There is a well-known incident in one of Moliere's plays, where the
author makes the hero express unbounded delight on being told that he
had been talking prose during the whole of his life. In the same way,
I trust, that you will take comfort, and be delighted with yourselves,
on the discovery that you have been acting on the principles of
inductive and deductive philosophy during the same period. Probably
there is not one here who has not in the course of the day had occasion
to set in motion a complex train of reasoning, of the very same kind,
though differing of course in degree, as that which a scientific man
goes through in tracing the causes of natural phenomena.

A very trivial circumstance will serve to exemplify this. Suppose you
go into a fruiterer's shop, wanting an apple,--you take up one, and, on
biting it, you find it is sour; you look at it, and see that it is hard
and green. You take up another one, and that too is hard, green, and
sour. The shopman offers you a third; but, before biting it, you
examine it, and find that it is hard and green, and you immediately say
that you will not have it, as it must be sour, like those that you have
already tried.

Nothing can be more simple than that, you think; but if you will take
the trouble to analyze and trace out into its logical elements what has
been done by the mind, you will be greatly surprised. In the first
place, you have performed the operation of Induction. You found that,
in two experiences, hardness and greenness in apples go together with
sourness. It was so in the first case, and it was confirmed by the
second. True, it is a very small basis, but still it is enough to make
an induction from; you generalize the facts, and you expect to find
sourness in apples where you get hardness and greenness. You found