PUNISHING A SENIOR WRANGLER. 151 



motion and the law of gravitation are true ; and that non-fulfillment 

 of the prediction would not disprove the first law of motion, since the 

 error might be in one or other of the three remaining assumptions. 

 Similarly with the second law : the astronomical proof of it depends 

 on the truth of the accompanying assumptions. So that the warrants 

 for the assumptions A, B, C, and D, are respectively such that A, B, 

 and C, being taken as trustworthy, prove the vaMity of D ; D being 

 thus proved valid, joins C, and B, in giving a character to A; and 

 so throughout. The result is that every thing comes out right if they 

 happen to be all true ; but, if one of them is false, it may destroy the 

 characters of the other three, though these are in reality exact. Clear- 

 ly, then, astronomical prediction and observation can never test any 

 one of the premises by itself. They can only justify the entire aggre- 

 gate of premises, mathematical and physical, joined with the entire ag- 

 gregate of reasoning processes leading from premises to conclusions. 



I now recall the reviewer's "thought," uttered in his habitual 

 manner, " that every tolerably educated man was aware that the proof 

 of a scientific law consisted in showing that, hy assuming its truth, we 

 could explain the observed phenomena." Having from the point of 

 view of ordinary logic dealt with this theory of proof as applied by 

 the reviewer, I proceed to deal with it from the point of view of tran- 

 scendental logic, as I have to charge the reviewer with either being 

 ignorant of, or else deliberately ignoring, a cardinal doctrine of the 

 System of Philosophy he professes to review — a doctrine set forth not 

 in those four volumes of it which he seems never to have looked into, 

 but in the one volume of it he has partially dealt with. For this 

 principle which, in respect to scientific beliefs, he enunciates for my 

 instruction, is one which, in " First Principles," I have enunciated in re- 

 spect to all beliefs whatever. In the chapter on the "Data of Philoso- 

 phy," where I have inquired into the legitimacy of our modes of pro- 

 cedure, and where I have pointed out that there are certain ultimate 

 conceptions without which the intellect can no more stir "than the 

 body can stir without help of its limbs," I have inquired how their 

 validity or invalidity is to be shown ; and I have gone on to reply 

 that— 



" Those of them which are vital, or cannot be severed from the rest without 

 mental dissolution, must be assumed as true prorisionaUy .... leaving the 

 assumption of their unquestionableness to be justified by the results. 



'' § 40. How is it to be justified by the results? As any other assumption is 

 justified — by ascertaining that all the conclusions deducible from it correspond 

 with the facts as directly observed— by showing the agreement between the ex- 

 periences it leads us to anticipate and the actual experiences. There is no 

 mode of establishing the validity of any belief, except that of showing its entire 

 congruity with all other beliefs." 



Proceeding avowedly and rigorously on this principle, I have next 

 inquired what is the fundamental process of thought by which this con- 



