54 THE SCIENCE OF LOGIC 



the whole ascent from particular to general cannot be intelligibly 

 described as an &quot; inductive syllogism,&quot; or as the opposite of the 

 &quot; deductive syllogism &quot;. We may, however, regard both pro 

 cesses in a light which will admit of their being compared and 

 contrasted. The relation of premisses to conclusion in the 

 syllogism is identical with the relation of antecedent to consequent 

 in a hypothetical proposition (134, 148, 165); the premisses or 

 antecedent being regarded as a &quot;ground&quot; or &quot;reason&quot; whose 

 affirmation gives us a right to affirm the conclusion or consequent, 

 though not as the sole, exclusive, only possible ground for affirming 

 the latter. Hence, given the antecedent, we may infer the conse 

 quent, though we cannot, conversely, affirm the antecedent if we 

 are given the consequent (140). In other words, a given logical 

 antecedent is regarded as necessitating some definite consequent, 

 while this same logical consequent is not regarded as definitely 

 necessitating that antecedent. Now, if we regard deduction as the 

 passage of thought from logical antecedent to logical consequent 

 (understanding these terms in the sense just indicated), deduction 

 may be described as a direct or definite process, reaching a de 

 finite result. And if we regard induction as the passage of 

 thought from the real consequent or effect, regarded as logical 

 consequent, to the real antecedent or cause, regarded as logical 

 antecedent, induction will appear to be an inverse or indefinite 

 process, reaching only indefinite results: since, for any given 

 effect, considered as logical consequent, there may be a plurality 

 of causes, considered as logical antecedents. This leads us to the 

 consideration of induction as an &quot; inverse problem,&quot; or &quot; inverse 

 process,&quot; in comparison with deduction regarded as a &quot; direct 

 problem,&quot; or &quot; direct process &quot;. 



In what sense, then, may induction be fairly described as an 

 &quot; inverse process,&quot; the inverse of deduction? It has been some 

 times so described by logicians. The term is borrowed from 

 mathematics, and there it has a quite intelligible meaning. A 

 direct process is one by which, given certain data and laws of 

 inference, we arrive at a definite conclusion : the inverse process 

 is that by which, given the conclusion, we try to get back to the 

 data. While the former always gives a definite result, the latter 

 may yield very indefinite ones. For example, given 4x4, what 

 is the product? Answer (definitely): 16. Given the product 

 1 6, what number multiplied by itself yields this product ? Answer 

 (indefinitely): plus 4, or minus 4. Or again, of what factors is 



