ch its own deductions
are carried on. Psychology, the science of finite individual minds,
assumes as its data (1) _thoughts and feelings_, and (2) _a physical
world_ in time and space with which they coexist, and which (3) _they
know_. Of course, these data themselves are discussable; but the
discussion of them (as of other elements) is called metaphysics and
falls outside the province of this book."

This is an admirable statement of the scope of psychology as a natural
science, and also of the relations of metaphysics to the sciences. But
it would not be fair to Professor James to take this sentence alone,
and to assume that, in his opinion, it is easy to separate psychology
altogether from philosophy. "The reader," he tells us in the next
paragraph, "will in vain seek for any closed system in the book. It is
mainly a mass of descriptive details, running out into queries which
only a metaphysics alive to the weight of her task can hope
successfully to deal with." And in the opening sentence of the preface
he informs us that some of his chapters are more "metaphysical" than is
suitable for students going over the subject for the first time.

That the author is right in maintaining that it is not easy to draw a
clear line between philosophy and psychology, and to declare the latter
wholly independent, I think we must concede. An independent science
should be sure of the things with which it is dealing. Where these are
vague and indefinite, and are the subject of constant dispute, it
cannot march forward with assurance. One is rather forced to go back
and examine the data themselves. The beaten track of the special
science has not been satisfactorily constructed.

We are forced to admit that the science of psychology has not yet
emerged from the state in which a critical examination of its
foundations is necessary, and that the construction of the beaten path
is still in progress. This I shall try to make clear by illustrations.

The psychologist studies the mind, and his ultimate appeal must be to
introspection, to a direct observation of mental phenomena, and of
their relations to external things. Now, if the observation of mental
phenomena were a simple and an easy thing; if the mere fact that we are
conscious of sensations and ideas implied that we are _clearly_
conscious of them and are in a position to describe them with accuracy,
psychology would be a much more satisfactory science than it is.

Bu