Cartesian enunciation of natural law. And his work contributed to the
service, not of the doctrine of the past, but of the doctrine of the
future.

For he attempted to extend the Cartesian theory to social facts. He laid
down that political, like physical, phenomena are subject to general
laws. He had already conceived this, his most striking and important
idea, when he wrote the Considerations on the Greatness and Decadence of
the Romans (1734), in which he attempted to apply it:

It is not Fortune who governs the world, as we see from the history of
the Romans. There are general causes, moral or physical, which operate
in every monarchy, raise it, maintain it, or overthrow it; all that
occurs is subject to these causes; and if a particular cause, like the
accidental result of a battle, has ruined a state, there was a general
cause which made the downfall of this state ensue from a single battle.
In a word, the principal movement (l'allure principale) draws with it
all the particular occurrences.

But if this excludes Fortune it also dispenses with Providence, design,
and final causes; and one of the effects of the Considerations which
Montesquieu cannot have overlooked was to discredit Bossuet's treatment
of history.

The Esprit des lois appeared fourteen years later. Among books which
have exercised a considerable influence on thought few are more
disappointing to a modern reader. The author had not the gift of what
might be called logical architecture, and his work produces the effect
of a collection of ideas which he was unable to co-ordinate in the
clarity of a system. A new principle, the operation of general causes,
is enthroned; but, beyond the obvious distinction of physical and moral,
they are not classified. We have no guarantee that the moral causes are
fully enumerated, and those which are original are not distinguished
from those which are derived. The general cause which Montesquieu
impresses most clearly on the reader's mind is that of physical
environment--geography and climate.

The influence of climate on civilisation was not a new idea. In modern
times, as we have seen, it was noticed by Bodin and recognised by
Fontenelle. The Abbe de Saint-Pierre applied it to explain the origin of
the Mohammedan religion, and the Abbe Du Bos in his Reflexions on Poetry
and Painting maintained that climate helps to determine the epochs
of art and science. Chardin in his Travels, a book which Montesquieu
studi