Alexander of Aphrodisias and the Heterodox dictum de omni et de nullo

Aristotle's explanation of what is said ‘of every’ and ‘of none’ has been interpreted either as involving individuals (of which something is said ‘of every’, or of which something is said ‘of none’), or as regarding exclusively universal terms. I claim that Alexander of Aphrodisias endorsed this latter interpretation of the dictum de omni et de nullo. This interpretation affects our understanding of Alexander's syllogistic: as a matter of fact, Alexander maintained that the dictum de omni et de nullo is one of the core principles of syllogistic.