An article about defiance to crash test (or test) anything.
What is a rationalist?
Well, right away you've gone about asking the wrong question in the wrong way. Which is itself sort of what rationality is about.
Rationality is the art of thinking. You know how anyone can pick up a pencil and scibble, but it takes skill and practice to draw or write? That there are techniques you can use to refine your natural ability to draw or write? Well, thinking works the same way. There are techniques you can use to think better, that is, be better able to get the right answers from the same information. A rationalist is therefore a lot like an artist or a writer; somebody who is really good at thinking in the right way. Like art or writing, this doesn't happen overnight.
Rationality is an art in that is must be refined by it's users, but it is also a science. The brain, and the things the brain interact with (ie reality) are shaped by concrete facts and determining these facts are key to being a better rationalist. Therefore, a rationalist must also, to a degree, be a scientist; one ready to accept and refine scientific knowledge and to use the scientific method to further their own abilities.
The most important thing about being a rationalist is learning how to think; establishing the patterns consistant in natural or socially ingrained throught (biases), then overcoming these biases when they interfer with your ability to determine facts. It might help to think of everyone as being crazy; it's not far from the truth, as people's biases act like mental blocks that can prevent them from seeing truth right in front of their face.
TL;DR Version : Rationality is Learning to Be Sane