XLIII.] CLASSIFICATION OF THE SCIENCES. 201 



an encyclopaedia of the sciences that each separate science 

 can be fully treated of without any anticipatory reference to 

 those which are to follow it. For instance : — The chemical 

 group of sciences, as I shall have to show, conies after the 

 dynamical group, and is dependent thereon: electricity 

 belongs on the whole to the dynamical group, yet the facts 

 of electro-chemistry, as already remarked, belong as much 

 to chemical as to electrical science, so that they cannot be 

 explained or even stated without taking some of the facts 

 of chemistry as known. The best arrangement of the 

 sciences, however, is that in which the smallest number 

 of such anticipatory references is needed ; and we can 

 approach much nearer to such an arrangement than could 

 have been thought possible. 



The value of this aiTangement is greatly increased by The order 

 the fact that it places the simplest and most general s-Jpie\,,| 

 subjects first, and the more complex and special ones general 

 after these ; for the more complex and special subjects complex 

 depend on the simpler and more general ones, but the ^JJ^^.^j_ 

 simple and general do not depend on the complex and 

 special. Thus the facts of biology are more complex 

 than those of chemistry ; and they are also more special ; 

 for all substances have chemical properties, but only some 

 substances are vitalized, or capable of vitalization. It is 

 necessary to observe that, in speaking of the simplicity 

 and generality of any set of scientific facts, I speak of the 

 subject-matter of the science only, and not of its pro- 

 cesses. The processes of mathematics are more intricate 

 than those of chemistry ; but the subject-matter of mathe- 

 matics is perfectly simple and absolutely general, consisting 

 in the properties of space and time : while the subject- 

 matters of chemistry are neither general nor simple ; on 

 the contrary, they are special, for every substance has 

 its own peculiar properties ; and they are so complex and 

 varied that no complete enumeration is yet possible of 

 the properties of any substance whatever. 



What I have said on the subject of the classification Summary, 

 of the sciences may be summed up in this formula : — 



