To clarify this: motion does not belong to the same genus as the presence in a location that it shares with rest. For a thing’s being in this spatial position or in that one is intelligible without considering whether it is moving. If we suppose that it came to rest in the second position, its presence there would belong to the same genus as its presence in the first. Motion itself, however, is something additional to the mere presence common to both.

He also rejected the second premise, basing his rejection on the following: if someone who says, “Being preceded by something is an accidental attribute,” means that it is not essential, there is no proof of that. If he means that it is accidental to what the two share, then an attribute accidental to their common element may be essential to the essence composed of that common element and the distinguishing element. Rationality, for example, is an accidental attribute of animality, not essential to it; yet it is essential to humanity, which is composed of animality and rationality.

Al-Rāzī might reply that one thing’s being preceded by another is merely a relational matter: it means that it comes after it. Such a relation is not an essential attribute. Consider, for example, two motions alike in essence, the second following the first. If they are alike in essence, the fact that one is preceded by something else while the other is not cannot be treated as an essential attribute distinguishing them.

One might say: both the argument and the objection rest on dividing the attributes inseparable from an essence into essential and accidental attributes, as some logicians do. Yet dividing the attributes inseparable from an essence into those that are essential and internal to it, and those that are accidental and external to it, is a position for which there is no proof; rather,