Reading Sagan, the great popularizer

I decided that it’s time to get my Sagan on. Which is to say, having finished the tome that is GEB, I am taking a break from Hofstadter for a bit and reading a book by Carl Sagan: The Dragons of Eden, published in 1977. It’s about the evolution of human intelligence, and I’ve gotten almost as far as the evolution of human brains. I’m maybe 1/3 of the way through. Here’s my recap so far:

– Human history is crazy short, and the Trojan war was like seven seconds ago. (Sort of.)
– DNA is pretty impressive, but now we store way more information in “extragenetic” systems like brains (and books), and they’re the only things that’ll keep us going.
– We’re pretty sure that memories and other information are localized (stored in relatively specific places) in the brain, but we keep extra copies around in case one stops working.
– We’re smarter ’cause we have a higher brain-mass-to-body-mass ratio. Incidentally, dinosaurs were probably pretty stupid.
– There are a crazy lot of possible brain states.
– We can talk about the brain in three sections: the reptilian complex is the oldest and has to do with aggressiveness, ritual, and hierarchies; the mid-brain (limbic system) is maybe half as old and has to do with emotions, smells, religious feelings, and some other stuff; and the neocortex is the newest part and does a lot of sophisticated stuff like planning and language.
– …Also there was something about the Phaedrus and a chariot.

Of course, Sagan goes into a lot more detail about what each part of the brain does, among other things, and he gives examples like soldiers with particular injuries who lost very specific abilities due to the part of the brain injured, and gives some useful charts and diagrams. He also mentions that dolphins have the second-highest brain-to-body mass ratio, and sharks are the smartest fish.

I like it so far, but I should read Sagan in his fortĂ©. Maybe when I finish Dragons, I’ll go watch “Cosmos” on Hulu.


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