figure, and by the still more general theory of Natural Selection, if
facts could be adduced to show that the toad's appearance does really
deter its enemies. Such an hypothesis resembles an Empirical Law in its
need of derivation (chap. xix. Sec.Sec. 1, 2). If underivable from, or
irreconcilable with, known laws, it is a mere conjecture or prejudice.
The absolute leviation of phlogiston, in contrast with the gravitation
of all other forms of matter, discredited that supposed agent. That
Macpherson should have found the Ossianic poems extant in the Gaelic
memory, was contrary to the nature of oral tradition; except where
tradition is organised, as it was for ages among the Brahmins. The
suggestion that xanthochroid Aryans were "bleached" by exposure during
the glacial period, does not agree with Wallace's doctrine concerning
the coloration of Arctic animals. That our forefathers being predatory,
like bears, white variations amongst them were then selected by the
advantage of concealment, is a more plausible hypothesis.

Although, then, the consilience of Inductions or Hypotheses is not a
sufficient proof of their truth, it is still a condition of it;
nonconsilience is a suspicious circumstance, and resilience (so to
speak), or mutual repugnance, is fatal to one or all.

Sec. 4. We have now seen that a scientific hypothesis, to deserve the name,
must be verifiable and therefore definite; and that to establish itself
as a true theory, it must present some symptom of reality, and be
adequate and exclusive and in harmony with the system of experience.
Thus guarded, hypotheses seem harmless enough; but some people have a
strong prejudice against them, as against a tribe of savages without
government, or laws, or any decent regard for vested interests. It is
well known, too, that Bacon and Newton disparaged them. But Bacon, in
his examples of an investigation according to his own method, is
obliged, after a preliminary classification of facts, to resort to an
hypothesis, calling it _permissio intellectus_, _interpretatio inchoata_
or _vindemiatio prima_. And Newton when he said _hypotheses non fingo_,
meant that he did not deal in fictions, or lay stress upon supposed
forces (such as 'attraction'), that add nothing to the law of the facts.
Hypotheses are essential aids to discovery: speaking generally,
deliberate investigation depends wholly upon the use of them.

It is true that we may sometimes observe a train of events t