CHAP. VIII.] ESSAYS AT CAMBRIDGE. 239 



effect is absurd, a cause by its apparent frustration only 

 suggests the notion of an equal and opposite cause. 



" Now the analogy between reasons, causes, forces, prin- 

 ciples, and moral rules, is glaring, but dazzling. 



" A reason or argument is a conductor by which the mind 

 is led from a proposition to a necessary consequence of that 

 proposition. In pure logic reasons must all tend in the same 

 direction. There can be no conflict of reasons. We may lose 

 sight of them or abandon them, but cannot pit them against 

 one another. If our faculties were indefinitely intensified, 

 so that we could see all the consequences of any admission, 

 then all reasons would resolve themselves into one reason, and 

 all demonstrative truth would be one proposition. There 

 would be no room for plurality of reasons, still less for 

 conflict. But when we come to causes of phenomena and 

 not reasons of truths, the conflict of causes, or rather the 

 mutual annihilation of effects, is manifest. Not but what 

 there is a tendency in the human mind to lump up all 

 causes, and give them an aggregate name, or to trace chains 

 of causes up to their knots and asymptotes. Still we see, 

 or seem to see, a plurality of causes at work, and there are 

 some who are content with plurality. 



" Those who are thus content with plurality delight in the 

 use of the word force as applied to cause. Cause is a meta- 

 physical word implying something unchangeable and always 

 producing its effect. Force on the other hand is a scientific 

 word, signifying something which always meets with opposi- 

 tion, and often with successful opposition, but yet never fails 

 to do what it can in its own favour. Such are the physical 

 forces with which science deals, and their maxim is that 

 might is right, and they call themselves laws of nature. 

 But there are other laws of nature which determine the 

 form and action of organic structure. These are founded 

 on the forces of nature, but they seem to do no work except 

 that of direction. Ought they to be called forces ? A 

 force does work in proportion to its strength. These direct 

 forces to work after a model. They are moulds, not forces. 



