An Introduction to a Biology 



about life. It also continued to be satisfying for 

 another reason. Man invented this idea of the 

 origin of life as we now see it with the same instru- 

 ment, the mind, as that with which he would devise 

 a tent. He therefore not only imagined that living 

 things had been made just as he would make a 

 tent, but he also applied the same criterion of truth 

 to his explanation, as of trustworthiness to his tent. 

 If there was a flaw in the construction of his tent, 

 it would fall about his head in a storm. If there 

 were error in the making of his theory, it would 

 recoil upon him. But it did not recoil upon him ; 

 so apparently it was worthy of trust, it was true. 

 Or perhaps he thought, what a great many people 

 think to-day, that it does not really matter whether 

 the foundation of a theory of life is well and truly 

 laid. They think that a flaw in the construction 

 of an aeroplane may be fatal ; but they do not think 

 that a flaw in our theory of life can be fatal. But 

 in truth the difference between the two cases is 

 only one of degree. A flaw in the construction of 

 an aeroplane may endanger the life of one man ; 

 it may determine whether at a particular moment 

 he will live, or be dashed to the ground. But a 

 flaw in our conception of life may endanger the 

 whole of humanity, and condemn it to an existence 

 from which the sudden end of the airman would be 

 a merciful deliverance. For error in the construction 

 of a machine a man may have to pay down ; at 

 any rate, little credit is allowed. For error in the 

 interpretation of life much longer credit may be 

 allowed, but in the end the bill must be met ; and 

 in the long interval it may have grown to such a 



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