fore a common influence. Climate is such a
fact, or the discovery of America, or the invention of printing, or the
rates of wages and prices. All nonconformists are influenced by their
memory of certain facts of which very few churchmen are aware, and all
Irishmen by facts which most Englishmen try to forget. The student of
politics must therefore read history, and particularly the history of
those events and habits of thought in the immediate past which are
likely to influence the generation in which he will work. But he must
constantly be on his guard against the expectation that his reading will
give him much power of accurate forecast. Where history shows him that
such and such an experiment has succeeded or failed he must always
attempt to ascertain how far success or failure was due to facts of the
human type, which he may assume to have persisted into his own time, and
how far to facts of environment. When he can show that failure was due
to the ignoring of some fact of the type and can state definitely what
that fact is, he will be able to attach a real meaning to the repeated
and unheeded maxims by which the elder members of any generation warn
the younger that their ideas are 'against human nature.' But if it is
possible that the cause was one of mental environment, that is to say, of
habit or tradition, or memory, he should be constantly on his guard
against generalisations about national or racial 'character.'

One of the most fertile sources of error in modern political thinking
consists, indeed, in the ascription to collective habit of that
comparative permanence which only belongs to biological inheritance. A
whole science can be based upon easy generalisations about Celts and
Teutons, or about East and West, and the facts from which the
generalisations are drawn may all disappear in a generation. National
habits used to change slowly in the past, because new methods of life
were seldom invented and only gradually introduced, and because the
means of communicating ideas between man and man or nation and nation
were extremely imperfect; so that a true statement about a national
habit might, and probably would, remain true for centuries. But now an
invention which may produce profound changes in social or industrial
life is as likely to be taken up with enthusiasm in some country on the
other side of the globe as in the place of its origin. A statesman who
has anything important to say says it to an audience