Note 56 — Chapter V · OF THE VERB.
Reading edition
In Latin the imperfect potential is frequently employed in the same manner to denote present time; thus, irem si vellem, expresses present liberty and inclination. And the same analogy obtains in Latin; for we say, either, tu, si hic sis, aliter sentias, or tu, si hic esses, aliter sentires. In such examples, it is intended to signify either the coexistence of two circumstances, or the one as the immediate consequence of the other. An identity of tense, therefore, best expresses contemporary events.