EDITOR'S TABLE. 



621 



correspond to the realities; their mental 

 pictures misrepresent. The man of sci- 

 ence imagines frames a view as the 

 initial step of all his procedures; and 

 then, by the mental processes of com- 

 parison, reasoning, inference, proof 

 guided by observation and experiment 

 he strives to give truth to his view ; 

 that is, to harmonize it with facts, and 

 all its parts with each other. Our writer 

 says that science starts with observa- 

 tion and experiment, but the real start- 

 ing-point is farther back. A mental 

 representation must be made before it 

 can be verified. A certain state of 

 tilings is conceived or put together in 

 thought, and is called an hypothesis; and 

 then observation and experiment are 

 appealed to, to test the correctness of 

 the representation the truthfulness of 

 the mental picture. Science is not 

 merely seeing with the eye or fumbling 

 with instruments any blockhead can 

 do these but it is to reconstruct Nature 

 in thought, representing all her diverse 

 objects, subtile relations, and complexi- 

 ties of change, so truly, that by every 

 test the representation shall answer to 

 the verities. To do this, the imagination 

 or image-forming faculty comes into in- 

 cessant play. And more than this, the 

 genius of the discoverer depends, first 

 of all, upon the vividness of his imagi- 

 nation and the power of keeping his 

 pictures steadily before the mind's eye 

 until their errors are detected or their 

 accuracy established. The work of sci- 

 ence, in fact, consists, from first to last, 

 in the verification of mental pictures. 

 The scientific man must be fertile in 

 imaginative resources, but stern in his 

 rejection of views that cannot be ad- 

 justed to facts. The poet has no such 

 discipline, for his object is not truth. 

 The theologian has no such discipline, 

 for he cannot submit his views to ob- 

 servation and experiment, so as to test 

 their congruity with the objective world 

 and with each other. The picturing 

 faculty is employed by all minds, but 

 only the trained scientist makes it sub- 



servient to the true understanding of 

 the order of tilings around. 



Sufficient has been said to show that 

 imagination is indispensable to science ; 

 but it may be asked, " If observation and 

 experiment are the means of science for 

 controlling the imagination, and if they 

 furnish the conditions of its valid exer- 

 cise, why prolong the vision beyond the 

 line of experimental evidence?" The 

 reply is, that senses and instruments are 

 imperfect, and their indications require 

 to be supplemented by reason. They 

 break down at a certain point, but that 

 point is very far from being the limit 

 of Nature. As experiments are per- 

 fected, the line of sensible demonstra- 

 tion is pushed backward constantly, dis- 

 closing a continuous order. It is a 

 right of reason and a legitimate pro- 

 cedure of science, to pursue this order, 

 if the explication of known phenomena 

 require it. The results, of course, must 

 conform to what is established must 

 harmonize with all that observation and 

 experiment have gained; but thought 

 may be compelled to go far deeper than 

 experiment for the explanation of facts 

 already known. 



To make this statement more con- 

 crete, let us take the very case put by 

 Prof. Tyndall the ultimate constitu- 

 tion of matter. By various lines of 

 proof, the physicist is brought to the 

 conclusion that there are such things as 

 amazingly-minute physical units which 

 he calls molecules. In their smallness 

 they are far beyond the border of all 

 sensible observation ; but he is driven 

 to the conclusion that they exist as reali- 

 ties, and he has to represent them in 

 thought. He mentally pictures a mole- 

 cule as the smallest particle of matter 

 that can exist separately and retain its 

 physical properties. Prof. Thompson 

 finds physical and mathematical evi- 

 dence pointing down to the actual size 

 of molecules. From this he infers that 

 those of water have diameters that 

 fall within the limits of ^soaooooo an( l 

 s aoo ^oooc, of an inch ; and adds that, if 



