90 THE SCIENCE OF LOGIC 



the same genus of effect (e.g. death) can have only one and the 

 same genus of cause (viz. that generic element which is common 

 to all species of causes of death, making them all alike destructive 

 of life) ; one and the same species of effect (e.g. death from small 

 pox) can have only one and the same species of cause (viz. the 

 microbe of smallpox) ; any one individual effect (e.g. the death of 

 Julius Caesar) can (in its individual totality) have had only one 

 individual (total) cause, viz. that to which it was actually due. 1 



Now, in the mathematical sciences we establish numerous 

 universal truths which are reciprocal. 2 But is it always possible 

 to establish reciprocal causal relations in the inductive sciences? 

 On the contrary, it is rarely possible. Some logicians set it up 

 as an ideal at which the scientist must always aim. He is told 

 to commence his scientific investigations by working with the 

 popular concept of cause, which admits &quot; plurality of causes,&quot; and 

 to try to approximate gradually towards the scientific concept 

 which excludes plurality. Dr. Mellone s expression of this theory 

 is clear and accurate. &quot; In the absence of scientific knowledge of 

 the immediate cause, we have to bear in mind that different 

 combinations of circumstances may bring about the same event. 

 Practically we have to begin the investigation by examining those 

 different combinations of circumstances in which the event is 

 produced considering them, at first, as so many different 

 causes . They are not the immediate cause ; but it is operative 

 in them.&quot;* We are to commence, therefore, with the various 

 distinct modes (&quot; causes &quot; in the popular sense) of producing a 

 certain kind of effect, and to finish by abstracting what is common 

 and essential in all of them (the &quot; cause &quot; in the stricter sense). 



But this ideal is often unattainable, and, if attained, would be often com 

 paratively useless and uninstructive ; and this is so because &quot; the phenomenon 

 under investigation is often highly complex, and subject to all sorts of varia 

 tion on the different occasions of its occurrence, through variations in the 



1 Cf. JOSEPH, op cit., p. 65 : &quot; Whenever science tries to find the cause not of 

 a particular event, such as the French Revolution (whose cause must be as unique 

 as that event itself is), but of an event of a kind, such as consumption, or com 

 mercial crises, it looks in the last resort for a commensurate cause. What is that 

 exact state or condition of the body, given which it must and without which it can 

 not be in a consumption ? What are those conditions in a commercial community, 

 given which there must and without which there cannot be a commercial crisis ? &quot; 

 The same is true, of course, in regard to the cause of a &quot; particular event &quot; except 

 that this is regarded as belonging to the domain of history, not of science, which 

 is &quot; of the universal &quot;. 



3 Cf. JOSEPH, op. cit., pp. 443, supra, 212. 3 MIJLLONE, op. cit., p. 277. 



