In philosophy, incorrigibility is a property of a philosophical proposition, which implies that it is necessarily true simply by virtue of being believed. A common example of such a proposition is René Descartes' "cogito ergo sum" ("I think, therefore I am").

Johnathan Harrison has argued[1] that "incorrigible" may be the wrong term, since it seems to imply (by the dictionary definition)[2] a sense that the beliefs cannot be changed, which isn't actually true. In Harrison's view, the incorrigibility of a proposition actually implies something about the nature of believing—for example, that one must exist in order to believe—rather than the nature of the proposition itself.

For illustration, consider Descartes': I think, therefore I exist -
Stated in incorrigible form, this could be: "That I believe that I exist implies that my belief is true". Harrison argues that a belief being true is really only incidental to the matter, that really what the cogito proves is that belief implies existence. One could equally well say, "That I believe God exists implies that I exist." or "That I believe I do not exist implies that my belief is false."—and these would have the same essential meaning as the cogito.

Charles Raff[3] draws a distinction between three types of incorrigibility:

  • Type-1: It is logically necessary that, when the statement is sincerely made, it is true.
  • Type-2: It is necessary that when the statement is believed to be true, it is true.
  • Type-3: It is necessary that when the statement is true, it is believed to be true.

Type-2 and type-3 incorrigibility are logical converses, and therefore logically independent. Charles Raff argues that introspection is not type-1 incorrigible, but is in fact type-2 and type-3 incorrigible.

In law, incorrigibility laws were formerly used against minors to commit them for longer periods of confinement for status offenses, similar to in re Gault's case in the 1960s, than an adult would have been for committing the same crimes.


  1. ^ "The incorrigibility of the cogito", Johnathan Harrison, Mind: New Series, Vol. 93, No. XCIII, 1984.
  2. ^ The Free Dictionary
  3. ^ "Introspection and Incorrigibility", Charles Raff, Philosophy and Phenomenological Research, Vol.27, No. 1, 1966.