question), and that is, the method by which, from the relations of
certain phenomena, we prove that some stand in the position of causes
towards the others.

I want to put the case clearly before you, and I will therefore show you
what I mean by another familiar example. I will suppose that one of
you, on coming down in the morning to the parlour of your house, finds
that a tea-pot and some spoons which had been left in the room on the
previous evening are gone,--the window is open, and you observe the mark
of a dirty hand on the window-frame, and perhaps, in addition to that,
you notice the impress of a hob-nailed shoe on the gravel outside. All
these phenomena have struck your attention instantly, and before two
minutes have passed you say, "Oh, somebody has broken open the window,
entered the room, and run off with the spoons and the tea-pot!" That
speech is out of your mouth in a moment. And you will probably add, "I
know there has; I am quite sure of it!" You mean to say exactly what
you know; but in reality what you have said has been the expression of
what is, in all essential particulars, an Hypothesis. You do not 'know'
it at all; it is nothing but an hypothesis rapidly framed in your own
mind! And it is an hypothesis founded on a long train of inductions
and deductions.

What are those inductions and deductions, and how have you got at this
hypothesis? You have observed, in the first place, that the window is
open; but by a train of reasoning involving many Inductions and
Deductions, you have probably arrived long before at the General
Law--and a very good one it is--that windows do not open of themselves;
and you therefore conclude that something has opened the window. A
second general law that you have arrived at in the same way is, that
tea-pots and spoons do not go out of a window spontaneously, and you