The Critical Thinking Community’s website offers a detailed in-depth description of the processes—they identify five stages—through which people can develop critical, rational, thinking. In academic-style prose, they argue that people don’t typically choose to be irrational or uncritical. They say, “We did not consciously choose to be selfish and egocentric, any more than we consciously chose to think unclearly, inaccurately, irrelevantly, superficially, narrow-mindedly, or illogically. Nevertheless, we often think and behave egocentrically. We often think unclearly, inaccurately, irrelevantly, superficially, narrow-mindedly, and illogically.” Worth a read, if you are interested in the thinking about critical thinking.