46 HISTORY OF INDUCTIVE SCIENCES. 



uotion ; — preserves as well as expresses a truth ;— and, like a medal of 

 gold, is a treasure as well as a token. We shall frequently have to 

 notice the manner in which great discoveries thus stamp their impress 

 ii] m m the terms of a science ; and, like great political revolutions, are re- 

 corded by the change of the current coin which has accompanied them. 



Generalization.— The great changes which thus take place in the 

 history of science, the revolutions of the intellectual world, have, as a 

 usual and. leading character, this, that they are steps of generalization ; 

 transitions from particular truths to others of a wider extent, in which 

 the former are included. This progress of knowledge, from individual 

 facts to universal laws, — from particular propositions to general ones, 

 — and from these to others still more general, with reference to which 

 the former generalizations are particular, — is so far familiar to men's 

 minds, that, without here entering into further explanation, its nature 

 will be understood sufficiently to prepare the reader to recognize the 

 exemplifications of such a process, which he will find at every step of 

 our advance. 



Inductive .Epochs; Preludes; Sequels. — In our history, it is the 

 progress of knowledge only which we have to attend to. This is the 

 main action of our drama ; and all the events which do not bear upon 

 this, though they may relate to the cultivation and the cultivators of 

 philosophy, are not a necessary part of our theme. Our narrative will 

 therefore consist mainly of successive steps of generalization, such as 

 have just been mentioned. But among these, we shall find some of 

 eminent and decisive importance, which have more peculiarly influ- 

 enced the fortunes of physical philosophy, and to which we may con- 

 sider the rest as subordinate and auxiliary. These primary movements, 

 when the Inductive process, by which science is formed, has been exer- 

 cised in a more energetic and powerful manner, may be distinguished 

 as the Inductive Ejwchs of scientific history ; and they deserve our 

 more express and pointed notice. They are, for the most part, marked 

 by the great discoveries and the great philosophical names which all 

 civilized nations have agreed in admiring. But, when we examine 

 more clearly the history of such discoveries, we find that these epochs 

 have not occurred suddenly and without preparation. They have 

 been preceded by a period, which we may call their Prelude, during 

 which the ideas and facts on which they turned were called into action ; 

 — were gradually evolved into clearness and connection, permanency 

 and certainty ; till at last the discovery which marks the epoch, seized 

 and fixed forever the truth which had till then been obscurelv and 



