COMPOSITION OF CAUSES. 213 



the weights of the elements which compose it. The weight either 

 of the elements or. of" the compound will vary, if they be carried fur- 

 ther from their centre of attraction, or brought nearer to it ; but what- 

 ever affects the one affects the other. They always remain precisely 

 equal. So again, the component parts of a vegetable or animal sub- 

 stance do not lose their mechanical and chemical properties as sepa- 

 rate agents, when, by a peculiar mode of juxtaposition, they, as an 

 aggregate whole, acquire physiological or vital properties in addition. 

 Those bodies continue, as before, to obey mechanical and chemical 

 laws, in so far as the operation of those laws is not counteracted by the 

 jiew laws which govern them as organized beings. When, in short, a 

 concurrence of causes takes place whicli calls into action new laws, 

 bearing no analogy to any that we can trace in the separate operation 

 of the causes, the new laws may supersede one portion of the previous 

 laws but coexist with ancither portion, and may even com})ound the 

 effect of thosfe previous laws with their own. 



Again, laws which were themselves generated in the second mode, 

 may generate others in the fir^t. Though there be laws which, like 

 those of chemistry and physiology, owe their existence to a breach of 

 the principle of Composition of Causes, it does not follow that these 

 peculiar, or as they might be termed, het.eropathic laws, are not capa- 

 ble of composition with one another. The causes which by one com- 

 bination have had their laws altered, may carry their new laws with 

 them unaltered into their ulterior combinations. And hence there is 

 no reason to despair of ultimately raising chemistry and physiology to 

 the condition of deductive sciences ; for though it is impossible to de- 

 duce all chemical and physiological truths from the laws or properties 

 of simple substances or elementary agents, they may probably be de- 

 ducible from laws whicli commence when these elementary agents are 

 brought together into some moderate number of not very complex 

 combinations. The Laws of Life will never be deducible from the 

 mere laws of the ingi-edients, but the prodigiously complex Facts of 

 Life may all be deducible from comparatively simple laws of life ; 

 which laws (depending indeed upon combinations, but upon compara- 

 tively simple combinations, of antecedents), may in more complex 

 circumstances be strictly comjiounded wjth one another, and with the 

 physical and chemical laws of the ingredients. The details of the 

 vital phenomena even now afford innumerable exemplifications of the 

 Composition of Causes; and in pi'oportion as these phenomena are 

 more ac(;urately studied, there aj)pears more and more reason to 

 believe tliat the same laws which operate in the simpler combinations 

 of circumstances do, in fact, continue to be obsei-ved in the more com- 

 plex. * This will be found c(jually true in the phenomena of mind ; 

 and even in social and political phenomena, the result of the laws of 

 mind. It is in the case of chemical phenomena that the least progress 



* For abundant illustrations of this remark, I may refer to the writings of Dr. W. B. 

 Carppnter, of Bristol, and ospecially his treatise on General Physiology, in which the high- 

 est generalizations which the science of life has yet reached, and the best modern concep- 

 tion of that science as a whole, are exhibited in a manner equally perspicuous and philo- 

 sophical. On the details of such a treatise the present writer would be an incompetent wit- 

 ness : these however have been sufficiently vouched for by some of the highest living 

 authorities ; while of the genuinely scientific spirit which pervades it, those ipay be per- 

 mitted to express an opinion, who v/ould not be entitled to ofler to a work on such a sub- 

 ject, any other praise. 



