rather too far in physics, by assuming the current science to be literally
true, so, in the realm of imagination, he retrenched somewhat illiberally
our legitimate possessions. Strange that as modern philosophy transfers
the visible wealth of nature more and more to the mind, the mind should
seem to lose courage and to become ashamed of its own fertility. The
hard-pressed natural man will not indulge his imagination unless it poses
for truth; and being half aware of this imposition, he is more troubled at
the thought of being deceived than at the fact of being mechanised or
being bored: and he would wish to escape imagination altogether. A good
God, he murmurs, could not have made us poets against our will.

Against his will, however, Locke was drawn to enlarge the subjective
sphere. The actual existence of mind was evident: you had only to notice
the fact that you were thinking. Conscious mind, being thus known to
exist directly and independently of the body, was a primary constituent of
reality: it was a fact on its own account.[6] Common sense seemed to
testify to this, not only when confronted with the "I think, therefore I
am" of Descartes, but whenever a thought produced an action. Since mind
and body interacted,[7] each must be as real as the other and, as it were,
on the same plane of being. Locke, like a good Protestant, felt the right
of the conscious inner man to assert himself: and when he looked into his
own mind, he found nothing to define this mind except the ideas which
occupied it. The existence which he was so sure of in himself was
therefore the existence of his ideas.

Here, by an insensible shift in the meaning of the word "idea", a
momentous revolution had taken place in psychology. Ideas had originally
meant objective terms distinguished in thought-images, qualities,
concepts, propositions. But now ideas began to mean living thoughts,
moments or states of consciousness. They became atoms of mind,