648 Transactions. — Miscellaneous. 



glide into fallacious thinking by forgetting that it is this and 

 nothing niore."^'- 



Professor Bain thinks that in forming general conceptions 

 we can do one of two things : (1) we may call up an image 

 that embraces all the attributes of rivers in general, or (2) we 

 may call up the image of any particular river and use it as a 

 symbol by which to think of rivers in general. It is plain 

 enough that it is only the last of these two things that any 

 one can do. The concept " river," like every abstract concept, 

 is a schema or definition, not an image. It rests on a judg- 

 ment or a series of judgments. In the simplest possible case — 

 say, that of the concept " one " or the concept " blue" — there 

 is, at any rate, behind such concepts the judgment that the 

 name " one " or the name " blue " shall apply to the number 

 " one " and the colour "blue" exclusively, and not to any 

 other colour or number. This judgment is what Professor 

 Huxley somewhere calls " the convention that underlies in- 

 telligible speech." He might have added, "that underlies 

 rational thought." It is this judgment that is contradicted 

 when we say, " One is two," or " Blue is green." Behind the 

 mere sensation caused by one object, or by a blue object, there 

 is, of course, no judgment to contradict. And it appears to be 

 the easiest thing possible for even the very acutest thinkers to 

 confound, in this respect, the sensation with the concept. 

 To deny "that blue is not green," Mr. Mill says, "involves 

 no logical contradiction. We could believe that a green 

 thing may be blue as easily as we believe that a round thing 

 may be blue if experience did not teach us the incompatibility 

 of the former attributes and the compatibility of the latter."! 

 This is all based upon the assumption that to affirm, " Green 

 is not blue," is equivalent to affirming, " This green thing 

 before me is not a blue thing;" while what it is really 

 equivalent to is, " If this thing is green it is not blue." It is 

 " a proposition concerning a proposition, the subject of the 

 assertion being itself an assertion."! " Two straight lines 



*Mr. Mill, for instance, as will be seen further down, affirms that the 

 reason why, in his view, we can gain from experience what seems to be 

 axiomatic certainty in regard to geometrical truths, is to be found in the 

 capacity of geometrical forms for being painted in the imagination with 

 a distinctness equal to reality. We can thus, he says, copy lines and 

 figures, and argue from the copies as we would from the realities. 

 Granted that we can copy them as well in imagination as on a black- 

 board, what wo argue from is not the specimen on the board, but the rule 

 in accordance with which, or perhaps only in a rough approximation to 

 which, it is drawn. This fallacy of confounding the functions of the 

 specimen with those of the schema has been a fruitful source of error. 



t " Examination of Sir W. Hamilton's Philosophy," 4th ed., p. 486. 



I Mill's definition of a conditional proposition. " Logic," People's 

 Ed., p. 53. 



