Numerical difference between something which changes and...

Numerical difference between something which changes and that into which it changes pertains only to its potential parts which continually become existent and nonexistent, although none of them has actual existence.

In other words, motion is not a collection of existents which come into existence one after the other, rather it is abstracted from the extension of a single existent and it is infinitely divisible, although the division of it in the external world involves the appearance of rest and the destruction of its unity.

The Existence of Motion In Lesson Fifty-One it was mentioned that a group of ancient Greek philosophers, such as Parmenides and Zeno of Elea denied that there was gradual change or motion. This position seems strange at first, and the question immediately arises in the mind of the reader or hearer as to whether they did not observe all these various motions?! Did they not themselves move around?! But by examining their words more carefully it becomes clear that the matter is not quite so simple.

Even the positions of some of those who believe in motion and stubbornly defend it (such as some Marxists) originate with the Eleatics! The secret of the matter is that they considered the changes called motion to be a collection of successive instantaneous changes. For example, the motion of a body from one point to another was considered to be the successive resting of the body at the points between the two assumed points.

In other words, they did not accept motion as something gradual and continuous, but rather as a collection of successive rests. Therefore, if someone else holds that motion has actual parts, in reality he has joined the ranks of those who deny motion. The truth is that the existence of motion as a single gradual thing is undeniable. Even some instances of it, such as the gradual changes of psychic qualities, can be perceived by infallible presentational knowledge.

The source of the error of the Eleatics are doubts that run counter to consciousness and self-evidence, and no uncertainty remains once these doubts are dispelled.