llect.

The further question as to the nature of the connection is interesting,
but it relates to matters of far less consequence to the naturalist than
the central fact of the invariable relation which does exist. Throughout
the centuries many philosophers and naturalists of numerous peoples have
endeavored to explain the connection in question in ways that have been
largely determined by the changing states of knowledge of various periods,
as well as by differences in individual temperament. Three general
conceptions have been developed: first, that the material and mental
phenomena _interact_; second, that they are _parallel_; and third, that
they are _one_.

According to the first view, the individual thoughts and feelings forming
elements in the chain of consecutive consciousness are affected by the
events in the material physiology of the brain as a physical structure;
the latter in turn react upon the psychical or mental elements. Thus there
would be two complete series of phenomena, which are interdependent and
interacting at all times, although each would be in itself a complete
chain of elements.

The second interpretation is that the two series of events--namely, the
physical processes of the brain and the elements of consciousness--are
completely _independent_ but entirely parallel. As one writer has put the
case, it is as though we had two clocks whose machinery worked at the same
rate and whose relationships were such that "one clock would give the
proper number of strokes when the hands of the other pointed to the hour."
But in my opinion this attempted explanation of the relation of mind to
matter evades the whole question, as it does not account for the
dependence of the former upon the latter, but merely assumes the existence
of a more ultimate and unknown group of causes for a parallelism in the
rates of operation of two series of things regarded as disconnected.

The third conception recommends itself to many on account of its greater
simplicity. Formulated as the doctrine of monism, it states that the mind
and its material basis are merely different _aspects_ of one and the same
thing, and that there is only one series of connected elements which are
known to us directly as the current of our thoughts and indirectly as the
physiological processes going on mainly in the cerebrum. Thus mind is
purely subjective, the brain is only mediately objective. It is because
the mental and the material are so