that's what they expect to come out of their analyzing a particular view of Wittgenstein's or whatever. (I think this question ought to be asked of most professions, but it seems that philosophers would be thinking about this sort of thing much more so than would, say, investment bankers.)