e of a
First Cause, the nature of which is variously explained. The empirical
school sees no difficulty in assuming a single event; but such a theory
seems to deny the validity of the original hypothesis. Theologians
assert a divine origin in the form of a personal self-existent creator,
while some metaphysical schools, preferring an impersonal First Cause,
substitute the doctrine of the Absolute (q.v.). All the explanations are
alike in this respect, that at a certain point they pass from the sphere
of the senses, the physical world, to a metaphysical sphere in which the
data and the intellectual operation of cognizing them are of a totally
different quality. For example, the causal connexion between drunkenness
and alcohol is not of the same observable character as that which is
inferred between the infinite First Cause and the whole domain of
sense-given phenomena.

A second metaphysical problem connected with causation arises when we
consider the nature of necessity. It is generally assumed when two
things are spoken of as cause and effect that their relation is a
necessary one, or, in other words, that given the cause the effect must
follow. The arguments connected with this problem belong to
psychological discussions of causation. It is sufficient here to state
that, in so far as causation is regarded as necessary connexion, it can
form no part of a purely empirical theory of existence. The senses can
say only that in all observed cases B has followed A, and this does not
establish necessary connexion. The idea of causation is a purely
intellectual (a priori) one.

The psychological problems connected with causation refer (1) to the
origin of the conception in our minds; (2) to the validity of the
conception. As regards the origin of the conception modern psychological
analysis does not carry us beyond the doctrine of Locke contained in his
chapter on "Power" (_Essay_, bk. ii. ch. 21), wherein he shows that the
idea of power is got from the knowledge of our own activity. "Bodies by
their causes," he says, "do not afford us so clear and distinct an idea
of active power as we have from reflection on the operation of our
minds." Putting Locke's doctrine into modern language, we may say that a
man has the conception of cause primarily because he himself is a cause.
The conception thus obtained we "project," that is, transfer to external
objects, so far as we may find it useful to do so. Thus it is by a sort
of analo