While it's endlessly amusing to consider abstractions, the fact is that our behaviors, emotions, and extremely limited reasoning capacity are all the products of evolution. We must therefore consider the constraints in order for any grand scheme to be of interest; alas, philosophers appear almost entirely ignorant of even the most rudimentary understanding of evolution's implications. What use is a castle in the air (no matter how elegantly constructed) when on the ground we ignorant little apes continue to squabble over the same old things because we're hardwired to do so?