n the other. So far as
the mortality of the soul is concerned, he may be either a spiritualist
or a materialist But spiritualism or materialism is to him only an
intellectual pastime. It is not his trade. In his actual work he seeks
only practical results, and so confines himself wholly to the actual
facts of human experience.

The practical scientist knows that as between two given facts, and
_only_ as between these two, one may be the "cause" of the other. But he
is not interested in the "creative origin" of material things. He does
not attempt to discover "first" causes.

[Sidenote: Science of Cause and Effect]

The practical scientist ascribes all sorts of qualities to electricity
and lays down many laws concerning it without having the remotest idea
as to what, in the last analysis, electricity may actually be. He is not
concerned with ultimate truths. He does his work, and necessarily so,
upon the principle that for all practical purposes he is justified in
using any given assumption as a working hypothesis if everything happens
just as if it were true.

The practical scientist applies the term "cause" to any object or event
that is the invariable predecessor of some other object or event.

For him a "cause" is simply any object or event that may be looked upon
as forecasting the action of some other object or the occurrence of some
other event.

The point with him is simply this, Does or does not this object or this
event in any way affect that object or that event or determine its
behavior?

[Sidenote: Causes and "First" Causes]

No matter where you look you will find that every fact in Nature is
relatively cause and effect according to the point of view. Thus, if a
railroad engine backs into a train of cars it transmits a certain amount
of motion to the first car. This imparted motion is again passed on to
the next car, and so on. The motion of the first car is, on the one
hand, the effect of the impact of the engine, and is, on the other hand,
the "cause" of the motion of the second car. And, in general, what is an
"effect" in the first car becomes a "cause" when looked at in relation
to the second, and what is an "effect" in the second becomes a "cause"
in relation to the third. So that even the materialist will agree that
"cause" and "effect" are relative terms in dealing with any series of
facts in Nature.

[Sidenote: A Common Platform for All]

A man may be either a spiritualist, believing tha