ment is
furnished by the common laws and forms of our exertional Activity by
means of which and in terms of which we all construct our conceptions of
the dynamic world of our environment.

* * * * *

It is from our dynamic Activity also that we derive our conception of
Force. Force, though it is studied scientifically in the measurement of
the great natural forces which operate constantly, is originally known
to us in the stress or pressure to which muscular exertion in contact
with a material body gives rise. Such a force if it could be correctly
measured, would record the rate at which Energy was undergoing
transmutation, and it is from such experience of pressure that our idea
of Force is originally derived.

The mass of bodies is usually measured by their weight, _i.e._ by
gravity. Its absolute measurement must be in terms of momentum. The true
estimate of the Energy of a body moving under the impulse of a constant
Force is stated in the formula 1/2MV{2}. To ascertain M, therefore, we
must have given F and V, and these are both conceptions the original
idea of which is derived from our exertional activity.

Quantity of Matter originally means the same as amount of resistance to
initiation of motion, at first estimated by the varying amount of
personal muscular energy required to effect the motion in question,
thereafter objectively and scientifically by comparison with some
independent standard whereby a more exact estimation can be attained
than was possible by a mere reference to the varying inferences of the
individual who might exert the force.

Space, Mass, Force are all therefore ideas which are furnished to us out
of our experience as potent actors, and the recognition of this great
truth provides us with the means of clearly apprehending and co-relating
our conceptions of the external world, the framework of our Knowledge.

The true distinction between a _percept_ and a _concept_ is just that a
percept is a concept associated with the dynamic system discovered in
and by our exertional activity.

In like manner we find here the true solution of the many questions
which have been raised as to the distinction between general and
abstract, singular and concrete terms.

Language expresses action: the roots of language are expressions of the
elementary acts which make up experience. They are therefore general.
Each applies to every act of the class in question. They are also