Primary and secondary qualities
The "new way of ideas" is thus hard put to it in accounting
for the universal element in knowledge; it has even greater difficulties
to face in defending the reality of knowledge. And, in the latter
case, the author does not see the difficulties so clearly. His view
is that the simple idea is the test and standard of reality. Whatever
the mind contributes to our ideas removes them further from the
reality of things; in becoming general, knowledge loses touch with
things. But not all simple ideas carry with them the same significance
for reality. Colours, smells, tastes, sounds, and the like are simple
ideas, yet nothing resembles them in the bodies themselves; but,
owing to a certain bulk, figure, and motion of their insensible
parts, bodies have "a power to produce those sensations in
us." These, therefore, as called "secondary qualities
of bodies." On the other hand, "solidity, extension, figure,
motion or rest, and number" are also held by Locke to be simple
ideas; and these are resemblances of qualities in body; "their
patterns do really exist in the bodies themselves"; accordingly,
they are "primary qualities of bodies." In this way, by
implication if not expressly, Locke severs, instead of establishing,
the connection between simple ideas and reality. The only ideas
which can make good their claim to be regarded as simple ideas have
nothing resembling them in things. Other ideas, no doubt, are said
to resemble bodily qualities (an assertion for which no proof is
given and none is possible); but these ideas have only a doubtful
claim to rank as simple ideas. Locke's prevailing tendency is to
identify reality with the simple idea, but he sometimes comes close
to the opposite view that the reference to reality is the work of
thought. |
