98 PROCEEDINGS OF SECTION A. 
actual experience, or we make deductions from the first 
and second laws of thermodynamics. Law I.: ‘“‘ When 
mechanical energy is produced from heat, a definite quan 
tity of heat goes out of existence for every unit of work 
done; and conversely, when heat is produced by the expen- 
diture of mechanical energy, the same definite quantity of 
heat comes into existence for every unit of work spent.” 
Law II.: “It is impossible for a self-acting machine, un- 
aided by any external agency, to convey heat from one body 
to another at a higher temperature.” Any “ explanation ”’ 
that refers phenomena to such “laws”’ as these can surely 
not be described as a reference of the unknown to the 
known. A similar remark might be made about Maxwell’s 
law of partition of energy, and most of the socalled 
“laws”? of thermodynamics. Lastly, in light and elec- 
tricity, we “explain” everything by motions in the ether, 
which, for aught anyone can say, may be a mere figment of 
the imagination. 
I have not cited all these examples of scientific method 
with the object of criticising our science. I have just as 
much respect for the doctrine of energy or the idea of the 
ether as most men of science. My object has been to point 
out, not that the method is wrong, but that its aim is cer 
tainly not explanation. What, then, is the end of science? 
Its end is the purely practical one of enabling us to master 
the world. We are confronted with countless phenomena, 
and it is incumbent on us to know as much as possible, and 
to be able to communicate our knowledge. Otherwise we 
cannot progress, for Nature never pardons blunders. While 
the world was very young, men might do with a knowledge 
of a few facts; there would be comparatively little necessity 
for helps to piece the facts together. But, as civilisation 
advances, the need for colligating principles becomes more 
and more pressing. In modern life scientific research is 
daily adding to the sum of things that we must know, if we 
are to live, and not slip back. Hence we must have some 
means of relieving our memories of the burdensome know- 
ledge of isolated facts. This we require, not only for the 
practical needs of life, but also to satisfy our mental longing 
to grasp the whole world, or as much of it as possible. Thus 
we need general principles, or “laws” (if we prefer to style 
them so), that will string together our knowledge. It is the 
aim of science to lay down these general principles, and, hav- 
ing laid them down, to show that all the varied facts of 
experience are deducible therefrom. What is ordinarily 
