Brains are hedonmic maximisers. They're only about 2% of human body mass, though. There are plenty of other optimisation processes to consider as well - machines, corporation, stock markets also maximise. The picture of civilization as a bunch of human brains is deeply mistaken.

All those things are controlled by brains. They execute the brains' commands, which is optimizing the world for fun. They are extensions of the human brains. Now, they might increase entropy or something as a side effect, but everything they do they do because a brain commanded it.

Hedonism is a means to an end. Pleasure is there for a reason.

Life doesn't give us reason and purpose. We give life reason and purpose. Speculating on what sort of metaphorical "purposes" life and nature might have might be a fun intellectual exercise, but ultimately it's just a game. Our purposes come from the desires of our brains, not from some mindless abstract trend. Your tendency to think otherwise is the major intellectual error that keeps you from grokking Eliezer's arguments.

The reason is that it helps organisms reproduce, and organisms reproduce - ultimately - because that's the best way to maximise entropy - according to the deep principle of the MEP.

Here's a question for you: Suppose some super-advanced aliens show up that offer to detonate a star for you. That will generate huge amounts of entropy, far more than you ever could by yourself. All you have to do in return is torture some children to death for the aliens' amusement. They'll make sure the police and your friends never find out you did it.

Would you torture those children? No, of course you wouldn't. Because you care about being moral and doing good and don't give a crap about entropy. You just think you do because you have a tendency to confuse real human goals with metaphorical, fake "goals" that abstract natural trends have.

Think you can more accurately characterise nature's maximand?

Why would I need to do that? My main point is that human civilization doesn't and shouldn't give a crap about nature's worthless maximand. When you post comments on Less Wrong a lot of time you seem to act like maximizing IGF and entropy are good things that organisms ought to do. You get upset at Eliezer for suggesting we should do something better with our lives. This is because you're deeply mistaken about the nature of goodness, progress, and values.

But just for fun, I'll take up your challenge. Nature doesn't have a maximand. It isn't sentient. And even if Nature was sentient and did have a maximand, the proper response for the human race would be to ignore Nature and obey their own desires instead of its stupid, evil commands.

That being said, even you instead asked me to answer the more reasonable question "What trends in evolution sort of vaguely resemble the maximand of an intelligent creature?" I still wouldn't say entropy maximization. The idea that evolution tends to do that is an illusion created by the Second Law of Thermodynamics. Because of the way that 2LTD works, doing anything for any reason tends to increase entropy. So obviously if an evolved organism does anything at all, it will end up increasing entropy. This creates an illusion that organisms are trying to maximize entropy. Carl Shulman is right, calling entropy nature's maximand is absurd, you might as well say "being attracted by gravity" or "being made of matter" are what nature commands.

A better (metaphorical) maximand might actually be local entropy minimization. It's obviously impossible to minimize total entropy, but life has a tendency to decrease the entropy in its local area. Life tends to use energy to remove entropy from its local area by building complex cellular structures. It's sort of an entropy pump, if you will. So if we metaphorically pretended it evolution had a purpose, it would actually be the reverse of what you claim.

But again, that's not my main point. My main point is that while you have a lot of good sources for your biology references, you don't have nearly as good a grasp of basic psychology and philosophy. This causes you to make huge errors when discussing what good, positive ways for life to develop in the future are.