lf as follows;[1] "It may be difficult to
ascertain the exact point or surface at which the mind and body come
together and influence each other, in particular, how far into the body
(Descartes without proof thought it to be in the pineal gland), but it
is certain, that when they do meet mind knows body as having its
essential properties of extension and resisting energy."

How can an immaterial thing be located at some point or surface within
the body? How can a material thing and an immaterial thing "come
together" at a point or surface? And if they cannot come together,
what have we in mind when we say they interact?

The parallelist, for it is he who opposes interactionism, insists that
we must not forget that mental phenomena do not belong to the same
order as physical phenomena. He points out that, when we make the word
"interaction" cover the relations of mental phenomena to physical
phenomena as well as the relations of the latter to each other, we are
assimilating heedlessly facts of two different kinds and are
obliterating an important distinction. He makes the same objection to
calling the relations between mental phenomena and physical phenomena
_causal_. If the relation of a volition to the movement of the arm is
not the same as that of a physical cause to its physical effect, why,
he argues, do you disguise the difference by calling them by the same
name?

37. THE DOCTRINE OF THE PARALLELIST.--Thus, the parallelist is a man
who is so impressed by the gulf between physical facts and mental facts
that he refuses to regard them as parts of the one order of causes and
effects. You cannot, he claims, make a single chain out of links so
diverse.

Some part of a human body receives a blow; a message is carried along a
sensory nerve and reaches the brain; from the brain a message is sent
out along a motor nerve to a group of muscles; the muscles contract,
and a limb is set in motion. The immediate effects of the blow, the
ingoing message, the changes in the brain, the outgoing message, the
contraction of the muscles--all these are physical facts. One and all
may be described as motions in matter.

But the man who received the blow becomes conscious that he was struck,
and both interactionist and parallelist regard him as becoming
conscious of it when the incoming message reaches some part of the
brain. What shall be done with this consciousness? The interactionist
insists that it must be regarded a