Cosmological Jeopardy: I'll answer your answers with questions... Why is it that something--or even just a multitude of strings of overlapping different things--needs always to have existed? Is it that it makes no sense to speak of existence if there are not particular things that do so? And even if we accept this claim, and that the existence of something(s)without a cause is the way to honor it, why does this thing (or things) need to be God and not the universe itself? Is the universe not particular enough?

To be plausible, all of your claims about imagination need to be qualified as "other things being equal", since there are, of course, examples of vivid imagination leading to terrible (and destructive and intolerant) actions. This said, I'm inclined to agree to most of the general claims you make for imagination. And in fact, we've just embarked our daughter on a Waldorf education that emphasizes the development of imagination, and all the benefits that this supposedly brings. However, to really assess all of this, we'd need a somewhat detailed account of what exactly counts as imagination (and greater or lesser amounts of it), and some tests to determine whether it links up in positive ways with the other properties you've identified. This task is partly philosophical, but mostly, I think, a matter for empirical psychology. It's an interesting topic, though. Sorry I don't have more to add.

If two wrongs don't make a right, try a third. I think Nixon said that. But he wasn't the most reliable ethicist, and I can't think of a sitauation in which two wrongs would make a right. A just punishment might seem to come close, but doesn't really: the score may be settled when you've served your time, but your original crime isn't thereby made right (even though it's forgiven); and the sentence you served wasn't a second wrong anyway.

Philosophy might help in sifting through the possible reasons for conserving biodiversity--not just diversity of species, but also of types of ecosystems and also, perhaps, of genetic diversity within a species. And what is worrying about our current situation, by the way, is not simply that species are going extinct (this has always happened), but that diversity is disappearing at an alarming rate and on an alarming scale--one that is perhaps comparable to the five or so mass extinctions that have taken place over the past 440 million years. And we seem to be causing it! There are surely a number of very good instrumental reasons for preserving biodiversity. First, in biodiversity lies a treasure chest of potential medicines, foods, and other things that might be useful to us. Second, we don't want to lose clues to a more complete understanding of the workings and history of the Earth. Third, for many of us, even non-religious types, the diversity of life is a deep and awesome source of aesthetic and...

This is a good but difficult question. The answer, I think, depends upon what you mean by a "self". (Many people, including those who believe in immaterial, unified, and potentially disembodied "souls" would not agree that the notion of a "self" is open to several different, but equally useful characterizations.) If we require for the existence of a "self" the type of cognitive integration and global powers of rational understanding and planning that sadly break down in such patients, then, when the break down has gone too far, there remains no self in this sense. Nevertheless, there remains, of course, a body with all sorts of sophisticated abilities (to walk, to speak, etc.); and for all that I've said, there may remain a soul.

Even in a world without laws or social rules, our ability to do exactly as we please would, presumably, be constrained by by all sorts of things--our own abilities, the actions of other people, gravity. (This won't be true, of course, if we could somehow adjust our desires so that we didn't want anything that we were constrained from having. But if we can do this, we might as easily do this in the world with laws.) In fact, the existence of rules and laws seems actually to allow us to do more of what we want. For example, the enforced convention that we drive on the right side of the road (in the US) allows us more efficiently and effectively to move about and do many of the things we want to do, even if it prohibits us from driving however we like with legal impunity. So, I doubt that anarchy would give us the "true freedom" you seek. But I wonder how much value we really place on "freedom" in this sense.

I have to say that from your description of the debate I'm inclined to side with your friend. His world contains a lot less suffering, and lot more human flourishing. You talk about a "healthy balance" of well-being and suffering. But why is this better than a world with very little or no suffering? Perhaps your idea is that some suffering is somehow needed in order to maximize human well-being. Is it that there needs to be some suffering so we can realize the well-being that comes from struggling towards and eventually achieveing something? Or is it that a world in which everything went perfectly would contain no background of even mild misfortune against which to appreciate our well-being as well-being. Such a world would be experienced as "flat", and almost dull in it's unwavering fortune. I'm skeptical of this, but in any case, the "healthy balance" of misfortune that might allow us to realize these greater forms of well-being would seem to require a lot less suffering than does our actual world. ...

Although "mental content" is a term of art, and used in different ways by different philosophers, most take it to be the way--the proposition or information--that a mental state represents the world as being. My belief that Bush is president and my belief that Alaska is large differ in mental content--the first represents the world as containing a guy named "Bush" who is president, the second a large state called "Alaska". By contrast, my belief that it's sunny outside and my desire that it be sunny outside share the same mental content, though they constitute different attitudes towards this content. Even if this notion of mental content is clear enough, there are a number of important and unsettled issues surrounding it. One prominent issue is whether (and if so exactly how) the contents of our mental states are determined by features beyond the surface of our skin--most notably our environment and socio-linguistic setting. See http://www.amherst.edu/askphilosophers/question/13 for more on this....

It's not clear that you can go back in time and kill your former self: a former self that doesn't get killed seems required for your presense at his side, contemplating the crime. This is a version of the grandfather paradox (you can travel back and talk to your own grandfather, but not kill him); though I should say that there are some (not me!) who hold that this type of thing is in fact made possible by a multi-verse interpretation of quantum mechanics. On the other hand, I don't see any impediments to using time-travel to kill off the final stage of yourself. (This needn't be in the relative chronological future if your life ends on a time-traveling adventure.) Whether it's suicide of merely murder seems purely terminological. It's "suicide" in one sense (you're done in by one of your own temporal stages), but not another (your final stage doesn't do itself in).

Eternal Sunshine of the Spotless Mind is an amusing (or so I thought) movie about exactly this.