were not separable from the intellectual conditions
under which they lived. Their genius was their own; and they were not
the rash and hasty generalizers which, since the days of Bacon, we
have been apt to suppose them. The thoughts of men widened to receive
experience; at first they seemed to know all things as in a dream: after
a while they look at them closely and hold them in their hands. They
begin to arrange them in classes and to connect causes with effects.
General notions are necessary to the apprehension of particular facts,
the metaphysical to the physical. Before men can observe the world, they
must be able to conceive it.

To do justice to the subject, we should consider the physical philosophy
of the ancients as a whole; we should remember, (1) that the nebular
theory was the received belief of several of the early physicists; (2)
that the development of animals out of fishes who came to land, and of
man out of the animals, was held by Anaximander in the sixth century
before Christ (Plut. Symp. Quaest; Plac. Phil.); (3) that even by
Philolaus and the early Pythagoreans, the earth was held to be a body
like the other stars revolving in space around the sun or a central
fire; (4) that the beginnings of chemistry are discernible in the
'similar particles' of Anaxagoras. Also they knew or thought (5) that
there was a sex in plants as well as in animals; (6) they were aware
that musical notes depended on the relative length or tension of the
strings from which they were emitted, and were measured by ratios
of number; (7) that mathematical laws pervaded the world; and even
qualitative differences were supposed to have their origin in number and
figure; (8) the annihilation of matter was denied by several of them,
and the seeming disappearance of it held to be a transformation only.
For, although one of these discoveries might have been supposed to be
a happy guess, taken together they seem to imply a great advance and
almost maturity of natural knowledge.

We should also remember, when we attribute to the ancients hasty
generalizations and delusions of language, that physical philosophy and
metaphysical too have been guilty of similar fallacies in quite recent
times. We by no means distinguish clearly between mind and body, between
ideas and facts. Have not many discussions arisen about the Atomic
theory in which a point has been confused with a material atom? Have not
the natures of things been explained by im