38 DEFINITIONS OF LIFE. 



What is Life? Were such a question proposed, we should 

 be tempted to answer, what is not Life that really is? 

 Our reason convinces us that the quantities of things, 

 taken abstractedly as quantity, exist only in the relations 

 they bear to the percipient ; in plainer words, they exist 



common character of a whole class in the nomenclature of botany would 

 enable a person to understand all, or any one of the plants contained in that 

 class. But if, on the other hand, the machine in question were such as no 

 man was a stranger to, if even the supposed peculiarity, either by its effects, 

 or by the construction of that portion of the works which produced them, were 

 equally well known to all men, in this case we can conceive no use at all of such 

 a definition ; for at the best it could only be admitted as a definition for the 

 purposes of nomenclature, which never adds to knowledge, although it may 

 often facilitate its communication. But in this instance it would be nomen- 

 clature misplaced, and without an object. Such appears to me to be the case 

 with all those definitions which place the essence of Life in nutrition, con- 

 tractility, &c. As the second instance, I will take the inventor and maker 

 of the machine himself, who knows its moving power, or perhaps himself con- 

 stitutes it, who is, as it were, the soul of the work, and in whose mind all its 

 parts, with all their bearings and relations, had pre-existed long before the 

 machine itself had been put together. In him therefore there would reside, 

 what it would be presumption to attempt to acquire, or to pretend to com- 

 municate, the most perfect insight not only of the machine itself, and of all 

 its various operations, but of its ultimate principle and its essential causes. 

 The mysterious ground, the efficient causes of vitality, and whether different 

 lives differ absolutely or only in degree, He alone can know who not only said, 

 " Let the earth bring forth the living creature, the beast of the earth after his 

 kind, and it was so;" but who said, "Let us make man in our image, who 

 himself breathed into his nostrils the breath of Life, and man became a living 

 soul." 



The third case which I would apply to my own attempt would be that of 

 the inquirer, who, presuming to know nothing of the power that moves the 

 whole machine, takes those parts of it which are presented to his view, seeks 

 to reduce its various movements to as few and simple laws of motion as 

 possible, and out of their separate and conjoint action proceeds to explain and 

 appropriate the structure and relative positions of the works. In obedience 

 to the canon, " Principia non esse multiplicanda prseter summam necessitatem 

 cui suffragamur non ideo quia causalem in mundo unitatem vel ratione vel ex- 

 perientia perspicianius, sed illam ipsam indagamus impulsu intellectus, qui 

 tantundem sibi in explicatione phaenomenorum profecisse videtur quantum ab 

 eodem principio ad plurima rationata descendere ipsi concessum est." 



