y the fifth, and sociology the sixth and last place in
the series. M. Comte's arguments in favour of this classification are
first--

"Sa conformite essentielle avec la co-ordination, en quelque sorte
spontanee, qui se trouve en effet implicitement admise par les
savants livres a l'etude des diverse branches de la philosophie
naturelle."

But I absolutely deny the existence of this conformity. If there is one
thing clear about the progress of modern science, it is the tendency to
reduce all scientific problems, except those which are purely
mathematical, to questions of molecular physics--that is to, say, to the
attractions, repulsions, motions, and co-ordination of the ultimate
particles of matter. Social phaenomena are the result of the interaction
of the components of society, or men, with one another and the
surrounding universe. But, in the language of physical science, which,
by the nature of the case, is materialistic, the actions of men, so far
as they are recognisable by science, are the results of molecular
changes in the matter of which they are composed; and, in the long run,
these must come into the hands of the physicist. _A fortiori_, the
phaenomena of biology and of chemistry are, in their ultimate analysis,
questions of molecular physics. Indeed, the fact is acknowledged by all
chemists and biologists who look beyond their immediate occupations. And
it is to be observed, that the phaenomena of biology are as directly and
immediately connected with molecular physics as are those of chemistry.
Molar physics, chemistry, and biology are not three successive steps in
the ladder of knowledge, as M. Comte would have us believe, but three
branches springing from the common stem of molecular physics.

As to astronomy, I am at a loss to understand how any one who will give
a moment's attention to the nature of the science can fail to see that
it consists of two parts: first, of a description of the phaenomena,
which is as much entitled as descriptive zoology, or botany, is, to the
name of natural history; and, secondly, of an explanation of the
phaenomena, furnished by the laws of a force--gravitation--the study of
which is as much a part of physics, as is that of heat, or electricity.
It would be just as reasonable to make the study of the heat of the sun
a science preliminary to the rest of thermotics, as to place the study
of the attraction of the bodies, which compose the universe in gen