18. There are other questions calling for consideration:
First: Are both Acts and motions to be included in the category of Action, with the distinction that Acts are momentary while Motions, such as cutting, are in time? Or will both be regarded as motions or as involving Motion?
Secondly: Will all activities be related to passivity, or will some- for example, walking and speaking- be considered as independent of it?
Thirdly: Will all those related to passivity be classed as motions and the independent as Acts, or will the two classes overlap? Walking, for instance, which is an independent, would, one supposes, be a motion; thinking, which also does not essentially involve "passivity," an Act: otherwise we must hold that thinking and walking are not even actions. But if they are not in the category of Action, where then in our classification must they fall?
It may perhaps be urged that the act of thinking, together with the faculty of thought, should be regarded as relative to the thought object; for is not the faculty of sensation treated as relative to the sensible object? If then, we may ask, in the analogue the faculty of sensation is treated as relative to the sensible object, why not the sensory act as well? The fact is that even sensation, though related to an external object, has something besides that relation: it has, namely, its own status of being either an Act or a Passion. Now the Passion is separable from the condition of being attached to some object and caused by some object: so, then, is the Act a distinct entity. Walking is similarly attached and caused, and yet has besides the status of being a motion. It follows that thought, in addition to its relationship, will have the status of being either a motion or an Act.