Even if theory had not stood in his way, Fontenelle was the last man who was likely to dream dreams of social improvement.  He was temperamentally an Epicurean, of the same refined stamp as Epicurus himself, and he enjoyed throughout his long life—­he lived to the age of a hundred—­the tranquillity which was the true Epicurean ideal.  He was never troubled by domestic cares, and his own modest ambition was satisfied when, at the age of forty, he was appointed permanent Secretary of the Academy of Sciences.  He was not the man to let his mind dwell on the woes and evils of the world; and the follies and perversities which cause them interested him only so far as they provided material for his wit.

It remains, however, noteworthy that the author of the theory of the progress of knowledge, which was afterwards to expand into a general theory of human Progress, would not have allowed that this extension was legitimate; though it was through this extension that Fontenelle’s idea acquired human value and interest and became a force in the world.

9.

Fontenelle did a good deal more than formulate the idea.  He reinforced it by showing that the prospect of a steady and rapid increase of knowledge in the future was certified.

The postulate of the immutability of the laws of nature, which has been the indispensable basis for the advance of modern science, is fundamental with Descartes.  But Descartes did not explicitly insist on it, and it was Fontenelle, perhaps more than any one else, who made it current coin.  That was a service performed by the disciple; but he seems to have been original in introducing the fruitful idea of the sciences as confederate and intimately interconnected [Footnote:  Roger Bacon, as we saw, had a glimpse of this principle.]; not forming a number of isolated domains, as hitherto, but constituting a system in which the advance of one will contribute to the advance of the others.  He exposed with masterly ability the reciprocal relations of physics and mathematics.  No man of his day had a more comprehensive view of all the sciences, though he made no original contributions to any.  His curiosity was universal, and as Secretary of the Academy he was obliged, according to his own high standard of his duty, to keep abreast of all that was being done in every branch of knowledge.  That was possible then; it would be impossible now.

In the famous series of obituary discourses which he delivered on savants who were members of the Academy, Fontenelle probably thought that he was contributing to the realisation of this ideal of “solidarity,” for they amounted to a chronicle of scientific progress in every department.  They are free from technicalities and extraordinarily lucid, and they appealed not only to men of science, but to those of the educated public who possessed some scientific curiosity.  This brings us to another important role of Fontenelle—­ the role of interpreter of the world of science to the world outside.  It is closely related to our subject.