a uniformity of
Coexistence. But the distinction is really immaterial to Logic.
What Logic is concerned with is the observation of the facts and the
validity of any inference based on them: and in these respects it
makes no difference whether the uniformity that we observe and found
upon is one of Sequence or of Coexistence.

It was exclusively to such inferences, inferences from observed facts
of repeated coincidence, that Mill confined himself in his theory of
Induction, though not in his exposition of the methods. These are the
inferences for which we must postulate what he calls the Uniformity
of Nature. Every induction, he says, following Whately, may be thrown
into the form of a Syllogism, in which the principle of the Uniformity
of Nature is the Major Premiss, standing to the inference in the
relation in which the Major Premiss of a Syllogism stands to the
conclusion. If we express this abstractly denominated principle in
propositional form, and take it in connexion with Mill's other saying
that the course of Nature is not a uniformity but uniformities, we
shall find, I think, that this postulated Major Premiss amounts to an
assumption that the observed Uniformities of Nature continue. Mill's
Inductive Syllogism thus made explicit would be something like this:--

All the observed uniformities of Nature continue.
That all men have died is an observed uniformity.
_Therefore_, it continues; _i.e._, all men will die and did die
before the beginning of record.

There is no doubt that this is a perfectly sound postulate. Like all
ultimate postulates it is indemonstrable; Mill's derivation of it
from Experience did not amount to a demonstration. It is simply an
assumption on which we act. If any man cares to deny it, there is
no argument that we can turn against him. We can only convict him of
practical inconsistency, by showing that he acts upon this assumption
himself every minute of his waking day. If we do not believe in the
continuance of observed uniformities, why do we turn our eyes to the
window expecting to find it in its accustomed order of place? Why do
we not look for it in another wall? Why do we dip our pens in ink,
and expect the application of them to white paper to be followed by a
black mark?

The principle is sound, but is it our only postulate in inference to
the unobserved, and does the continuance of empirical laws represent
all that Science assumes in its inferences? Mill was not sati