  In this passage Metochites seems to contend that Aristotle’s argument against self-movement in Physics 7.1 and 8.5 entails the proposition that “what moves itself will not cease to do so,” which is used as one of the premises of an argument for the immortality of the soul. This latter argument is apparently strongly inspired by the first part of the proof of immortality in Socrates’ palinode in Plato’s Phaedrus (245c5–8). It seems to be an “ontological” kind of argument. That is to say, it attempts to show that the (eternal) existence of the soul follows from its nature. The soul’s nature is defined precisely as its movement, whereby it moves itself. The idea is obviously that since the mover and the moved thing, if they are identical, cannot be disconnected, there will always be sufficient reason that the moved thing is moved (because there will always be a mover connected with it) and that the mover causes movement (because there will always be something there for it to move). Now, what seems to be the other premise of this argument, namely the proposition that the soul moves itself, is refuted by Aristotle in De anima 1.3–4 on the strength of the very proposition established in Physics 7.1 and 8.5 and cited by Metochites in the preceding paragraph, namely that movement is necessarily an irreflexive relation. The question is, then: what reason, if any, can Metochites have for thinking that the proposition that self-movement is eternal follows from (an argument containing) the proposition that self-movement does not exist?