t happenings are the
brain-changes--which are causally connected--and that our thoughts, or
corresponding states of consciousness, merely accompany the
brain-changes, just as the shadow of a horse may be said to accompany
the horse.

The objections of this doctrine are:--

(_a_) That it is just as inconceivable to believe or imagine that
brain-changes generate consciousness as it is to imagine that
consciousness generates brain-changes.

(_b_) The law of Conservation is preserved at the expense of the law of
Causality. For, if no part of the cause passed over into the effect (the
state of consciousness), the law of Causality would be violated.

(_c_) The appearance of consciousness, at some definite point in the
course of the evolution of the animal kingdom constitutes a breach of
continuity.

For these and other reasons epiphenomenalism is today held by few, if
any, philosophers.

_3rd. Psycho-Physical Parallelism._--This is the doctrine maintained by
Muensterberg and others. It contends that brain-changes and states of
consciousness are merely coincidental in point of time, and do not ever
influence each other. Their relation is that of mere coincidence or
concomitance, and not causation. The two flow along, side by side,
without in any way interfering with one another.

As regards this doctrine, it need only be pointed out that, were it
true, mind and body could never influence one another, since they are
not causally connected. Yet, if there be no connection, how is it that
they correspond so exactly?--for, as James said, "It is quite
inconceivable that consciousness should have _nothing to do_ with a
business which it so faithfully attends."

_4th. Phenomenalistic Parallelism._--This is the theory maintained by
Kant, Spinoza, and others. It maintains that both brain and
consciousness (or mind and body) are but two different expressions of
one underlying reality--just as the convex and concave surfaces of a
sphere are but two expressions of an underlying reality. As to the
nature of this reality, Kant and Herbert Spencer were content to call it
X or the unknown, while Spinoza maintained that it was God.

Analogies which are held to support this doctrine are, however,
extremely defective; but the subject is too lengthy and technical to
elucidate in detail here.

_5th. Psychical Monism._--This doctrine contends that consciousness is
the only reality--the material world being external appearance only.
Tho