tion is more important to them than concealment (as with
the musk-sheep)'. The same end of universal statement may be gained by
including the conditions on which the phenomenon depends, thus: 'All
arctic animals to whom concealment is of the utmost utility are white.'

When statistics are obtainable, it is proper to convert an approximate
generalisation into a proportional statement of the fact, thus: instead
of 'Most attacks of plague are fatal', we might find that in a certain
country 70 per cent. were so. Then, if we found that in another country
the percentage of deaths was 60, in another 40, we might discover, in
the different conditions of these countries, a clue to the high rate of
mortality from this disease. Even if the proportion of cases in which
two facts are connected does not amount to 'Most,' yet, if any definite
percentage is obtainable, the proposition has a higher scientific value
than a vague 'Some': as if we know that 2 per cent. of the deaths in
England are due to suicide, this may be compared with the rates of
suicide in other countries; from which perhaps inferences may be drawn
as to the causes of suicide.

In one department of life, namely, Politics, there is a special
advantage in true approximate generalisations amounting to 'Most cases.'
The citizens of any State are so various in character, enlightenment,
and conditions of life, that we can expect to find few propositions
universally true of them: so that propositions true of the majority must
be trusted as the bases of legislation. If most men are deterred from
crime by fear of punishment; if most men will idle if they can obtain
support without industry; if most jurymen will refuse to convict of a
crime for which the prescribed penalties seem to them too severe; these
are most useful truths, though there should be numerous exceptions to
them all.

Sec. 3. Secondary Laws can only be trusted in 'Adjacent Cases'; that is,
where the circumstances are similar to those in which the laws are known
to be true.

A Derivative Law will be true wherever the forces concerned exist in the
combinations upon which the law depends, if there are no counteracting
conditions. That water can be pumped to about 33 feet at the sea-level,
is a derivative law on this planet: is it true in Mars? That depends on
whether there are in Mars bodies of a liquid similar to our water;
whether there is an atmosphere there, and how great its pressure is;
which will vary