Kant's argument is that, while the soul may not be a collection of parts extended in space (therefore, not an extended quantity), it still has intensive quantity and, like a sound, it can gradually lose more and more existence until it fades out of existence altogether.

Is Kant's objection sound? We don't think so. As Roderick Chisholm points out:

(Kant) thought that some things could have more existence than others. It is as though he thought that there is a path between be…