able as others
according to the mathematical theory, some physical law prevents them
from occurring so often. Now, stronger testimony may indeed be needed
to support the assertion of such a combination as, e.g. ten successive
throws of sixes at dice, because such a regular series is more likely
than an irregular series to be the result of design; and because even
the desire to excite wonder is likely to tempt men to assert the
occurrence falsely, though this probability must be estimated afresh in
every instance. But though such a series _seems_ peculiarly improbable,
it is only because the comparison is tacitly made, not between it and
any one particular previously fixed series of throws, but between all
regular and all irregular successions taken together. The fact is not in
itself more improbable; and no stronger evidence is needed to give it
credibility, apart from the reasons above mentioned, than in the case of
ordinary events.

BOOK IV.

OPERATIONS SUBSIDIARY TO INDUCTION.

CHAPTER I.

OBSERVATION AND DESCRIPTION.

The mental process which Logic deals with, viz. the investigation of
truth by means of evidence, is always a process of Induction. Since
Induction is simply the extension to a class of something observed to be
true of certain members of it, Observation is the first preliminary to
it. It is, therefore, right to consider, not indeed how or what to
observe (for this belongs to the art of Education), but under what
conditions observation is to be relied on. The sole condition is, that
the supposed observation should really be an observation, and not an
inference, whereas it is usually a compound of both, there being, in our
propositions, besides observation which relates only to the sensations,
an inference from the sensations to the objects themselves. Thus
so-called errors of sense are only erroneous inferences from sense. The
sensations themselves must be genuine; but, as they generally arise on a
certain arrangement of outward objects being present to the organs, we,
as though by instinct, infer this arrangement even when not existing.
The sole object, then, of the logic of observation, is to separate the
inferences from observation from the observations themselves, the only
thing really observed by the mind (to waive the metaphysical problem as
to the _perception_ of objects) being its own feelings or states of
consciousness, outward, viz. Sensations, and inward, viz. Thoughts,
Em