I am beginning to think that reading all of these books in a row is going to set up a huge compare/contrast chart in my head where I will attempt to unify everything I've read this semester. But it's not my fault: so far, all three of the four Masters of Suspicion have collided (particularly on the subjects of the nature of man, man's instinct, and the ordering of the universe). I'm just trying to pick up the pieces.
Right now, I can't stop thinking about how differently Nietzsche's concept of instinct is from what Darwin outlines in Origin of Species. Nietzsche very strongly believes that man was like all other animals once, which seems to line up with Darwin's theory of macroevolution. However, Nietzsche believes that integral to this animal-state, man relied much more strongly on basic instincts. Nietzsche highlights the shift animals take from base instinct to relying on reason by beginning with the creatures that once lived entirely in water. As the environment changed around them, remaining in the water was no longer a viable way to survive. This means that the organisms either simply died because their instinct's instructions weren't enough to keep them alive any more, or they somehow used reason to figure out how to survive on land. This reduction from relying on infallible instinct to the incredibly weak faculty of reason is what began the animal kingdom on the journey to "de-evolving" into humans with well-formed reasoning capacities. I call this a de-evolution because while it highlights the same changes that Darwin points out through macroevolution, Nietzsche is adding an evaluative statement to this change: it's bad. Because animals had to develop their ability to reason (which Nietzsche compares to having to rely on "your weakest and most fallible organ"), weaker humans eventually used reason to craft morality and throw the universe into the sickness of guilt and bad conscience.
So to Darwin, evolution is a gradual movement toward perfection for all of the natural world. To Nietzsche, evolution represents the force that allowed humankind to throw off the natural ordering of the universe that existed when instincts ruled the day.
I will hopefully be able to go into detail about this later, but a lot of what Nietzsche had to say appealed to me. He writes beautifully and passionately, and his arguments are convincing. So, as far as a general reaction to the book goes, I have this to say: if I were not a Christian, I think I would be a disciple of Nietzsche. Or I would worship nature. Interestingly, I think the two would go very well together.