ule" (p. 66). Thus "laws," which
were rightly said to be the statement of an order of facts in one
paragraph, are declared to be the facts themselves in the next.

We are next told that, though it may be customary and permissible to
use "law" in the sense of a statement of the order of facts, this is a
low use of the word; and, indeed, two pages farther on, the writer,
flatly contradicting himself, altogether denies its admissibility.

An observed order of facts, to be entitled to the rank of a
law, must be an order so constant and uniform as to indicate
necessity, and necessity can only arise out of the action
of some compelling force (p. 68).

This is undoubtedly one of the most singular propositions that I have
ever met with in a professedly scientific work, and its rarity is
embellished by another direct self-contradiction which it implies. For
on the preceding page (67), when the Duke of Argyll is speaking of the
laws of Kepler, which he admits to be laws, and which are types of
that which men of science understand by "laws," he says that they are
"simply and purely an order of facts." Moreover, he adds: "A very
large proportion of the laws of every science are laws of this kind
and in this sense."

If, according to the Duke of Argyll's admission, law is understood, in
this sense, thus widely and constantly by scientific authorities,
where is the justification for his unqualified assertion that such
statements of the observed order of facts are not "entitled to the
rank" of laws?

But let us examine the consequences of the really interesting
proposition I have just quoted. I presume that it is a law of nature
that "a straight line is the shortest distance between two points."
This law affirms the constant association of a certain fact of form
with a certain fact of dimension. Whether the notion of necessity
which attaches to it has an _a priori_, or an _a posteriori_ origin is
a question not relevant to the present discussion. But I would beg to
be informed, if it is necessary, where is the "compelling force" out
of which the necessity arises; and further, if it is not necessary,
whether it loses the character of a law of nature?

I take it to be the law of nature, based on unexceptionable evidence,
that the mass of matter remains unchanged, whatever chemical or other
modifications it may undergo. This law is one of the foundations of
chemistry. But it is by no means necessary. It is quit