60 THE GROUNDWORK OF SCIENCE

is "this thing here") and also the kind to which it pertains

(that it is a member of a group, which, as a group, exists

only in the mind).

How different is the intellectual apprehension from the

sensuous affection is clear from the fact that changes in such

sensuous affections may only render the intellectual appre-

hension a more complete and perfect unity. Thus, if a

solid cube be suspended by a string and then turned

round before us, we can never see all its surfaces at once,

and its square faces, as we see them in perspective, do not

look square but lozenge-shaped. Nevertheless, these incom-

plete, defective signs, not only serve to give us an accurate

perception of the cube, but its revolution, though it changes

our sensuous impressions, only makes our intellectual

conception more complete and stable while the former

changes, the latter remains the same throughout.

Thus every material object whereof our senses can take

cognizance, has various qualities its size, shape, solidity,

colour, etc. and acts upon our senses accordingly.

Its qualities affect us in response to our activities of eye,

ear, hand, etc. Our two eyes form two slightly discordant

images of it, and our hands and arms may give us numbers

of synchronous and successive feelings respecting it. Simul-

taneously with these sensuous impressions, we have a

perception of the object and its qualities. But that percep-

tion is by no means correspondingly multiform. The

perception is one intellectual cognition resulting from a

multitude of sensations and reminiscences. Our attention

may, of course, be directed to any one of its qualities, but

if so, what we then directly perceive is no longer the thing

itself but the quality in question.

As it is with the revolving cube, so also changes produced

by our own movements may make our intellectual cognition

of what surrounds us more unchanging. When walking

is "this thing here") and also the kind to which it pertains

(that it is a member of a group, which, as a group, exists

only in the mind).

How different is the intellectual apprehension from the

sensuous affection is clear from the fact that changes in such

sensuous affections may only render the intellectual appre-

hension a more complete and perfect unity. Thus, if a

solid cube be suspended by a string and then turned

round before us, we can never see all its surfaces at once,

and its square faces, as we see them in perspective, do not

look square but lozenge-shaped. Nevertheless, these incom-

plete, defective signs, not only serve to give us an accurate

perception of the cube, but its revolution, though it changes

our sensuous impressions, only makes our intellectual

conception more complete and stable while the former

changes, the latter remains the same throughout.

Thus every material object whereof our senses can take

cognizance, has various qualities its size, shape, solidity,

colour, etc. and acts upon our senses accordingly.

Its qualities affect us in response to our activities of eye,

ear, hand, etc. Our two eyes form two slightly discordant

images of it, and our hands and arms may give us numbers

of synchronous and successive feelings respecting it. Simul-

taneously with these sensuous impressions, we have a

perception of the object and its qualities. But that percep-

tion is by no means correspondingly multiform. The

perception is one intellectual cognition resulting from a

multitude of sensations and reminiscences. Our attention

may, of course, be directed to any one of its qualities, but

if so, what we then directly perceive is no longer the thing

itself but the quality in question.

As it is with the revolving cube, so also changes produced

by our own movements may make our intellectual cognition

of what surrounds us more unchanging. When walking