182 EEASONING. 



appearances familiar from the first dawn of intelligence, and of the conclu- 

 siveness of which, from the earliest records of human thought, no skeptic 

 has suggested even a momentary doubt ? 



The other instance which I shall quote is a truly astonishing one, and 

 may be called the rediictio ad absurdum of the theory of inconceivableness. 

 Speaking of the laws of chemical composition, Dr. Whewell says :* " That 

 they could never have been clearly understood, and therefore never firmly 

 established, without laborious and exact experiments, is certain ; but yet 

 we may venture to say, that being once known, they possess an evidence 

 beyond that of mere experiment. For hoio in fact can we conceive combi- 

 nations, otherwise than as definite in kind and quality?. If we were to 

 suppose each element ready to combine with any other indifferently, and 

 indifferently in any quantity, we should have a world in which all would be 

 confusion and indetiniteness. There would be no fixed kinds of bodies. 

 Salts, and stones, and ores, would approach to and graduate into each other 

 by insensible degrees. Instead of this, we know that the world consists of 

 bodies distinguishable from each other by definite differences, capable of 

 being classified and named, and of having general propositions asserted 

 concerning them. And as we can not conceive a world in which this 

 shoidd not he the case, it would appear that we can not conceive a state of 

 things in which the laws of the combination of elements should not be of 

 that definite and measured kind which we have above asserted." 



That a philosopher of Dr. Whewell's eminence should gravely assert 

 that we can not conceive a world in which the simple elements should com- 

 bine in other than definite proportions; that by dint of meditating on a 

 scientific truth, the original discoverer of which was still living, he should 

 have rendered the association in his own mind between the idea of combi- 

 nation and that of constant proportions so familiar and intimate as to be 

 unable to conceive the one fact without the other ; is so signal an instance 

 of the mental law for which I am contending, that one word more in illus- 

 tration must be superfluous. 



In the latest and most complete elaboration of his metaphysical system 

 (the Philosophy of Discovery), as well as in the earlier discourse on the 

 Fundamental Antithesis of Philosophy, reprinted as an appendix to that 

 work. Dr. Whewell, while very candidly admitting that his language was 

 open to misconception, disclaims having intended to say that mankind in 

 general can now perceive the law of definite proportions in chemical com- 

 bination to be a necessary truth. All he meant was that philosophical 

 chemists in a future generation may possibly see this. " Some truths may 

 be seen by intuition, but yet the intuition of them may be a rare and a dif- 

 ficult attainment."! And he explains that the inconceivableness which, ac- 

 cording to his theory, is the test of axioms, " depends entirely upon the 

 clearness of the Ideas which the axioms involve. So long as those ideas 

 are vague and indistinct, the contrary of an axiom may be assented to, 

 though it can not be distinctly conceived. It may be assented to, not be- 

 cause it is possible, but because we do not see cleai'ly what is possible. To 

 a person who is only beginning to think geometrically, there may appear 

 nothing absurd in the assertion that two straight lines may inclose a space. 

 And in the same manner, to a person who is only beginning to think of 

 mechanical truths, it may not appear to be absurd, that in mechanical proc- 

 esses. Reaction should be greater or less than Action ; and so, again, to a 



* Hist. Scientific Ideaa,\\., 2b, 2Q. ] Phil, of Disc, ^.d3,^. 



