To break up the awkward silence at the start of a recent Overcoming Bias meetup, I asked everyone present to tell their rationalist origin story - a key event or fact that played a role in their first beginning to aspire to rationality. This worked surprisingly well (and I would recommend it for future meetups).
I think I've already told enough of my own origin story on Overcoming Bias: how I was digging in my parents' yard as a kid and found a tarnished silver amulet inscribed with Bayes's Theorem, and how I wore it to bed that night and dreamed of a woman in white, holding an ancient leather-bound book called Judgment Under Uncertainty: Heuristics and Biases (eds. D. Kahneman, P. Slovic, and A. Tversky, 1982)... but there's no need to go into that again.
So, seriously... how did you originally go down that road?
Added: For some odd reason, many of the commenters here seem to have had a single experience in common - namely, at some point, encountering Overcoming Bias... But I'm especially interested in what it takes to get the transition started - crossing the first divide. This would be very valuable knowledge if it can be generalized. If that did happen at OB, please try to specify what was the crucial "Aha!" insight (down to the specific post if possible).
I never had a watershed moment when I ‘discovered' rationalism. For those of you who grew up with religion and take faith as a more or less given part of society, I must have had a rather peculiar childhood; When I was little, I spent quite a lot of time with my grandfather who was an uneducated farmer and had never heard of Bayes’ Theorem. (But loved it when I recently explained the basics to him.) I remember starting sentences with "I believe…" and I never got any further before being interrupted with "If you want to believe, you can go to church. Around here we go with the evidence”. Upon being asked about the possibility of an afterlife, he went: “If there is an afterlife, it can not be observed, and if it can not be observed it is certainly not important enough to talk about”. He is a rather abrupt old man. Another nugget of wisdom was “There is an infinite supply of possible mistakes to choose from, so there is no point in making the same one twice.”
I also live in a country where about 80% of the population are Atheists/Agnostics, which makes religion something the crazies are talking about. Empiricism and rationalism has simply been the default position for my entire life, even if not expressed explicitly or in mathematical terms.
Even atheists who are taught from the age of five that ‘belief’ is not a permissible word are not exempt from biases of course, and the first time I consciously noticed that particular problem was right after I died (which could count as a watershed moment.) In my early twenties, I went through a bit of a mental/emotional crisis (for reasons that I may end up covering in another post) that I handled through extreme amounts of exercise and caused me to lose weight. During my yearly checkup at the doctors, he noticed that I was severely underweight. (we’re talking a BMI of about 12 here, so severely is not an understatement) He spent quite some time going over my eating habits and couldn’t find anything wrong. Two months later, I was found dead by the roadside and revived in the ambulance. Random passersby who know CPR is a good thing (TM). My body had simply shut down due to spending more energy than I had absorbed over an extended period of time. After recovering for a bit at the hospital, I slowly realised that the doctor had observed something wrong (a very low BMI) and upon finding that the normal explanation (anorexia) didn’t apply, he had discarded the observation rather than looking for other possible explanations. I was quite upset about this, and I also started examining myself with respect to why I hadn’t noticed that something was wrong either.
This experience made me rather obsessed with cognitive science and nutrition / exercise (which may be worth another post, this community seems interested in the topic); enough to take a year of pre-med, a year of psychology (which didn’t help much) and to read all I could find about cognitive theory (which did, especially Gödel, Escher, Bach which is also a wonderful book when considered only on it’s merits as literature.) This was in 1994, so quite a time before OvercomingBias and LessWrong, or I would most certainly have found this place back then. (btw, we have free tuition here, so I take at least one college course per semester, hence the odd academic choices. This year I’m doing introduction to quantum mechanics which led me to stumble upon the quantum physics sequence which led me to read HPMOR, which made me lurk around this site for the last five months and reading the rest of the sequences before creating an account.) (this comment counts both as a 'hello' post and a 'Origin story' post :)