out of combat duty isn't really crazy". Hence, pilots who request a mental fitness evaluation are sane, and therefore must fly in combat. At the same time, if an evaluation is not requested by the pilot, he will never receive one and thus can never be found insane, meaning he must also fly in combat. Therefore, Catch-22 ensures that no pilot can ever be grounded for being insane even if he is. A logical formulation of this situation is: The philosopher Laurence Goldstein argues that the "airman's dilemma" is logically not even a condition that is true under no circumstances; it is a "vacuous biconditional" that is ultimately meaningless. Goldstein writes: See also Begging the question Circular reasoning Cornelian dilemma Deadlock Double bind False dilemma Feedback loop Hobson's choice – taking what is offered or taking nothing Ironic process theory Kobayashi Maru – a choice presented in Star Trek "The Lady, or the Tiger?" – a no-win situation List of paradoxes Morton's fork Mu Ninety–ninety rule No-win situation Pyrrhic victory Self-reference Social trap Strange loop Vicious circle Wicked problem Zugzwang References Catch-22 1961 neologisms Dilemmas Foundationalism History of logic Justification (epistemology) Logic Logical paradoxes Metaphors referring to war and violence Metaphors