h all laws of nature have to be stated, and to secure that the
entities and relations thus exhibited are adequate for the expression of
all the relations between entities which occur in nature.

The third requisite, namely that of adequacy, is the one over which all
the difficulty occurs. The ultimate data of science are commonly assumed
to be time, space, material, qualities of material, and relations
between material objects. But data as they occur in the scientific laws
do not relate all the entities which present themselves in our
perception of nature. For example, the wave-theory of light is an
excellent well-established theory; but unfortunately it leaves out
colour as perceived. Thus the perceived redness--or, other colour--has
to be cut out of nature and made into the reaction of the mind under the
impulse of the actual events of nature. In other words this concept of
the fundamental relations within nature is inadequate. Thus we have to
bend our energies to the enunciation of adequate concepts.

But in so doing, are we not in fact endeavouring to solve a metaphysical
problem? I do not think so. We are merely endeavouring to exhibit the
type of relations which hold between the entities which we in fact
perceive as in nature. We are not called on to make any pronouncement as
to the psychological relation of subjects to objects or as to the status
of either in the realm of reality. It is true that the issue of our
endeavour may provide material which is relevant evidence for a
discussion on that question. It can hardly fail to do so. But it is only
evidence, and is not itself the metaphysical discussion. In order to
make clear the character of this further discussion which is out of our
ken, I will set before you two quotations. One is from Schelling and I
extract the quotation from the work of the Russian philosopher Lossky
which has recently been so excellently translated into English[4]--'In
the "Philosophy of Nature" I considered the subject-object called nature
in its activity of self-constructing. In order to understand it, we must
rise to an intellectual intuition of nature. The empiricist does not
rise thereto, and for this reason in all his explanations it is always
_he himself_ that proves to be constructing nature. It is no wonder,
then, that his construction and that which was to be constructed so
seldom coincide. A _Natur-philosoph_ raises nature to independence, and
makes it construct itself, and he