balance and finely graduated weights. It is not that
the action of the scales in the one case, and the balance in the other,
differ in the principles of their construction or manner of working; but
the beam of one is set on an infinitely finer axis than the other, and
of course turns by the addition of a much smaller weight.

You will understand this better, perhaps, if I give you some familiar
example. You have all heard it repeated, I dare say, that men of science
work by means of induction and deduction, and that by the help of these
operations, they, in a sort of sense, wring from Nature certain other
things, which are called natural laws, and causes, and that out of
these, by some cunning skill of their own, they build up hypotheses and
theories. And it is imagined by many, that the operations of the common
mind can be by no means compared with these processes, and that they
have to be acquired by a sort of special apprenticeship to the craft.
To hear all these large words, you would think that the mind of a man of
science must be constituted differently from that of his fellow men; but
if you will not be frightened by terms, you will discover that you are
quite wrong, and that all these terrible apparatus [87] are being used
by yourselves every day and every hour of your lives.

There is a well-known incident in one of Moliere's plays,[88] 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