FUNCTIONS AND VALUE OF THE SYLLOGISM. 139 



CHAPTER III. 



OF THE FUNCTIONS ANB LOGICAL VALUE OP THE SYLLOGISM. 



§ 1. We have shown what is the real nature of the truths with which 

 the Syllogism is conversant, in contradistinction to the more superficial 

 manner in which their import is conceived in the common theory; and 

 what are the fundamental axioms on which its probative force or conclu- 

 siveness depends. We have now to inquire, whether the syllogistic proc- 

 ess, that of reasoning from generals to particulars, is, or is not, a j^rocess 

 of inference ; a progress from the known to the unknown : a means of com- 

 ing to a knowledge of something which we did not know before. 



Logicians have been remarkably unanimous in their mode of answering 

 this question. It is universally allowed that a syllogism is vicious if there 

 be any thing more in the conclusion than was assumed in the premises. 

 But this is, in fact, to say, that nothing ever was, or can be, proved by syl- 

 logism, which was not known, or assumed to be known, before. Is ratioci- 

 nation, then, not a process of inference ? And is the syllogism, to which 

 the word reasoning has so often been represented to be exclusively appro- 

 priate, not really entitled to be called reasoning at all ? This seems an in- 

 evitable consequence of the doctrine, admitted by all writers on the sub- 

 ject, that a syllogism can prove no more than is involved in the premises. 

 Yet the acknowledgment so explicitly made, has not prevented one set of 

 writers from continuing to represent the syllogism as the correct analysis 

 of what the mind actually performs in discovering and proving the larger 

 half of the truths, whether of science or of daily life, which we believe; 

 while those who have avoided this inconsistency, and followed out the gen- 

 eral theorem respecting the logical value of the syllogism to its legitimate 

 corollary, have been led to impute uselessness and frivolity to the syllogis- 

 tic theory itself, on the ground of the petitio principii which they allege 

 to be inherent in every syllogism. As I believe both these opinions to be 

 fundamentally erroneous, I must request the attention of the reader to cer- 

 tain considerations, without which any just appreciation of the true char- 

 acter of the syllogism, and the functions it performs in philosophy, appears 

 to me impossible ; but which seem to have been either overlooked, or in- 

 sufficiently adverted to, both by the defenders of the syllogistic theory and 

 by its assailants. 



§ 2. It must be granted that in every syllogism, considered as an 



though it may be proper to limit the term Deduction to the application of a general principle 

 to a special case, it has never been held that Ratiocination or Syllogism is subject to the same 

 limitation ; and the adoption of it would exclude a great amount of valid and conclusive syl- 

 logistic reasoning. Moreover, if the dictum de omni makes prominent the fact of the applica- 

 tion of a general principle to a particular case, the axiom I propose makes prominent the 

 condition which alone makes that application a real inference. 



I conclude, therefore, that both forms have their value, and their place in Logic. The 

 dictum de omni should be retained as the fundamental axiom of the logic of mere consistency, 

 often called Formal Logic ; nor have I ever quarreled with the use of it in that character, 

 nor proposed to banish it from treatises on Formal Logic. But the other is the proper axiom 

 for the logic of the pursuit of truth by way of Deduction ; and the recognition of it can alone 

 show how it is possible that deductive reasoning can be a road to truth. 



