S 6 SCIENTIFIC METHOD IN PHILOSOPHY 



those were all the men there are, which is a general pro- 

 position. If we knew every other existing thing through- 

 out the universe, and knew that each separate thing was 

 not an immortal man, that would not give us our result 

 unless we knew that we had explored the whole universe, 

 i.e. unless we knew " all things belong to this collection 

 of things I have examined." Thus general truths cannot 

 be inferred from particular truths alone, but must, if they 

 are to be known, be either self-evident, or inferred from 

 premisses of which at least one is a general truth. But 

 all empirical evidence is of particular truths. Hence, if 

 there is any knowledge of general truths at all, there must 

 be some knowledge of general truths which is independent 

 of empirical evidence, i.e. does not depend upon the data 

 of sense. 



The above conclusion, of which we had an instance in 

 the case of the inductive principle, is important, since it 

 affords a refutation of the older empiricists. They 

 believed that all our knowledge is derived from the 

 senses and dependent upon them. We see that, if this 

 view is to be maintained, we must refuse to admit that 

 we know any general propositions. It is perfectly possible 

 logically that this should be the case, but it does not 

 appear to be so in fact, and indeed no one would dream 

 of maintaining such a view except a theorist at the last 

 extremity. We must therefore admit that there is general 

 knowledge not derived from sense, and that some of this 

 knowledge is not obtained by inference but is primitive. 



Such general knowledge is to be found in logic. 

 Whether there is any such knowledge not derived from 

 logic, I do not know ; but in logic, at any rate, we have 

 such knowledge. It will be remembered that we excluded 

 from pure logic such propositions as, " Socrates is a man, 

 all men are mortal, therefore Socrates is mortal," because 



