al animal spirits, you can show that in places where through
settlements or municipal action gymnasiums have been provided, the
number of arrests of boys and young men has greatly fallen off, you have
established the grounds for an inference of cause and effect which gives
your argument a wholly new strength. In the case of the argument for a
return to a classical course in a college, this sequence of cause and
effect would be very difficult to establish, for here you would be deep
down in the most complex and subtle region of human nature. Wherever it
is possible, however, lead the inference from a classification or
generalization on to an inference of cause and effect.

38. Induction and Deduction. Our next step is to consider how we
get the generalizations on which we base so much of our reasoning. As we
have seen, the science which deals with the making of them, with their
basis, and with the rules which govern inferences made from them is
logic.

Logicians generally distinguish between two branches of their science,
inductive and deductive reasoning. In inductive reasoning we pass from
individual facts to general principles; in deductive reasoning we pass
from general principles to conclusions about individual facts. The
distinction, however, draws less interest in recent times than formerly,
and logicians of the present generation tend to doubt whether it has any
vital significance.[33] They point out that in practice we
intermingle the two kinds almost inextricably, that the distinction
between facts and principles is temporary and shifting, and that we
cannot fit some of the common forms of inference into these categories
without difficult and complicated restatement.

Nevertheless, as deductive logic and inductive logic are ancient and
time-honored terms which have become a part of the vocabulary of
educated men, it is worth while to take some note of the distinction
between them, I shall not attempt here to do more than to explain a few
of the more important principles. I shall begin with inductive logic,
since that is the branch which deals with the making of generalizations
from individual fact, and therefore that which has most concern in the
arguments of the average man in his passage through life.

39. Inductive Reasoning. In inductive reasoning we put individual
facts and cases together into a class on the basis of some definable
similarity, and then infer from them a general principle. The types of