10 THE UNFATHOMED UNIVERSE 



tions ? (a) First, instead of explaining an event by show- 

 ing that it obeys a law of Nature, the modern investigator is 

 content to say that it is fully described or represented in 

 such and such a formula, that it can be included in this 

 or that typical case. As Aristotle said, from a great number 

 of experiences one general conception is formed which will 

 embrace all similar cases. There is unification under a 

 common law. As Clifford says, " A true explanation refers 

 the previously unknown to the known." It assimilates the 

 less known to the better known. But we must not overlook 

 the preliminary analysis and reduction to a common denom- 

 inator which made it possible to bring an apparent incom- 

 mensurable into a series, and to recognise unity and 

 continuity of process. Equations may not be explanations, 

 but the analytic descriptions given by exact science are very 

 different from the pictorial descriptions of everyday life. 

 There is sometimes a mock modesty in the declaration of the 

 scientific inquirer that he is describing not explaining; and 

 there is deceptiveness in his formulation, if he reaches his 

 simplification by violence, by a jugglery which coerces to a 

 common denominator such fractions of reality as motion and 

 emotion which are radically incommensurable. 



(h) Second, there are laws of Nature such as Gravita- 

 tion, which sum up uniformities in terms largely independ- 

 ent of hypothetical constructions. These must be distin- 

 guished from summations in terms of what Rankine called 

 " conceptions of a conjectural order " which image the inti- 

 mate nature of things and processes. Ohm's laws remain, 

 whatever be our view of electrical energy. Mendel's law 

 remains, whatever be our views as to what are called ^ fac- 

 tors ' in inheritance. As long as we consider moving bodies 

 in bulk within sensible distances of the earth, the law of 



