ughts are causally connected, but not physical events. (The doctrine
is thus the exact inverse of epiphenomenalism.)

In refutation of this theory, it may be pointed out that, if
brain-changes are thus caused by, or are the outer expressions of,
thought--why not muscular changes, and in fact all physical phenomena
throughout the world everywhere? For we cannot rationally draw the line
of distinction here. Such is the logical outcome of the theory--and has,
in fact, been accepted in this form by Fechner and others.

While many philosophers are inclined to accept this view, it may be
stated that the physical scientists are, naturally, repelled by it, and
so is common sense!

_6th. Solipsism._--The contention of this theory is that nothing exists
save states of consciousness in the individual. Neither the material
world nor other minds exist, save in the mind of the individual. This
doctrine is so opposed to common sense and daily experience that it is
unnecessary to dwell upon it.

_7th. Inter-Actionism (Animism)._--Here we have the world-old notion of
soul and body existing as separate entities, influencing each other.
Mind is here supposed to influence matter, and utilize it for the
purposes of its manifestation.

That there are many facts difficult to account for on this theory cannot
be doubted. Heredity and the origin of life must be taken into account;
the "inconceivability" of the process has some weight; and the apparent
infringement of the law of Conservation of Energy is a serious
objection. Further, it may be urged, what evidence have we that
consciousness can exist apart from brain-functioning? And, it may be
said, apart from the facts offered by "psychical research," so-called,
there is no evidence, strictly speaking. Hence the importance of these
phenomena, if true. But the greatest objection to the doctrine of
inter-actionism is doubtless that drawn from the law of the Conservation
of Energy, which says that, inasmuch as mind is a non-physical energy,
inasmuch as matter cannot be affected by a non-physical cause,
brain-changes cannot result from will, or the activities of the mind.

But once prove that the human will is a physical energy, and this
objection is readily disposed of. A physical energy is doubtless quite
capable of causing all the changes within the brain which we know to
exist within it--molecular, chemical, whatever they may be. It at once
removes this classical objection to the doctrin