688 LOGIC OF THE MORAL SCIENCES. 



only, or, if in all, only in a slight degree, have not been sufficiently ascer- 

 tained and studied to enable us to lay down their laws ; still less to deduce 

 the completed law of the phenomenon, by compounding the effects of the 

 greater with those of the minor causes. Tidology, therefore, is not yet 

 an exact science ; not from any inherent incapacity of being so, but from 

 the difficulty of ascertaining with complete precision the real derivative uni- 

 formities. By combining, however, the exact laws of the greater causes, 

 and of such of the minor ones as are sufficiently known, with such empir- 

 ical laws or such approximate generalizations respecting the miscellaneous 

 variations as can be obtained by specific observation, we can lay down 

 general propositions which will be true in the main, and on which, with 

 allowance for the degree of their probable inaccuracy, we may safely 

 ground our expectations and our conduct. 



§ 2. The science of human nature is of this description. It falls far 

 short of the standard of exactness now realized in Astronomy ; but there is 

 no reason that it should not be as much a science as Tidology is, or as As- 

 tronomy was when its calculations had only mastered the main phenome- 

 na, but not the perturbations. 



The phenomena with which this science is conversant being the thoughts, 

 feelings, and actions of human beings, it would have attained the ideal per- 

 fection of a science if it enabled us to foretell how an individual would 

 think, feel, or act throughout life, with the same certainty with which as- 

 tronomy enables us to predict the places and the occultations of the heaven- 

 ly bodies. It needs scarcely be stated that nothing approaching to this can 

 be done. The actions of individuals could not be predicted with scientific 

 accuracy, were it only because we can not foresee the whole of the circum- 

 stances in which those individuals will be placed. But further, even in any 

 given combination of (present) circumstances, no assertion, which is both 

 precise and universally true, can be made respecting the manner in which 

 human beings will think, feel, or act. This is not, however, because every 

 person's modes of thinking, feeling, and acting do not depend on causes; 

 nor can we doubt that if, in the case of any individual, our data could be 

 complete, we even now know enough of the ultimate laws by which mental 

 phenomena are determined, to enable us in many cases to predict, with tol- 

 erable certainty, what, in the greater number of supposable combinations of 

 circumstances, his conduct or sentiments would be. But the impressions and 

 actions of human beings are not solely the result of their present circum- 

 stances, but the joint result of those circumstances and of the characters of 

 the individuals; and the agencies which determine human character are 

 so numerous and diversified (nothing which has happened to the person 

 throughout life being without its portion of influence), that in the aggregate 

 they are never in any two cases exactly similar. Hence, even if our science 

 of human nature were theoretically perfect, that is, if we could calculate any 

 character as we can calculate the orbit of any planet, /rom given data; still, 

 as the data are never all given, nor ever precisely alike in different cases, 

 we could neither make positive predictions, nor lay down universal j)ropo- 

 sitions. 



Inasmuch, however, as many of those effects Avhich it is of most impor- 

 tance to render amenable to human foresight and control are determined, 

 like the tides, in an incomparably greater degree by general causes, than by 

 all partial causes taken together ; depending in the main on those circum- 

 stances and qualities which are common to all mankind, or at least to large 



