THE STABILITY OF TRUTH. 343 
plausible? Has it logical continuity? Is it satisfying 
to the human heart?” And in this connection the fig- 
urative word “heart” is best left undefined. In other 
words, the sources and tests of philosophy are alike 
subjective, intellectual or emotional. If we take from 
philosophy the “heart ” element, the personal equation, 
it becomes logic or mathematics. Mathematics is meta- 
physics working through methods of precision. It is 
a most valuable instrument for the study of the rela- 
tions and ramifications of knowledge, but it can give no 
addition to knowledge itself. Dr. William James defines 
metaphysics as “ the persistent attempt to think clearly.” 
This definition is good so far as it goes, but to think 
clearly is a function of science also. Metaphysics is 
rather the “attempt to think clearly” in fields where 
exact data are unattained or unattainable. 
For example, the claim is made in the name of evo- 
lutionary philosophy that all matter is one in essence, 
therefore all the chemical elements, 
some seventy in number, must be the 
same in substance. In this case all must be derived 
from the same primitive stuff, and the hypothetical basis 
of all ponderable matter has been called protyl. Asa 
working theory this is most ingenious. But is it science? 
Is it worthy of belief ? Certainly science knows nothing 
as yet of the identity of these elements. Ina general 
way science is finding out that the processes of Nature 
are more complex than man had supposed, while the 
elements on which these processes rest, matter and 
force, are more simple. How far can this generaliza- 
tion go? To every test human experience has devised 
each chemical element remains the same, its atoms un- 
changeable as well as indestructible. Therefore to 
speak of them as forms of one substance is to go beyond 
knowledge. Science does not teach this, But to phi- 
Protyl. 
