e.g.,"I am enjoying myself" entails "I have enjoyed myself""I am gazing at the statue" entails "I have gazed at the statue";and X-ing is a kinesis ("movement") Just in case"I am X-ing" entails "I have not X-ed,"e.g.,"I am learning" entails "I have not learned,""I am walking from the library to Nassau Hall" entails"I have not walked from the library to Nassau Hall." Various qualifications have to be made at once. First, "I have enjoyed myself must not be taken to imply (as it can do, even in Greek)² that I have stopped enjoying myself. (I will simply take it that it need not imply this, as it need not in Greek.) Similarly for "I have gazed at the statue." With "learn" and "walk from the library to Nassau Hall," on the other hand, the perfect tense entails that I have stopped doing the action which was going on when the present tense truly applied. Second, the perfect-tensed expressions in these examples ("I have learned," etc.) should not be construed as frequentative or as referring to past occasions of learning, etc., but rather as referring to the very same action (of learning, etc.) as that referred to in the present-tensed expressions in the examples ("I am learning," etc.). Doubtless more qualifications still need to be added to make the examples right. But these will perhaps suffice for purposes of showing the possibility of our making such a distinction. I shall in any case, later in the paper, be challenging this exposition of the distinction in many important details (including the translation of energeia as "activity": thus I shall continue to use the Greek words, energeia and kinesis—"movement"—until, later in the paper, I establish the translation I favour for energeia). In an appendix to this paper I have given a new translation of Aristotle's actual words on the subject in Met. 66, a translation which departs in a number of respects from standard translations.