CHAPTER I. 



GENERAL RELATIONS BETWEEN THE PHYSICAL AND THE MORAL. 



I. 



To inquire into causes we must hazard hypotheses. This cannot 

 be avoided ; for though science begins with the investigation of 

 laws, it is perfected only in the determination of causes. Here, 

 too, as in every experimental study, we have only to deal with 

 secondary and immediate causes, or, in plainer terms, with in- 

 variable antecedents. As far as our purpose is concerned, to 

 explain physiological heredity means to define an aggregate of 

 conditions, of such a nature that if these conditions are present 

 heredity necessarily follows, and when they are wanting heredity 

 is invariably wanting. In what follows, therefore, there is no 

 question of ultimate causes ; and, without inquiring here whether 

 they are accessible or inaccessible to the human mind, we shall 

 never speak of them except with the admission that we are 

 entering on hypotheses. 



Heredity is only a special case of the great problem of the 

 relations between physics and morals, as will more clearly appear 

 in the course of this work. We can, however, note in advance, 

 in a more precise way, the position of our question, by observing 

 that every inquiry into the relations between physics and morals 

 necessarily comprises two parts, the influence of the moral on the 

 physical, and the influence of the physical on the moral. The pro- 

 blem of heredity is concerned only with the latter. The influence 

 of physics on morals manifests itself in many ways, of which we 

 here consider one only, heredity. With this explanation we can now 

 indicate the line of inquiry we shall follow in our study of causes. 



We shall, in the first place, examine in a very general way the 

 relations between the physical and the moral, as the problem in 

 its most general form necessarily governs all the particular cases. 



