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.