194 NATURE AND MAN. 



The surest of such judgments are those dictated by what we term 

 &quot; common sense,&quot; as to matters on which there seems no room for 

 difference of opinion, because every sane person comes to the 

 same conclusion, although he may be able to give no other reason 

 for it than that it appears to him &quot; self-evident.&quot; Thus while philo 

 sophers have raised a thick cloud of dust in the discussion ot the 

 basis of our belief in the existence of a world external to ourselves 

 of the Non-Ego, as distinct from the Ego and while every 

 logician claims to have found some flaw in the proof advanced by 

 every other the common sense of mankind has arrived at a 

 decision that is practically worth all the arguments of all the 

 philosophers who have fought again and again over this battle 

 ground. And I think it can be shown that the trustworthiness 

 of this common sense decision arises from its dependence, not on 

 any one set of experience, but upon our unconscious co-ordination 

 of the whole aggregate of our experiences not on the conclusiveness 

 of any one train of reasoning, but on the convergence of all our 

 lines of tJwught towards this one centre. 



Now this &quot;common sense,&quot; disciplined and enlarged by appro 

 priate culture, becomes one of our most valuable instruments of 

 scientific inquiry ; affording in many instances the best, and some 

 times the only, basis for a rational conclusion. Let us take as a 

 typical case, in which no special knowledge is required, what we 

 are accustomed to call the &quot; flint implements &quot; of the Abbeville 

 and Amiens gravel-beds. No logical proof can be adduced that 

 the peculiar shapes of these flints were given to them by human 

 hands; but does any unprejudiced person now doubt it? The 

 evidence of design, to which, after an examination of one or two 

 such specimens, we should only be justified in attaching a probable 

 value, derives an irresistible cogency from accumulation. On the 

 other hand, the / ///probability that these flints acquired their 

 peculiar shape by accident, becomes to our minds greater and 

 greater as more and more such specimens are found; until at last 

 this hypothesis, although it cannot be directly disproved, is felt to 

 be almost inconceivable, except by minds previously &quot;possessed&quot; 

 by the &quot; dominant idea &quot; of the modem origin of man. And thus 

 what was in the first instance a matter of discussion, has now 

 become one of those &quot; self-evident &quot; propositions, which claim the 



