had prepared the way; progress was established for the past and
present. But the theory of the progress of knowledge includes and
acquires its value by including the indefinite future. This step was
taken by Fontenelle. The idea had been almost excluded by Bacon's
misleading metaphor of old age, which Fontenelle expressly rejects.
Man will have no old age; his intellect will never degenerate; and
"the sound views of intellectual men in successive generations will
continually add up."

But progress must not only be conceived as extending indefinitely
into the future; it must also be conceived as necessary and certain.
This is the second essential feature of the theory. The theory would
have little value or significance, if the prospect of progress in
the future depended on chance or the unpredictable discretion of an
external will. Fontenelle asserts implicitly the certainty of
progress when he declares that the discoveries and improvements of
the modern age would have been made by the ancients if they
exchanged places with the moderns; for this amounts to saying that
science will progress and knowledge increase independently of
particular individuals. If Descartes had not been born, some one
else would have done his work; and there could have been no
Descartes before the seventeenth century. For, as he says in a later
work, [Footnote: Preface des elemens de la geometrie de l'infini
(OEuvres, x. p. 40, ed. 1790).] "there is an order which regulates
our progress. Every science develops after a certain number of
preceding sciences have developed, and only then; it has to await
its turn to burst its shell."

Fontenelle, then, was the first to formulate the idea of the
progress, of knowledge, as a complete doctrine. At the moment the