“Il faut distinguer par rapport a tous les ordres des phenomenes, deux genres de sciences naturelles; les unes abstraites, generales, ont pour objet la decouverte des lois qui regissent les diverses classes de phenomenes, en considerant tous les cas qu’on peut concevoir; les autres concretes, particulieres, descriptives, et qu’on designe quelquefois sous le nom des sciences naturelles proprement dites, consistent dans l’application de ces lois a l’histoire effective des differents etres existants."[23]

The “abstract” sciences are subsequently said to be mathematics, astronomy, physics, chemistry, physiology, and social physics—­the titles of the two latter being subsequently changed to biology and sociology.  M. Comte exemplifies the distinction between his abstract and his concrete sciences as follows:—­

“On pourra d’abord l’apercevoir tres-nettement en comparant, d’une part, la physiologie generale, et d’une autre part la zoologie et la botanique proprement dites.  Ce sont evidemment, en effet, deux travaux d’un caractere fort distinct, que d’etudier, en general, les lois de la vie, ou de determiner le mode d’existence de chaque corps vivant, en particulier. Cette seconde etude, en outre, est necessairememt fondee sur la premiere.”—­P. 57.

All the unreality and mere bookishness of M. Comte’s knowledge of physical science comes out in the passage I have italicised.  “The special study of living beings is based upon a general study of the laws of life!” What little I know about the matter leads me to think, that, if M. Comte had possessed the slightest practical acquaintance with biological science, he would have turned his phraseology upside down, and have perceived that we can have no knowledge of the general laws of life, except that which is based upon the study of particular living beings.

The illustration is surely unluckily chosen; but the language in which these so-called abstract sciences are defined seems to me to be still more open to criticism.  With what propriety can astronomy, or physics, or chemistry, or biology, be said to occupy themselves with the consideration of “all conceivable cases” which fall within their respective provinces?  Does the astronomer occupy himself with any other system of the universe than that which is visible to him?  Does he speculate upon the possible movements of bodies which may attract one another in the inverse proportion of the cube of their distances, say?  Does biology, whether “abstract” or “concrete,” occupy itself with any other form of life than those which exist, or have existed?  And, if the abstract sciences embrace all conceivable cases of the operation of the laws with which they are concerned, would not they, necessarily, embrace the subjects of the concrete sciences, which, inasmuch as they exist, must needs be conceivable?  In fact, no such distinction as that which M. Comte draws is tenable.  The first stage of his classification breaks by its own weight.