So irrationalism seems to be an obvious sz.com forum topic as sz is an irrational state to be in, but there may be some less obvious points to consider. Rational can be considered synonymous with reasonable although there are differences as rational, for one thing, alludes to rules whereas reason does not, unless maybe the formal rules of logic. A typical situation where someone might say someone is being irrational is in an argument where any appeal to truth, morality, logic, fairness, compassion etc. is being ignored. In my simplistic way of thinking this ties nihilism into the irrational area of thought as someone who cannot be swayed by these things nihilistically dismisses them as nothing.
Nihilism was a major component of my thinking over the years, where the critical destruction of commonly held values was an idle practice of mine. Things like marriage, and going to graduations, or celebrating birthdays, or going out on new years eve and important life events and things like that were nihilistically nullified by criticisms of mass behavior. This is just to make a concrete example, as nihilistic beliefs often result in doing nothing rather than doing something. I think the anatomy of this nihilism is social withdrawal, odd thoughts, angst (anxiety), and rejection by others and others by self.
So this nihilism was a major feature of my thinking over the years, but not only nihilism is irrational. It is also irrational to be absurdist, thinking that there is no meaning to existence. Also it is irrational to focus on the ironical, that which does not follow from what one may reasonably expect. After all, if one’s expectation is not reasonable isn’t it ironic that it happened that way at all? Also most people can relate to the irrationality of being in an emotional state, especially in personal relationships. And then there are irrational ways of thinking such as jocular, in riddles, intuition, nonsense, imagination, divination, intoxicated, delusional, paranoid etc.
All of these things are very interesting but again to keep this short I’ll again mention the F-word, Foucault, and his argument that psychiatric treatment is based on social order and control. Of course rationalism and rationality, whether that found in science, or in normative social thought depends on people thinking in a corresponding way. MIs such as sz are an organic cause of thought disorder which automatically offends the rational order of society. Sz wouldn’t start a revolution as it has been depicted doing in fiction, but the nature of reality is sort of argumentative in nature, so in a condition like sz where there is an organic cause of irrationality (and possible argument) the solution is both rational in that it is scientific, and rules based. So as a threat to rationality it is neutralized.