ANCIENT SCIENCE. 19 



affirmed also that matter was governed by two distinct forces, which 

 respectively presided over combination and decomposition. These 

 he named love and hatred, and they appear to be identical with our 

 modern conceptions of 'attractive and repulsive forces. The introduction 

 of this notion of force, or the prominence Empedocles gave to it, marks 

 a new era in scientific speculation, for we have now the conception of 

 something acting upon matter, and this conception has pervaded sci- 

 entific thought more or less down to the present day. Not long ago 

 each class of phenomena was supposed to be controlled by a special 

 "force" the term used being not a mere figure of speech, but as the 

 name of an agent controlling matter, which was thought of as some- 

 thing passive or inert, merely moved by " force." For instance, it was 

 supposed the phenomena with which chemistry is conversant were ex- 

 plained by the supposition of the existence of a force called " chemical 

 affinity' 1 '' governing the combinations of matter. Later it was discovered 

 that "chemical affinity" was, after all, nothing but an expression for 

 a group of facts a mere trick of words. 



The notion of a world of 1 brute matter''' pushed or pulled hither 

 and thither by "forces," is derived from our own personal experiences. 

 A stone lies on the ground, and continues motionless until we kick it, 

 or push it, or lift it up. The effort we put forth in these actions is the 

 foundation of our idea of force, and as in general the stone moves not 

 without our efforts, we think of it as entirely passive. When, therefore, 

 we see the stone dropped from a height moving rapidly to the ground, 

 we say that a force is acting on the stone, we picture it to ourselves as 

 pulled towards the earth by the "force of gravitation? and as being 

 simply an inert mass upon which this force acts. But reflection shows us 

 that in reality the matter in the stone is as active in producing the result 

 as the matter of the earth, and that no ground whatever can be found for 

 declaring that there exists, apart from the earth and the stone, a tertium 

 quid, an agent called gravitation, acting upon the otherwise inert masses 

 of stone and earth. In reality "gravitation," like the phrase "chemical 

 affinity," is simply a sign we employ to express a certain class of phe- 

 nomena. These remarks will perhaps serve to indicate our tendency 

 to explain the phenomena which the world presents to us by notions 

 derived from our own consciousness. There is in the philosophy of 

 Empedocles a plain expression of this tendency, but in later philoso- 

 phers it became the acknowledged foundation of their system. Indeed, 

 the Grecian philosophy soon became so entirely subjective and concerned 

 itself so little about the facts of the external or object world, that the 

 study of these last came to be a distinct branch of intellectual pursuit, 

 and ancient science and philosophy finally parted company. Until 

 about the age of Plato, the philosopher and the scientific inquirer 

 were so commonly united in the same individual, that it would not be 

 easy to give an account of the development of scientific ideas without 

 referring to doctrines which perhaps more strictly belong to the domain 



