ed by the fact of real
psychical causality. We need not here concern ourselves with the difficult
question, whether the mind can of itself act upon the body, and through it
upon the external world. But in the logical consistence of naturalism
there was implied not only a negative answer to this last question, but
also a denial of the causality of the psychical, even within itself and
its own domain. This is well illustrated in the figure of the cloud
shadows. In consciousness state follows upon state, a upon b, b upon c.
According to naturalism, b is not really the result of a, nor c of b, for
in that case there would be independence of phenomena, and distinctness of
laws in the psychical. But as all the states, a, b, and c, of the cloud
shadows, depend upon states _a_, _b_, and _c_, of the clouds themselves,
but do not themselves form a concatenation of causes, so all the states of
the mind depend upon those of the body, in which alone there is a true
chain of causes because they alone have true reality.

This is a complete distortion of the facts of the case. It would never be
possible to persuade oneself or any one else that the arm, for instance,
did not bend simply because we willed that it should. And it is still less
possible to doubt that there are sequences of causes within the psychical,
that in the world of thought and feeling, of desire and will, one thing
calls up another, awakes it, impels it onwards, and influences it. Indeed,
the mode of influence is peculiarly rich, subtle, and certain. Mental
images and experiences arouse joy or sorrow, admiration or repulsion. One
image calls up another, forces it to appear according to quite peculiar
laws, or may crowd it out. Feelings call up desires, desires lead to
determination. Good news actually causes joy, this is actually
strengthened to willing, and the new situation gives rise to actual
resolves. All this is so obvious and so unquestionable that no naturalism
can possibly prevail against it. It has also long been made the subject of
special investigation and carefully regulated experiment, and it is one of
the chief subjects of modern psychological science. And especially as
regards the different forms of "association of ideas," the particular laws
of this psychical causality have been established.

It cannot be denied, however, that this psychology of association has
itself in a deeper sense certain dangers from the point of view of the
freedom of the mind