Brahe's accurate observations; and it was only after some progress
in physical and chemical science that the improved instruments with
which those observations were made, became possible. The heliocentric
theory of the solar system had to wait until the invention of the
telescope before it could be finally established. Nay, even the grand
discovery of all--the law of gravitation--depended for its proof upon an
operation of physical science, the measurement of a degree on the
Earth's surface. So completely indeed did it thus depend, that Newton
_had actually abandoned his hypothesis_ because the length of a degree,
as then stated, brought out wrong results; and it was only after
Picart's more exact measurement was published, that he returned to his
calculations and proved his great generalisation. Now this constant
intercommunion, which, for brevity's sake, we have illustrated in the
case of one science only, has been taking place with all the sciences.
Throughout the whole course of their evolution there has been a
continuous _consensus_ of the sciences--a _consensus_ exhibiting a
general correspondence with the _consensus_ of faculties in each phase
of mental development; the one being an objective registry of the
subjective state of the other.

From our present point of view, then, it becomes obvious that the
conception of a _serial_ arrangement of the sciences is a vicious one.
It is not simply that the schemes we have examined are untenable; but it
is that the sciences cannot be rightly placed in any linear order
whatever. It is not simply that, as M. Comte admits, a classification
"will always involve something, if not arbitrary, at least artificial;"
it is not, as he would have us believe, that, neglecting minor
imperfections a classification may be substantially true; but it is that
any grouping of the sciences in a succession gives a radically erroneous
idea of their genesis and their dependencies. There is no "one
_rational_ order among a host of possible systems." There is no "true
_filiation_ of the sciences." The whole hypothesis is fundamentally
false. Indeed, it needs but a glance at its origin to see at once how
baseless it is. Why a _series_? What reason have we to suppose that the
sciences admit of a _linear_ arrangement? Where is our warrant for
assuming that there is some _succession_ in which they can be placed?
There is no reason; no warrant. Whence then has arisen the supposition?
To use M. Comte's