it were
discovered the obscure laws of nature, is no explanation of the
inductive process, but is itself an induction (not, as some think, an
intuitive principle which experience _verifies_ only), and is arrived at
after many separate phenomena have been first observed to take place
according to general laws. It does not, then, _prove_ all other
inductions. But it is a _condition_ of their proof. For any induction
can be turned into a syllogism by supplying a major premiss, viz. What
is true of this, that, &c. is true of the whole class; and the process
by which we arrive at this immediate major may be itself represented by
another syllogism or train of syllogisms, the major of the ultimate
syllogism, and which therefore is the warrant for the immediate major,
being this axiom, viz. that there is uniformity, at all events, in the
class of phenomena to which the induction relates, and a uniformity
which, if not foreknown, may now be known.

But though the course of nature is uniform, it is also infinitely
various. Hence there is no certainty in the induction in use with the
ancients, and all non-scientific men, and which Bacon attacked, viz.
'Inductio per enumerationem simplicem, ubi non reperitur instantia
contradictoria'--_unless_, as in a few cases, we must have known of the
contradictory instances if existing. The scientific theory of induction
alone can show why a general law of nature may sometimes, as when the
chemist first discovers the existence and properties of a before unknown
substance, be inferred from a single instance, and sometimes (e.g. the
blackness of all crows) not from a million.

CHAPTER IV.

LAWS OF NATURE.

The uniformity of the course of nature is a complex fact made up of all
the separate uniformities in respect to single phenomena. Each of these
separate uniformities, if it be not a mere case of and result from
others, is a law of nature; for, though _law_ is used for any general
proposition expressing a uniformity, _law of nature_ is restricted to
cases where it has been thought that a separate act of creative will is
necessary to account for the uniformity. Laws of nature, in the
aggregate, are the fewest general propositions from which all the
uniformities in the universe might be deducted. Science is ever tending
to resolve one law into a higher. Thus, Kepler's three propositions,
since having been resolved by Newton into, and shown to be cases of the
three laws of motion, may