PM5318: On Moore's paradox

In philosophy, Moore's paradox refers to statements of the form:

I believe it but it isn't true

It is named for G. E. Moore, who was the first in the philosophical literature to note the absurdity of these statements.

Moore's paradox is asserting that something is true, yet that at the same time one does not believe it; or believing that something is true, yet at the same time one does not believe that one believes it.

Moorean sentences have three essential components:

  • they are in the first person: I believe X but X is false is paradoxical, but you believe X but X is false (second person) and she believes X but X is false (third person) are not.
  • they are in the present tense: I believed X but it is false is clearly not paradoxical
  • they are about specific beliefs, rather than one's beliefs in general: Something I believe is false does not seem so paradoxical, but rather an honest acknowledgement of one's own inevitable fallibility, since it is almost certain that many things one believes are false. It is only when one moves from the general to This particular thing I believe is false that the paradox occurs. (Although, see the preface paradox for an argument that the general claim is also paradoxical)

Philosophers distinguish two versions of Moore's paradox, the omissive and the comissive:

  • omissive: X is true but I don't believe X is true
  • comissive: X is true but I believe X is false

In the first case, one lacks belief in something which one acknowledges to be true, but one doesn't disbelieve in it either (neither believing nor disbelieving.) In the second case, one is saying that something is true, but that one actively disbelieves in it (believes it to be false).

In Maratreanism

Maratrean logic accepts that Moore's paradox is indeed paradoxical. This is a basic principle of rationality. It connects logic to personhood (the first person is special) and to time (the present is special). The I, the Here, the Now - these are far more than mere indexicals.

To which let us add the addendum: I ought to believe X, therefore X. This is a principle of inference. It is similar to the principle of inference which Moore's paradox exposes: I believe X, therefore X.