The discussion with Locke was a failure: Locke would not play, and the book
in which the whole controversy was to be systematized never appeared. The
discussion with Bayle, on the other hand, was a model of what a discussion
should be. Bayle played up tirelessly, and was never embarrassingly
profound; he provided just the sort of objections most useful for drawing
forth illuminating expositions; he was as good as a fictitious character in
a philosophical dialogue. And the book in which the controversy was
systematized duly appeared with great éclat.

Here is the history of the controversy. In 1695 Leibniz was forty-nine
years old. He had just emerged from a period of close employment under his
prince's commands, and he thought fit to try his metaphysical principles
upon the polite world and see what would come of it. He therefore published
an article in the _Journal des Savants_ under the title: 'New System of
Nature and of the Communication of Substances, as well as of the Union
between Soul and Body'. In the same year Foucher published an article in
the _Journal_ controverting Leibniz; and in the next year Leibniz replied
with an 'Explanation'. A second explanation in the same year appeared in
Basnage's _Histoire des Ouvrages des Savants_, in answer to reflexions by
the editor. M. Pierre Bayle had all these articles before him when he
inserted a note on Leibniz's doctrine in his article on 'Rorarius', in the
first edition of his _Historical and Critical Dictionary_. The point of
connexion between Rorarius and Leibniz was no more than this, that both
held views about the souls of beasts.

Pierre Bayle was the son of a Calvinist pastor, early converted to
Catholicism, but recovered to his old faith after a short time. He held
academic employments in Switzerland and Holland; he promoted and edited the
_Nouvelles de la République des Lettres_, and he produced that
extraordinary work the _Historical and Critical Dictionary._ The notices it