ill take the form of
differential equations--or of finite-difference equations,
if the theory of quanta should prove correct.

It is probable that the whole science of mental occurrences, especially
where its initial definitions are concerned, could be simplified by the
development of the fundamental unifying science in which the causal laws
of particulars are sought, rather than the causal laws of those systems
of particulars that constitute the material units of physics. This
fundamental science would cause physics to become derivative, in the
sort of way in which theories of the constitution of the atom make
chemistry derivative from physics; it would also cause psychology to
appear less singular and isolated among sciences. If we are right in
this, it is a wrong philosophy of matter which has caused many of the
difficulties in the philosophy of mind--difficulties which a right
philosophy of matter would cause to disappear.

The conclusions at which we have arrived may be summed up as follows:

I. Physics and psychology are not distinguished by their material. Mind
and matter alike are logical constructions; the particulars out of which
they are constructed, or from which they are inferred, have various
relations, some of which are studied by physics, others by psychology.
Broadly speaking, physics group particulars by their active places,
psychology by their passive places.

II. The two most essential characteristics of the causal laws which
would naturally be called psychological are SUBJECTIVITY and MNEMIC
CAUSATION; these are not unconnected, since the causal unit in mnemic
causation is the group of particulars having a given passive place at
a given time, and it is by this manner of grouping that subjectivity is
defined.

III. Habit, memory and thought are all developments of mnemic causation.
It is probable, though not certain, that mnemic causation is derivative
from ordinary physical causation in nervous (and other) tissue.

IV. Consciousness is a complex and far from universal characteristic of
mental phenomena.

V. Mind is a matter of degree, chiefly exemplified in number and
complexity of habits.

VI. All our data, both in physics and psychology, are subject to
psychological causal laws; but physical causal laws, at least in
traditional physics, can only be stated in terms of matter, which is
both inferred and constructed, never a datum. In this respect psychology
is nearer to what actu