448 LOGIC OF THE MORAL SCIENCES. 



and simple, and yet the effects themselves may be so various 

 and complicated that it shall be impossible to trace any 

 regularity whatever completely through them. For the phe- 

 nomena in question may be of an eminently modifiable 

 character; insomuch that innumerable circumstances are 

 capable of influencing the effect, although they may all do it 

 according to a very small number of laws. Suppose that all 

 which passes in the mind of man is determined by a few simple 

 laws : still, if those laws be such that there is not one of the 

 facts surrounding a human being, or of the events which 

 happen to him, that does not influence in some mode or degree 

 his subsequent mental history, and if the circumstances of 

 different human beings are extremely different, it will be no 

 wonder if very few propositions can be made respecting the 

 details of their conduct or feelings, which will be true of all 

 mankind. 



Now, without deciding whether the ultimate laws of our 

 mental nature are few or many, it is at least certain that they 

 are of the above description. It is certain that our mental 

 states, and our mental capacities and susceptibilities, are 

 modified, either for a time or permanently, by everything 

 which happens to us in life. Considering therefore how 

 much these modifying causes differ in the case of any two 

 individuals, it would be unreasonable to expect that the 

 empirical laws of the human mind, the generalizations which 

 can be made respecting the feelings or actions of mankind 

 without reference to the causes that determine them, should 

 be anything but approximate generalizations. They are the 

 common wisdom of common life, and as such are invaluable ; 

 especially as they are mostly to be applied to cases not very 

 dissimilar to those from which they were collected. But 

 when maxims of this sort, collected from Englishmen, come 

 to be applied to Frenchmen, or when those collected from the 

 present day are applied to past or future generations, they are 

 apt to be very much at fault. Unless we have resolved the 

 empirical law into the laws of the causes on which it depends, 

 and ascertained that those causes extend to the case which we 

 have in view, there can be no reliance placed in our inferences., 



