CHAPTER VI

CONDITIONS OF IMMEDIATE INFERENCE


§ 1. The word Inference is used in two different senses, which are often
confused but should be carefully distinguished. In the first sense, it
means a process of thought or reasoning by which the mind passes from
facts or statements presented, to some opinion or expectation. The data
may be very vague and slight, prompting no more than a guess or surmise;
as when we look up at the sky and form some expectation about the
weather, or from the trick of a man's face entertain some prejudice as
to his character. Or the data may be important and strongly significant,
like the footprint that frightened Crusoe into thinking of cannibals, or
as when news of war makes the city expect that Consols will fall. These
are examples of the act of inferring, or of inference as a process; and
with inference in this sense Logic has nothing to do; it belongs to
Psychology to explain how it is that our minds pass from one perception
or thought to another thought, and how we come to conjecture, conclude
and believe (_cf._ chap. i. § 6).

In the second sense, 'inference' means not this process of guessing or
opining, but the result of it; the surmise, opinion, or belief when
formed; in a word, the conclusion: and it is in this sense that
Inference is treated of in Logic. The subject-matter of Logic is an
inference, judgment or conclusion concerning facts, embodied in a
proposition, which is to be examined in relation to the evidence that
may be adduced for it, in order to determine whether, or how far, the
evidence amounts to proof. Logic is the science of Reasoning in the