THE METHOD OF SCIENTIFIC 

 INVESTIGATION ' 



PHYSICAL science is one and indivisible. Although, 

 for practical purposes, it is convenient to mark it out 

 into the primary regions of Physics, Chemistry, and 

 Biology, and to subdivide these into subordinate prov- 

 inces, yet the method of investigation and the ultimate 

 object of the physical inquirer are everywhere the same. 



The object is the discovery of the rational order 

 which pervades the universe; the method consists of 

 observation and experiment (which is observation under 

 artificial conditions) for the determination ,of the facts 

 of Nature; of inductive and deductive reasoning for the 

 discovery of their mutual relations and connection. The 

 various branches of physical science differ in the extent 

 to which, at any given moment of their history, obser- 

 vation on the one hand, or ratiocination on the other, 

 is their more obvious feature, but in no other way; and 

 nothing can be more incorrect than the assumption one 

 sometimes meets with, that physics has one method, 

 chemistry another, and biology a third. 



All physical science starts from certain postulates. 

 One of them is the objective existence of a material 

 world. It is assumed that the phenomena which are 



1 This extract is taken from an essay, The Progress of Science, 

 written in 1887 for The Reign of Queen Victoria, by T. H. Ward. 

 The essay is published in Methods and Results, Collected Es- 

 says, I. 



37 



