To such most general genera there are subjected individuals that are really distinct from the individuals of another most general genus, [and] of which [this genus] is properly and directly predicated; for example, we can truly assert ‘This is [a] when’ pointing to the relation which is caused by the motion of the first movable in the inferior things, so that, if that individual had a distinct proper name imposed on it, one could just as truly respond to the question ‘What is it?’ by saying: ‘[A] when,’ as one can reply to the question ‘What is it?’ asked about a man, by saying: ‘A substance.’