Hello, good time of day.
My name is Victor, I'm 19. I'm a student of computer science from Russia (so my English is far from perfect, and probably there will be lack of articles; please excuse me).
There wasn't any bright line between rationalist!Victor and ordinary!Victor. If I remember correctly, five years ago I was interested in paranormal phenomena like UFO, parallel worlds or the Bermuda Triangle (I'm not sure I truly believed in it, probably I just had fun thinking about it: but I might have confessed the cached thought about scientists not knowing important things about the world) and liked reading the pop-science books at the same time. Then I realized that there is a beauty, honesty and courage in the scientific worldview and shortly thereafter, I became a person from the Light Side: not because science was true, but because it was fun.
But at least I rejected the Bermuda Triangle. I was too honest to leave inconsistencies in my pool of beliefs; so long, pseudoscience!
Maybe at the same time I discovered the concept of the utility function and blog of a psychologist arguing that there is nothing wrong with an egoism. Something clicked in my mind; the explanation of human behaviour was beautiful in it's simplicity, and there were some interesting implications of this explanation. Then Dawkins and realization that evolution is just a natural continuation of the laws governing non-organic matter. Evolution was fun, and also it was true. I became an Guardian Of The Evolution, and I was fighting superstitions. It was point of no return: it was impossible to defend telepathy again (why there aren't any telepathic wolves?).
There was moment of marvel, when I realized that there wasn't any reason to expect any intellectual feats from a naked ape living in town; our brain wasn't adapted to the current environment, but it is still working, and it is working much better than you should reasonably expect. Intelligence is fragile, and humanity is the underdog I should root for. At that time, I had already known about cognitive biases, but my feelings towards this topic became different after this insight.
I don't remember when I started reading LW. I might have learned about utility functions here, but I'm not sure. LW was changing me gradually. In the course of two or three years I have been noticing some small changes: I started admiring the scientific method, I understood the power of the intelligence, sometimes I withdrew from an argument because there wasn't any disagreement about anticipated experience there, et cetera.
I don't know where to draw a line between "non-rational age" and "rational age". But I sure as hell I'm with you guys now.
Perhaps you'll find this funny: