An irrational pragmatist embraces relativism. They lets usefulness do too much work. This person tends to treat comfort and identity as enough reason to hold an idea as true. Irrational Pragmatism begins when the human need for meaning, comfort, or identity outruns the discipline of truth. Pragmatists tend to focus on tribal belonging, emotional benefit, or magical thinking. More deeply, they do not fully accept public truth as the shared basis for truth. They are overly skeptical of science, law, and journalism. To the irrational pragmatist, any that works psychologically or socially is embraced as true. To them, usefulness is all that is needed for a belief to survive.
On a per topic basis, like astrology, the irrational pragmatist may say, “It works for me,” and treat that usefulness as validation. If astrology gives comfort, identity, or a way to interpret relationships, that becomes enough. With Valhalla, the same pattern can appear: a mythic afterlife may inspire courage or loyalty, and the irrational pragmatist may slide from “this story is meaningful” into “this story is true.” Meaning becomes mistaken for truth.
String Theory shows a subtler version. The irrational pragmatist view of string theory might give too much weight to the elegant math or that it feels like proven science. But in TST, elegance is not proof. A useful or beautiful framework still has to answer to reality.