What makes people irrational thinkers?

[Belacqua]

I think we can "escape" our prejudices when we employ type 2 thinking.

One thing to keep in mind is that our minds are not (as some religious people would have us believe) pure sparks of reason temporarily trapped in the dross of the body. Human beings are intrinsically, unavoidably, embodied and embedded things. It is impossible for us to escape these structures, and to a very large degree the structures determine what we can think. 

The type of body we have determines the kind of input we can take, the way we are likely to interpret the sense impressions, the scales and amounts we can deal with.

The fact that we think in language structures our concepts even as we form them. Language has metaphysical assumptions built into it -- for example, the idea that there are objects and there are actions (i.e. nouns and verbs). Verb tenses, etc. As soon as we formulate a thought, it is already limited in the form it can take. 

And of course no human is raised without culture. The culture we are raised in determines nearly all of our ideas about things. 

If we realize that some set of things we learned as children is in fact foolish, this doesn't mean that we have gained access to some pure vein of truth. It just means that we have gained some tools to evaluate thoughts from our culture, and applied them. Then when we settle on a new view of things which we think is more likely, it is not some new thing we have invented but a different set of explanations which our culture has provided us. No one is ever outside of culture. (And unfortunately, when some people change their beliefs from one set to another within their culture, it seems to be less a function of analysis than of what seems cool. Who has the cleverest propagandists.)

Foucault used the word episteme for the set of ideas and values which a given culture uses to structure its view of truth -- or of what ideas are acceptable. To range outside this strictly bounded area of thought will get you labelled as anything from mildly eccentric to criminally insane. But even the insane tend to be insane in certain recognizable ways, as a combination of bodily function and cultural expression. 

The part that some people don't like to hear is that culture is contingent. And the episteme of any given culture is contingent on its time, place, and genealogy. We may be happy at the bottom of our well and assume that this time we have really seen the truth. But people who claim not to exist inside an episteme, or to have no ideology, or to have no metaphysical beliefs, are just telling you that they haven't examined their own beliefs. 

And while the options that our culture gives us are contingent, not some kind of pure truth, it would be irrational to reject all of these choices. If rationality is the ability to function thoughtfully in the world, then accepting our culture's episteme is unavoidable. We can ponder it, we can read texts from other times and places to get glimpses of other ways of thinking, but the very analysis we do is included inside the episteme of our time. 

Unless somebody wants to argue that the mind is a pure spark of reason with unmediated access to capital-T Truth.