236 METAPHYSICS 



Thus it might be fairly said to be the supreme science of order, and 

 it would not be hard to show that all the special questions commonly 

 included in its range, as to the nature of space, time, causation, con- 

 tinuity, and so forth, are all branches of the general question, how 

 many types of order among concepts are there, and what is their 

 nature. A completed metaphysics would thus appear as the realiza- 

 tion of Plato's splendid conception of dialectic as the ultimate reduc- 

 tion of the contents of knowledge to order by their continuous de- 

 duction from a supreme principle (or, we may add, principles). Now 

 such a view seems to make it almost impossible to draw any ulti- 

 mate distinction between logic and metaphysics. For logic is strictly 

 the science of the mutual implication of propositions, as we see as 

 soon as we carefully exclude from it all psychological accretions. In 

 the question what are the conditions under which one proposition 

 or group of propositions imply another, we exhaust the whole scope 

 of logic pure and proper, as distinguished from its various empirical 

 applications. This is the important point which is so commonly 

 forgotten when logic is defined as being in some way a study of " psy- 

 chical processes," or when the reference to the presence of "minds" 

 in which propositions exist, is intended into logical science. We can- 

 not too strongly insist that for logic the question so constantly raised 

 in a multitude of text-books, what processes actually take place when 

 we pass from the assertion of the premises to the assertion of the 

 conclusion, is an irrelevant one, and that the only logical problem 

 raised by inference is whether the assertion of the premises as true 

 warrants the further assertion of the conclusion, supposing it to be 

 made. (At the risk of a little digression I cannot help pointing out that 

 the confusion between a logical and a psychological problem is com- 

 mitted whenever we attempt, as is so often done, to make the self- 

 evidence of a principle identical with our psychological inability to 

 believe the contradictory. From the strictly logical point of view, 

 all that is to be said about the two sides of such an ultimate contra- 

 diction is that the one is true and the other is false. Whether it is 

 or is not possible, as a matter of psychical fact for me to affirm with 

 equal conviction, both sides of a contradiction, knowing that I am 

 doing so, is a question of empirical psychology which is possibly 

 insoluble, and at any rate seems not to have received from the 

 psychologists the attention it deserves. But the logician, so far as 

 I can see, has no interest as a logician in its solution. For him it 

 would still be the case even though all mankind should actually and 

 consciously affirm both sides of a given contradiction, that one of the 

 affirmations would be true, and the other untrue.) Logic thus seems 

 to become either the whole or an integral part of the science of order, 

 and there remain only two possible ways of distinguishing it from 

 metaphysics. It might be suggested that logical order, the order of 



