I'm twenty and I feel like I missed the space conquest spirit completely. When I think about the scientific interests that appeal to my generation, I think that advances in health, computing, and sustainable energy seem far more important. I believe that we haven't really lost our need for conquest it's just moved into domain closer to home. The question now is, how can we improve life on earth? How can we extend life? How can we collect and analyze data in better ways than before?

I think that the decline of violence in the world may have something to do with this. Since there is less violence between nation states, there is less of an incentive for countries to show their dominance on an international level. This is just a guess though.

I think that since you already know your basic criteria, it doesn't really matter which specific school you choose. The reality is that you're probably going to get a pretty much equivalent education wherever you go. I'd consider prestige to some extent. Not because this will mean a better education, but because prestigious school often attract better students, and if you get in this will help you with building solid connections.

I think this is one of those things that isn't really worth stressing about. Just look at the list of twenty or so that you have now, and just apply to the five or six that you intuitively feel best about. Also, it might be worth applying early decision. That would mean you only need to apply to one school which could make it easier on you.

This is just a hypothesis, but I think that the variance in the education that undergraduates get is more determined by the specific undergraduate than by the school. In other words, if your motivated and want to do well, you will probably do well just about anywhere.

A potential boundary is that between the seemingly objective and subjective. At the moment, science seems to be set on measuring things outside of the self. There is relatively little exploration of what one subjectively perceives. This facet of existence is almost completely ignored, even in psychology. I think in time this boundary will have to dissolve. There really is no good way of separating the outside world from the inside world.

Another one could be the artificial boundary between nature and nurture. It seems like the expression of all genes is mediated to some extend by the environment, therefore it is senseless to talk about any boundary between the two. I recently heard a metaphor that the debate between nature and nurture is akin to debating whether length of width is a better determinant of the area of a rectangle.