the whole discussion between science and metaphysics turns on, or harks back
to the discussion between function and structure; and it is the latter, in
the sense in which I mean the word, that has had of late a too large share
of our attention.

The enterprise on which we are all of us embarked,--whether we define it as
an investigation, pure and simple, into human nature and human motives, or
as a therapeutic attempt to relieve invalids of their symptoms,--is a larger
one than it is commonly conceived of as being. Each physician and each
investigator has, indeed, the right to say that for practical reasons he
prefers to confine his attention to some single portion of one or the other
of these tasks, be it never so small. But each one should regard himself as
virtually under an obligation to recognize the respects in which this chosen
task is incomplete. Every physicist is aware that there is some form of
energy underlying, or rather expressing itself in, light and heat and
gravitation. Physicists do not study this form of energy, not because they
do not wish to but simply because they cannot do so by the only methods that
they are allowed to use. But, as a reaction of defense, they sometimes
assert that no one else can do so either, that this underlying energy cannot
be explained. To say this is, however, in my judgment, to misappreciate
what an explanation is.

To explain any matter is to discover the points of similarity, or virtual
identity, between the matter studied and ourselves. But in order to do this
thoroughly, or rather in order to do it with relation to the essential
nature of some form of energy (the "Libido," for example, considered as an
unpicturable force) one must first consider what we, the investigators, are,
not at our less good, but at our best. It is with us, as given, with our
best qualities regarded as defining in part the Q. E. D. of the experiment,
that the investigation must begin. The nature of any and every form of real