234 



Thoughts on Causality. 



the effect of a physical cause; and the mind now finds 

 two terms of intermediate causation interposed between 

 assumed first cause and ultimate phenomenon. The 

 opportunity presents itself, at this stage, for another observa- 

 tion which, in the development of science, becomes ex- 

 tremely significant. The recognized intermediate causes 

 of two separate phenomena appear, in many cases, as the 

 effects of the same cause. The number of assumed first 

 causes is therefore much less than the number of interme- 

 diate causes. 



With the further advance of reflection, it is ascertained 

 that the assumed first cause is again the effect of remoter 

 causation ; and so its aspect changes to that of an interme- 

 diate cause, and we find three terms interposed between phe- 

 nomenon and newly assumed first cause. At the same 

 time, it is observed that, in many cases, two of the previ- 

 ously assumed first causes are, in common, the effect of 

 one first cause, thus removed by three terms from pheno- 

 menon. 



Thus continues, through the instrumentality of researches 

 of the scientific kind, the process of interpolating new 

 terms of intermediate or secondary causation ; and parallel 

 with the retreat of primary causation into the ever dimmer 

 distance, is a diminution in the number of assumed first 

 causes. The tendency of lines of causation, or series of 

 effects, to converge, has been noted by every thinker. 

 This zone of secondary causes is the peculiar field of sci- 

 ence. 



Before proceeding further, one suggestive fact should 

 be conspicuously held up to view. The human mind all 

 along holds fast to its notion of primary causation. Dis- 

 appointed and deceived a hundred times, its faith in the 

 reality is not one whit abated. Reluctantly and sorrow- 

 fully driven from post to post, it moves on into the unex- 

 plored darkness, full of confidence that the object of its 

 trust will be found at last. Look, further, at the notion 



