and sometimes even the premisses of a conclusion, αίτίας, as, for instance, in his "Metaph." iv. 18 ; " Rhet." ii. 2 ; " De plantis," i. p. 816 (ed. Berol.), but more especially "Analyt. post." i. 2, where he calls the premisses to a conclusion simply αίτίαι τού συμπεράσματος (causes of the conclusion). Now, using the same word to express two closely connected conceptions, is a sure sign that their difference has not been recognised, or at any rate not been firmly grasped ; for a mere accidental homonymous designation of two widely differing things is quite another matter. No where, however, does this error appear more conspicuously than in his definition of the sophism non causæ ut causa, παρὰ τὸ μὴ αίτιον ὡς αίτιον (reasoning from what is not cause as if it were cause), in the book "De sophisticis elenchis," c. 5. By αίτιον he here understands absolutely nothing but the argument, the premisses, consequently a reason of knowledge ; for this sophism consists in correctly proving the impossibility of something, while the proof has no bearing whatever upon the proposition in dispute, which it is nevertheless supposed to refute. Here, therefore, there is no question at all of physical causes. Still the use of the word αίτιον has had so much weight with modern logicians, that they hold to it exclusively in their accounts of the fallacia extra dictionem, and explain the fallacia non causæ ut causa as designating a physical cause, which is not the case. Beimarus, for instance, does so, and G. E. Schultze and Fries—all indeed of whom I have any knowledge. The first work in which I find a correct definition of this sophism, is Twesten's Logic. Moreover, in all other scientific works and controversies the charge of a fallacia non causæ ut causa usually denotes the interpolation of a wrong cause.
Sextus Empiricus presents another forcible instance of the way in which the Ancients were wont universally to confound the logical law of the reason of knowledge with the
