Movements have direction; would there be any sense in talking of the north-easterly direction of one's thought on the morality of
revenge?^3It is true that whereas matter can exist apart from consciousness, consciousness cannot exist apart from matter, i.e.,
apart from a living organism. But this dependence of consciousness on matter does not in any way support the
claim that they are identical. On the contrary: as more than one critic of reductive materialism has pointed out, it is
reasonable to speak of one thing being dependent on another only if they are not identical.
In the writings of Aristotle, one finds a treatment of consciousness (and of life) that is signally superior to the
approach of most "moderns." There are many respects in which, when one studies the history of philosophy,
moving from Aristotle to Descartes to the present, one feels as though history were moving backward, not
forward—as if most of Aristotle's successors down through the ages have been pre-Aristotelians. Aristotle is
neither a mystic nor a "materialist"; he does not regard consciousness as supernatural, as an incomprehensible and
irksome presence in a mechanistic universe, to be banished by reduction to the blind motion of inanimate particles,
like an exile whom the authorities found discomfiting. To Aristotle, consciousness is a natural fact of reality, the
characteristic attribute of certain entities. In this issue, his approach is far more "empirical'' than that of most
"empiricists." His example should serve as a lead to those who desire to pursue a genuinely scientific study of
conscious living organisms.^4
The only consciousness of which one has direct and immediate knowledge is one's own. One knows the
consciousness of other beings only indirectly, inferentially, through outward physical expression in action. This
does not mean that one can achieve exhaustive knowledge of the nature and laws of mental activity, merely by
introspection. It means that each man can directly experience only his own consciousness; the consciousness of
other beings can never be the object of his direct perception of experience.
Communication among men concerning psychological states is possible because each man has his own inner
psychological laboratory to which he can refer.