20 PINAL CAUSES. 



vast importance, and extending over so wide a field as that 

 which lies before us, to examine with attention the nature 

 of those processes of reasoning, by which we are conducted 

 to the knowledge of the peculiar class of truths we are seek- 

 ing. Such a preliminary inquiry is the more necessary, in- 

 asmuch as the investigation of these truths is beset wdth 

 many formidable difficulties and liable to various sources of 

 fallacy, which are not met with in the study of other depart- 

 ments of philosophy. 



The proper objects of all human knowledge are the rela- 

 tions that exist among the phenomena of which the mind 

 has cognizance. The phenomena of the universe may be 

 viewed as connected with one another either by the relation 

 of cause and effect, or by that of means and end; and, ac- 

 cordingly, these two classes of relations give rise to different 

 kinds of knowledge, each of which requires to be inves- 

 tigated in a peculiar mode and by a different process of rea- 

 soning. The foundation of both these kinds of knowledge 

 is, indeed, the same; namely, the constant uniformity which 

 takes place in the succession of events, and which, when 

 traced in particular classes of phenomena, constitutes what 

 we metaphorically call the Laws of Nature. It is the pro- 

 vince of philosophy, strictly so called, to discover the cir- 

 cumstances or laws which regulate this uniformity, and to 

 arrange the observed changes according to their invariable 

 antecedents, or causes: the unknown links by which these 

 causes are connected with their respective consequents, or 

 effects, being denominated the powers of Nature. With 

 reference to phenom.ena which are purely mechanical, that 

 is, to changes which consist in the sensible motions of ma- 

 terial bodies, these powers are denominated /orce.s; and the 

 intensities, the operations, and the characters of these forces 

 admit of exact definition, according to the qualities of the 

 corresponding efiects they produce. It is by pursuing the 

 method of philosophical induction, so well explained by Ba- 

 con, that the physical sciences, which the misdirected efTorts 

 of former ages had failed to advance, have, within the last 



