An introduction to mathematics, by A. N. Whitehead.

DIFFERENTIAL CALCULUS 219
tician and a philosopher, and each of them
in his own department of thought was one of
the greatest men of genius that the world
has known. The joint invention was the
occasion of an unfortunate and not very
creditable dispute. Newton was using the
methods of Fluxions, as he called the subject, in 1666, and employed it in the composition of his Principia, although in the work
as printed any special algebraic notation is
avoided. But he did not print a direct statement of his method till 1693. Leibniz published his first statement in 1684. He was
accused by Newton's friends of having got
it from a MS. by Newton, which he had been
shown privately. Leibniz also accused Newton of having plagiarized from him. There
is now not very much doubt but that both
should have the credit of being independent
discoverers. The subject had arrived at a
stage in which it was ripe for discovery, and
there is nothing surprising in the fact that
two such able men should have independently hit upon it.
These joint discoveries are quite common
in science. Discoveries are not in general
made before they have been led up to by
the previous trend of thought, and by that
time many minds are in hot pursuit of the
important idea. If we merely keep to discoveries in which Englishmen are concerned,