"The whole field of Deductive Logic, even when thought of merely in the terms of common language, has acquired, for the student of , a symmetry and a completeness and a simplicity which it is, apparently, far from possessing in the minds of its usual exponents. The natural repugnance which the ordinary logician felt, at first, to seeing processes of deductive reasoning made the subject of a great development by a purely mechanical process, has in great part passed away; it would have been hard for it to survive the eloquent persuasiveness of 's Symbolic Logic. It seems, therefore, to be time for the simplified ways of looking at things which prevail in Symbolic Logic to begin to sink into the elementary expositions of the subject."