On Memory And Reminiscense   

or affection of one of these, conditioned by lapse of time. As already

observed, there is no such thing as memory of the present while

present, for the present is object only of perception, and the future,

of expectation, but the object of memory is the past. All memory,

therefore, implies a time elapsed; consequently only those animals

which perceive time remember, and the organ whereby they perceive time

is also that whereby they remember.

The subject of 'presentation' has been already considered in our

work On the Soul. Without a presentation intellectual activity is

impossible. For there is in such activity an incidental affection

identical with one also incidental in geometrical demonstrations.

For in the latter case, though we do not for the purpose of the

proof make any use of the fact that the quantity in the triangle

(for example, which we have drawn) is determinate, we nevertheless

draw it determinate in quantity. So likewise when one exerts the

intellect (e.g. on the subject of first principles), although the

object may not be quantitative, one envisages it as quantitative,

though he thinks it in abstraction from quantity; while, on the

other hand, if the object of the intellect is essentially of the class

of things that are quantitative, but indeterminate, one envisages it

as if it had determinate quantity, though subsequently, in thinking

it, he abstracts from its determinateness. Why we cannot exercise

the intellect on any object absolutely apart from the continuous, or

apply it even to non-temporal things unless in connexion with time, is

another question. Now, one must cognize magnitude and motion by

means of the same faculty by which one cognizes time (i.e. by that

which is also the faculty of memory), and the presentation (involved

in such cognition) is an affection of the sensus communis; whence this

follows, viz. that the cognition of these objects (magnitude, motion

time) is effected by the (said sensus communis, i.e. the) primary

faculty of perception. Accordingly, memory (not merely of sensible,

but) even of intellectual objects involves a presentation: hence we