An idea is irrationally false when it cannot currently be validated empirically or rationally. It may contradict evidence. It may break logic. It may depend on unverified empirical claims. Or it may belong to a speculative framework that has not earned rational or empirical status.
There are levels here. Astrology is irrationally false because it has been tested and failed. A unicorn is different. We have no good evidence unicorns exist, but we also cannot search every corner of existence with final certainty. So in a logical setting, the claim “unicorns exist” is irrationally false until evidence appears.
This matters because TST does not use irrationally false as an insult. It is a classification. It tells us how strongly we should hold an idea. Fiction, mythology, speculation, and spirituality can still have meaning, beauty, and personal value. But they should not be confused with rational or empirical truth.
In TST, irrationally false ideas can still play a role. They can spark curiosity, inspire art, open questions, and sometimes point toward future discoveries. But until they gain rational structure or empirical support, they remain outside known truth.
