XLIV THE ROYAL SOCIETY OF CANADA 
Darwin’s theory of natural selection was based on facts observed 
before hand; Maxwell’s electromagnetic theory was worked out by 
mathematical reasoning from an hypothesis, to be tested afterwards 
by experiments suggested by it. Usually, theorising and testing by 
observation or experiment proceed together. 
In observation, whether of naturally occurring or experimental 
phenomena, the highest possible degree of accuracy is called for. The 
smallest differences between objects must be noted. Changes of tem- 
perature, disturbing air-currents, vibrations or flexures of the apparatus, 
innumerable interfering causes, must be avoided or allowed for: even 
the accuracy of the observer’s senses must be tested; weighings and 
measurings must be performed with scrupulous care. Nothing must 
be taken for granted without verification. 
The investigator must be ready to theorise, but he must analyse 
his theories with the utmost thoroughness. However perfect or beautiful 
they may appear to him, he must keep an open mind, and deal with 
them impersonally, freeing himself from all bias, which might blind 
him to facts which do not agree with them. He must be ready to reject 
a theory if it is inconsistent with a single fact, but at the same time he 
owes it to himself and to science not to do so lightly, or until he has 
thoroughly investigated the discrepant phenomenon, lest he lose the 
opportunity to recognize a hidden law operating in opposition to that 
which he has assumed as the basis of his theory. When the evidence is 
insufficient he must suspend judgment. He must have the courage to- 
face the conclusions to which his theory leads. He must throughout 
be animated by the desire for truth, to attain as nearly as he can to the 
absolute reality of nature. 
Such is the ideal of the scientific investigator. However far 
individuals may fall short of it, research to be successful, demands in 
greater or less measure, the qualities described. Scientific training 
tends to develop them, and thereby to produce men who are of value 
to the community not only for what they know and can do in the par- 
ticular science that they cultivate, but also for what these qualities 
mean in the affairs of life and in matters affecting the public interest. 
Again, as I have pointed out, not only abstract science, but also 
applications of science, call for research. With so many practical 
workers in these applications, and so many interested in them, the 
accuracy of observation, the carefulness of analysis of facts and 
inferences, the boldness of well weighed judgment, taught by the 
methods of science, have to a great extent permeated the public mind. 
As a result, sociological questions are discussed more generally and 
more intelligently than ever before, while the example afforded by the 
organization of the forces of nature has borne fruit in organization for 
