, and the true if not the only progress of
historical criticism consists in the improvement of the instruments of
research.

Now first, as regards his conception of history, I have already pointed
out that it was to him essentially a search for causes, a problem to be
solved, not a picture to be painted, a scientific investigation into laws
and tendencies, not a mere romantic account of startling incident and
wondrous adventure. Thucydides, in the opening of his great work, had
sounded the first note of the scientific conception of history. 'The
absence of romance in my pages,' he says, 'will, I fear, detract somewhat
from its value, but I have written my work not to be the exploit of a
passing hour but as the possession of all time.' {203} Polybius follows
with words almost entirely similar. If, he says, we banish from history
the consideration of causes, methods and motives ([Greek]), and refuse to
consider how far the result of anything is its rational consequent, what
is left is a mere [Greek], not a [Greek], an oratorical essay which may
give pleasure for the moment, but which is entirely without any
scientific value for the explanation of the future. Elsewhere he says
that 'history robbed of the exposition of its causes and laws is a
profitless thing, though it may allure a fool.' And all through his
history the same point is put forward and exemplified in every fashion.

So far for the conception of history. Now for the groundwork. As
regards the character of the phenomena to be selected by the scientific
investigator, Aristotle had laid down the general formula that nature
should be studied in her normal manifestations. Polybius, true to his
character of applying explicitly the principles implicit in the work of
others, follows out the doctrine of Aristotle, and lays particular stress
on the rational and undisturbed character of the development of the Roman
constitution as affording special facilities for the discovery of the
laws of its progress. Political revolutions result from causes either
external or internal. The former are mere disturbing forces which lie
outside the sphere of scientific calculation. It is the latter which are
important for the establishing of principles and the elucidation of the
sequences of rational evolution.

He thus may be said to have anticipated one of the most important truths
of the modern methods of investigation: I mean that principle which lays
down that just a