SCIENCE AND DEMONSTRATION 239 



some strange fact, or new generalization, before we understand 

 the principles which really explain it. And we are enabled to 

 take it in if it is described for us in terms of some already known, 

 familiar facts. Such descriptions, by means of rough analogies 

 and illustrations, are very extensively employed in all attempts 

 at popularizing the truths of science, and bringing them somehow 

 or other within the mental horizon of the man in the street or the 

 youthful learner. And such descriptions are sometimes called 

 individual, or subjective, or popular &quot;explanations,&quot; because they 

 are addressed to individual minds that are not yet capable of 

 understanding the real explanation of the matters so described. 



To borrow an example quoted by Professor Welton from Clifford s Lectures 

 and Essays : J &quot;It is [a popular] explanation of the moon s motion to say that 

 she is a falling body, only she is going so fast and is so far off that she falls 

 quite round to the other side of the earth, instead of hitting it ; and so goes on 

 for ever &quot;. This does not give us the why or wherefore of the fact : it is not a 

 scientific explanation : We cannot understand the moon s motion scientifically 

 until we are able to refer it to the laws of motion and gravitation. &quot; But it is 

 no [popular] explanation to say that a body falls because of gravitation. That 

 means that the motion of the body may be resolved into a motion of every one 

 of its particles towards every one of the particles of the earth, with an accelera 

 tion inversely as the square of the distance between them. But this attraction 

 of two particles must always, I think, be less familiar than the original falling 

 body, however early the children of the future begin to read their Newton.&quot; 

 Therefore the latter explanation is not &quot;popular&quot; ; but it is &quot;scientific&quot; ; it 

 is an explanation by principles and causes and laws which are in themselves 

 prior to the concrete facts (priora in se, natura sua], though not more familiar 

 to us (priora et notiora quoad nos}. 



256. LIMITATIONS OF SCIENTIFIC EXPLANATION. If we regard scientific 

 explanation as the process of bringing particular facts under inductively 

 established laws, and of unifying these separate, isolated laws by bringing them 

 in turn under still wider and remoter inductive generalizations, then there arises 

 this peculiar difficulty : that we are explaining particular facts and narrower laws 

 by an appeal to wider ultimate laws which do not themselves admit of a similar 

 explanation. We saw something analogous in examining demonstration : it 

 also rests ultimately on principles that are themselves indemonstrable. But 

 then, these latter are self-evident, whereas the widest generalizations of induc 

 tion are not self-evident ; and hence Aristotle would not recognize the knowledge 

 based on these as &quot; scientific &quot; in the strict sense. But such knowledge is now 

 universally regarded as scientific ; and rightly so, for these ultimate inductive 

 laws have sufficient evidence of their truth in the facts of experience. They are 

 not intrinsically and immediately evident like the axioms of geometry, but they 

 are believed to be true because we see that they alone are compatible with the 

 facts of experience, or, at all events, that they furnish us with the most satis 

 factory explanation we can find for the facts of experience (221, 230). We 



J pp. 102-3, apud WELTON, op. cit., ii., p. 190. 



