Lexitechnia

Cicero, De Fato, 12.28-29, showing once again that ‘nihil tam absurde dici potest quod non dicatur ab aliquo philosophorum’:

Sic enim interrogant: “Si fatum tibi est ex hoc morbo convalescere, sive tu medicum adhibueris sive non adhibueris, convalesces; item, si fatum tibi est ex hoc morbo non convalescere, sive tu medicum adhibueris sive non adhibueris, non convalesces; et alterutrum fatum est; medicum ergo adhibere nihil attinet.”

So their argument goes: “If you are destined to recover from this illness, whether you were to call in a doctor or not, you would recover; furthermore, if you are destined not to recover from this illness, whether you were to call in a doctor or not, you would not recover—and either one or the other is destined to happen; therefore it doesn’t matter if you call in a doctor.”

This little paradox, which Cicero says was called the ἀργὸς λόγος (“lazy argument“) was sometimes used by the Stoics. In some forms this kind of argument can be compelling; but the counterexamples illustrate how this line of thought does not always hold:

At si ita fatum est: “Nascetur Å’dipus Laio”, non poterit dici: “sive fuerit Laius cum muliere sive non fuerit”; copulata enim res est et confatalis. Sic enim appellat, quia ita fatum sit et concubiturum cum uxore Laium et ex ea Å’dipum procreaturum, ut, si esset dictum: ‘Luctabitur Olympiis Milo’ et referret aliquis: ‘Ergo, sive habuerit adversarium sive non habuerit, luctabitur’, erraret; est enim copulatum ‘luctabitur’, quia sine adversario nulla luctatio est.

But if it is predestined that Oedipus is to be born to Laius, it can’t be said: “whether Laius had been with a woman or whether he hadn’t”. That matter is connected to it, and “co-predestined”, as [Chrysippus] calls it, because it is predestined both that Laius will sleep with his wife and that Oedipus is to be born from her, just as, if it were to be said: “Milo will wrestle at the Olympics” and someone answered “So, whether he has an opponent or whether he doesn’t, he will wrestle”, he would be wrong—”wrestling” is a connected action, because without an opponent there is no wrestling.

Aristotle’s Sea-Battle is a similar scenario to the ἀργὸς λόγος, where our ability to assert that an outcome must either happen or not happen also leads to paradoxical results.