I feel your pain: I seem to lose any philosophical knowledge or acumen I might have had when I'm "out of the game" for more than a week. I'm inclined to think this is because the human mind (or at least the normal human mind) wasn't evolved to engage abstract issues and subtle dialectic with the duration and intensity required for philosophical investigation of any lasting quality. (My memory is particularly ill-suited--I remember philosphers' names much more readily than their doctrines.) Philosophical thinking seems a by-product of more evolutionarily pressing cognitive skills like causal reasoning, hypothesis formation, folk-psychological explanation, decision making, negotiation, and so on. And unlike, say, musical ability, philosophical ability seems, alas, only to be a disadvantage in sexual selection. I find that re-reading things that particularly engaged me in the past (even my own writing) can get me back into philosophy, and remind me that I've retained a lot more ability, knowledge, and...

That's a great example, and a great question. There are a number of obstacles to conveying the taste of an avocado to another person in words. Some are practical and some are philosophical. First, even those of us who've tasted avocados will have difficulties recalling the taste when we're not actually tasting it. I bet I could do pretty well distinguishing avacados from other substances in a blind taste-test, but my current acquaintance with the taste is not so determinate right now as I sit in my office trying to conjure it up while drinking water. I would have an easier time describing the taste to your friend if I were currently eating an avocado. Second, we seem to have no "purely qualitative" language for picking out the way things taste to us "from the inside". By this I mean that all the descriptions we might use seem to make inelimanable reference to some external substance, and then draw comparisons with the taste it typically causes. Even "salty" means something like "tastes similar to...

I think this is possible, particularly if one or both people have done something to seriously damage the relationship, or if one person is simply impossible to live with. It might be better for all concerned for a relationship to end even if the one who ends it is still in love. I suspect, however, that your question concerns cases in which no particular wrong has been done, and the relationship is perfectly workable. Can someone remain in love and still end a relationship simply in order to pursue other opportunities (romantic, professional or otherwise)? This might seem impossible if you have a conception of love as completely unconditional and exclusive. (If you also regard love as eternal and unchanging then it's difficult to see how, as you ask, one can genuinely love at one time and not at another.) But I don't see why a state that doesn't fully satisfy these conditions shouldn't count as love. We certainly talk of people falling in and out of love, of being in love with more than one person, and...

Illusions are "real" in one sense and not in another. Unreal: The railroad lines look to me as if they meet in the distance, but they don't. In this case, reality isn't as it appears to me. Real: I am part of reality, and so are my mental states. One of those is that the railroad tracks (falsely) appear to me to meet in the distance. This is a robust illusion that I and many others are really subject to.

When it comes to the justification of many of our beliefs--particularly those about the way the world works, and the way it is beyond our immediate environment--I don't think we are in a qualitatively different position now than we were 500, 5,000 or even 50,000 years ago. It's plausible to think that homo sapiens of that vintage shared our lingiuistic ability; and if so, this presumably helped them rely upon the testimony of others in their band (who in turn often stood at the end of long chains of such testimony) to form beliefs about the state of things across the mountains, or in the generations before they were born, or in their causal connections (e.g., how you start a fire), or in their cosmic ordering. As you point out, we too rely--and can't really help but rely--upon the claims other people make about the way the world is and works. Of course, there are differences in degree. We have available to us many, many more sources of testimony (along with many more sources of quasi-observational...

We might hold that the moral status of a given action-type depends upon the circumstances in which it occurs. So, knocking your opponent over might be entirely permissible on the football field, but not in a presidential debate. Some have held that lying is permissible in some circumstances (the "white lie") but not in others. This doctrine is "relativistic" in the sense that the status of an action-type is held to be "relative to" the different circumstances in which it occurs. But this is not the sense people have in mind when they talk of moral relativism . That view generally allows that the moral status of a particular, datable action-token (or an action-type in which all morally relevant contingent circumstances are specified) might depend upon the views of the individual evaluating that action, or upon the contingent norms of her culture. (Moral relativism takes a variety of forms.) As a moral relativist, I might say that infidelity--even a particular act of infidelity--is wrong for me, but...

Suppose we know through logic alone that something is true about the world. I don't know if there are such truths (or even such ways of knowing), but a good candidate might be the claim that no state of affairs simultaneously holds and doesn't hold of the same portion of the world. If considerations of pure logic (assuming there is such a thing) show us that this is really true of the world then they also seem to show that it is true of any possible world--any way that the world might have been. Changing the world's details, and even its physical and metaphysical laws wouldn't seem to affect the status or applicability of logic itself, or of any truths that might follow from it. That seems like a reasonable inference, but I haven't, alas, read Yourgrau's book, and so can't apply it to the existence of time. But maybe someone else can...

Discovered things seem to exist independently of their discovery (think of uninhabited islands and rare species), while invented things come into existence in the very process of their invention (think of the first light bulb). But even if the first light bulb came into existence when Edison invented it, what about the idea of the light bulb? Did he invent this at the same time, or was it, as you suggest, hanging around for eons just waiting for Edison or some other genius to stumble upon it? It's a great question--and connected at root to venerable metaphysical questions to which, in my view, we still lack satisfactory answers. The issue isn't so much about how we use the concepts of invention and discovery (though this is interesting), but rather about the unsettled status of the "ideas" that we discover/invent. On the one hand, we certainly seem to talk of ideas as things that transcend particular, spatio-temporally located acts of thinking in which they might figure. We might say: George...

That's right. A is a necessary condition for B: B obtains only if A obtains. A is a sufficient condition for B: If A obtains then B obtains. A can be a necessary but not a sufficient conditiion for B. Example: having legs is a necessary but not a sufficient condition for walking (the legs also need to be used in a certain way). And A can be a sufficient but not a neceesary conditon for B. Example: dropping a ball is a sufficient but not a necessary condition for moving it (the ball could also be moved by by throwing it upwards). This is perhaps the most common way of defining these expressions. And I think it reasonably captures our fairly straight-forward and unproblematic usage. But as always, things are more complicated when you scratch beneath the surface. To do so, look at the entry on necessary and sufficient conditions in the Stanford Encyclopedia of Philosophy.

A full answer, I suspect, is evolutionary and not merely cultural. Sex is pretty universally a more private activity than, say, eating. (I'm not the one to tell you why this is so, but I gather that it is.) By contrast, it's hard to see how hunting and warfare, which are obvious sources of our attitudes towards violence, could or would be carried out in much privacy. And it's not surprising that our culture (or any culture) might be more squeamish about publicizing private acts than public ones. But even if this does explain the greater censorship of sex than violence, it's not clear (as the statement of your question implies) that this should be so.