is what we aim at, it is of importance that we should make sure
of cause and effect as matter of fact in the sequence of events.

One large department of Inductive Logic, the so-called Experimental
Methods, is designed to help us in thus making sure, _i.e._, in
ascertaining causal sequence as a matter of fact. It is assumed
that by careful observation of the circumstances, we can distinguish
between mere simple sequence and causal sequence or consequence,
and methods are recommended of observing with the proper precautions
against error.

Observe that these methods, though called Inductive, are not concerned
with arriving at general propositions. The principle we go upon is
simply this, that if it can be ascertained as matter of fact that a
certain thing is related to another as cause and effect, we may count
upon the same relation as holding in unobserved Nature, on the general
ground that like causes produce like effects in like circumstances.

Observe, also, that I deliberately speak of the causal relation as
a relation among phenomena. Whether this use of the words cause and
effect is philosophically justifiable, is a question that will be
raised and partly discussed later on. Here I simply follow the common
usage, in accordance with which objects of perception, _e.g._, the
administration of a drug and the recovery of a patient, are spoken of
as cause and effect. Such observable sequences are causal sequences in
the ordinary sense, and it is part of the work of Science to observe
them. I do not deny that the _true_ cause, of the cause that
science aims ultimately at discovering, is to be found in the latent
constitution or composition of the things concerned. Only that, as we
shall see more precisely, is a cause of another description. Meantime,
let us take the word to cover what it undoubtedly covers in ordinary
speech, the perceptible antecedent of a perceptible consequent.

Strictly speaking, as we shall find, Science has only one method of
directly observing when events are in causal sequence. But there are
various indirect methods, which shall be described in some sort of
order.

For the practical purposes of life, a single ascertained causal
sequence is of little value as a basis of inference, because we can
infer only to its repetition in identical circumstances. Suppose our
village matron had been able to ascertain as a matter of fact--a feat
as we shall find not to be achieved by direct observation--t