632 



SCIENCE. 



[N. S. Vol. III. No. 69. 



of irrelevant discussion on side issues, one of 

 your readers (M. M.), has at last found the 

 thesis of my article on Science and Poetry 

 (Science Oct. 4, 1895,) worthy of consideration. 



While I take issue with M. M., I thank him 

 for this opportunity to give, once more, my 

 reasons for the belief that is in me that there is 

 only one kind of knowledge and but one way 

 to acquire it. 



I hope I may be permitted to say, in intro- 

 duction, that I have no sympathy with those 

 who hold that science is inductive or nothing. 

 1 yield to no one in reverence for mathematics. 

 I wish it had been my good fortune to be more 

 familiar with the deductive or ' abstract ' 

 sciences, for I believe they are the best products 

 of the human mind. I am prepared to stake 

 everything on their axioms, for I believe they 

 are a^Mi^ or worthy of all coniidence. I accept 

 the logical deductions from them as the best and 

 most trustworthy of all knowledge. 



All this is quite a different matter from the 

 admission that these axioms rest on anything but 

 evidence ; that they are ' necessary ;' or that 

 we have any way to deduce new truth from 

 them except the employment of that empirical 

 logic of events, which is based on evidence and 

 knowledge of the order of nature. I am ac- 

 quainted with no evidence that the mind is any- 

 thing more than ' an. accident to knowledge,' 

 or that knowledge is any thing but ' the double 

 of that which is.' 



In his comment on my assertion that the teat 

 of truth is evidence and nothing but evidence, 

 M. M. admits that evidence is a requisite test 

 for nearly all truths. I infer from this qualifi- 

 cation that he believes there are some truths 

 for which evidence is not necessary. 



If this means that some truths are already 

 supported by so much evidence that no more is 

 needed, I have nothing to say ; but I take it 

 that he believes with Hume, that certain truths 

 ' are discoverable by the mere operation of 

 thought, without dependence on what is any- 

 where existent in the universe.' 



His words are not very explicit; and if this 

 is not his meaning I beg his pardon, and I ask 

 leave to address this communication to those 

 readers of Science, if any there be, who do 

 believe in ' necessary truths. ' 



Like most students of the order of nature, I 

 feel my own unfitness to contend in argument 

 with one trained in dialectic, and I shall, there- 

 fore, attempt no more than a brief statement 

 of what I believe to be the opinion of most of 

 my scientific contemporaries concerning those 

 conceptions which are called axioms, innate 

 ideas, intuitive beliefs or necessary truths. 



When we ask proof that these conceptions 

 are innate ^ve get no direct evidence, but we 

 are told we must admit this, since we cannot 

 conceive their contrary. As M. M. acknowl- 

 edges that ' inconceivability is no test of falsity,' 

 he, at least, cannot make this reply; for, if his 

 words mean anything they mean that incon- 

 ceivable things may be true. We have no way 

 to discriminate between unknown things, and 

 anything which may be true may some time 

 prove true. 



If there were any reason to believe the 

 human mind is a finished instrument, perfect, 

 and a measure of the unknown, the argument, 

 that these beliefs are necessary because we can- 

 not conceive their contrary, might seem valid; 

 but no one who believes ' the subtilty of nature 

 is far beyond that of sense or of the under- 

 standing ' can admit that this proves they are 

 necessary in any sense of the word except the 

 practical one. We are able to spin fancies out 

 of our minds as a spider spins silk out of its 

 stomach, but I hope most readers of Science 

 agree that ' ' all this is but a web of the wit ; it 

 can work nothing." I hope they agree, also, 

 that the difference between truth and fancy is 

 evidence. 



We say, glibly enough, of this quintessence of 

 dust : ' ' What a piece of work is man '? How 

 noble in reason ! how infinite in faculties ! in 

 apprehension how like a god !" But it is per- 

 haps fortunate for our self esteem that we 

 have no opinion on the subject by any compe- 

 tent judge; and it is the height of folly to at- 

 tempt to measure the unknown by our own 

 minds. 



We are told, furthermore, that reasoning is 

 impossible unless these ' necessary ' truths are 

 admitted, and that, if they should ever cease 

 to hold good, the result would be madness and 

 destruction. This may be true, for all I know, 

 but if the human race is ever overwhelmed in 



