t72 



HEASONING. 



ously the place which belongs to it, 

 and will receive its share of whatever 

 light may be thrown upon the great 

 intellectual operation of which it forms 

 80 important a part. 



CHAPTER VIL 



EXAMINATION OF SOME OPINIONS OP- 

 POSED TO THE PRECEDING DOC- 

 TRINES. 



§ I. Polemical discussion is foreign 

 to the plan of this work. But an 

 opinion which stands in need of much 

 illustration can often receive it most 

 effectually, and least tediously, in the 

 form of a defence against objections. 

 And on subjects concerning which 

 speculative minds are still divided, a 

 writer does but half his duty by 

 stating his own doctrine, if he does not 

 also examine, and to the best of his 

 ability judge, those of other thinkers. 



In the dissertation which Mr. 

 Herbert Spencer has prefixed to his, 

 in many respects, highly philosophical 

 treatise on the mind,* he criticises 

 some of the doctrines of the two pre- 

 ceding chapters, and propounds a 

 theory of his own on the subject of 

 first principles. Mr. Spencer agrees 

 with me in considering axioms to be 

 " simply our earliest inductions from 

 experience." But he differs from me 

 " widely as to the worth of the test of 

 inconceivableness." He thinks that 

 it is the ultimate test of all beliefs. 

 He arrives at this conclusion by two 

 steps. First, we never can have any 

 stronger ground for believing anything 

 than that the belief of it " invariably 

 exists." Whenever any fact or pro- 

 position is invariably believed — that 

 is, if I understand Mr. Spencer rightly, 

 believed by all persons, and by one- 

 self at all times— it is entitled to be 

 received as one of the primitive truths 

 or original premises of our knowledge. 

 Secondly, the criterion by which we 

 decide whether anything is invariably 



* JPrineiplet of Psychology. 



believed to be true is our inability to 

 conceive it as false. "The incon- 

 ceivability of its negation is the test 

 by which we ascertain whether a given 

 belief invariably exists or not." 

 " For our primary beliefs, the fact of 

 invariable existence, tested by an 

 abortive effort to cause their non- 

 existence, is the only reason assign- 

 able." He thinks this the sole ground 

 of our belief in our own sensations. 

 If I believe that I feel cold, I only 

 receive this as true because I cannot 

 conceive that I am not feeling cold. 

 " While the proposition remains true, 

 the negation of it remains inconceiv- 

 able." There are numerous other be- 

 liefs which Mr. Spencer considers to 

 rest on the same basis, being chiefly 

 those, or a part of those, which the 

 metaphysicians of the Reid and 

 Stewart school consider as truths of 

 immediate intuition. That there ex- 

 ists a material world ; that this is the 

 very world which we directly and im- 

 mediately perceive, and not merely the 

 hidden cause of our perceptions ; that 

 Space, Time, Force, Extension, Figure, 

 are not modes of our consciousness, 

 but objective realities ; are regarded 

 by Mr. Spencer as truths known by 

 the inconceivableness of their nega- 

 tives. We cannot, he says, by any 

 effort, conceive these objectsof thought 

 as mere states of our mind ; as not 

 having an existence external to us. 

 Their real existence is, therefore, as 

 certain as our sensations themselves. 

 The truths which are the subject of 

 direct knowledge, being, according to 

 this doctrine, known to be truths only 

 by the inconceivability of their nega- 

 tion, and the truths which are not 

 the object of direct knowledge, being 

 known as inferences from those which 

 are : and those inferences being be- 

 lieved to follow from the premises 

 only because we cannot conceive them 

 not to follow, inconceivability is thus 

 the ultimate ground of all assured 

 beliefs. 



Thus far there is no very wide dif- 

 ference between Mr. Spencer's doc- 

 trine and the ordinary one of philo- 



