is
disturbance, being perceptible to me, would be a physical fact
accompanying the volition, and could not be volition itself, which
is not perceptible to me. Whether there is such a disturbance of
the physical laws or no is a question of fact to which we have the
best of reasons for giving a negative answer; but the assertion
that another man's volition, a feeling in his consciousness which
I cannot perceive, is part of the train of physical facts which I
may perceive,--this is neither true nor untrue, but nonsense; it is
a combination of words whose corresponding ideas will not go
together[8].'

And seeing that the correlatives are in each case the same, it is
similarly 'nonsense' to assert the converse proposition: or, in other
words, it is equally nonsense to speak of mental action causing cerebral
action, or of cerebral action causing mental action--nonsense of the
same kind as it would be to speak of the _Pickwick Papers_ causing a
storm at sea, or the eruption of a volcano causing the forty-seventh
proposition in the first book of Euclid.

We see, then, that two of the three possible theories of things contain
the elements of their own destruction: when carefully analyzed, both
these theories are found to present inherent contradictions. On this
account the third, or only alternative theory, comes to us with a large
antecedent presumption in its favour. For it comes to us, as it were, on
a clear field, or with the negative advantage of having no logical
rivals to contend with. The other two suggestions having been weighed in
the balance and found wanting, we are free to look to the new-comer as
quite unopposed. This new-comer must, indeed, be interrogated as
carefully as his predecessors, and, like them, must be judged upon his
own merits. But as he constitutes our last possible hope of solving the
question which he professes himself able to solve, the absolute failure
of his predecessors entitles him to a patient hearing. By the method of
exclusion his voice is now the only voice that remains to be heard, and
unless it can speak to better purpose than the others, we shall have no
alternative but to abandon the facts as inexplicable, or to confess that
it is necessarily impossible for the human mind ever to arrive at any
theory of things.

Before proceeding to state or to examine this third and last of the
suggested theories, it is desirable--in order still fur