SEPTEMBER 22, 1899. ] 
survival of a much older conception of the 
scope of physical science, a mode of regard- 
ing physical phenomena which has itself 
passed away. 
IT imagine that originally man looked on 
himself and the result of his action in the 
motions and changes which he produced in 
matter, as the one type in terms of which 
he should seek to describe all motions and 
changes. Knowing that his purpose and 
will were followed by motions and changes 
in the matter about him, he thought of 
similar purpose and will behind all the mo- 
tions and changes which he observed, how- 
ever they occurred ; and he believed, too, 
that it was necessary to think thus in giv- 
ing any consistent account of his observa- 
tions. Taking this anthropomorphic—or, 
shall we say, psychical—view, the laws he 
formulated were not merely descriptions of 
similarities of behavior, but they were also 
expressions of fixed purpose and the result- 
ing constancy of action. They were com- 
mands given to matter which it must obey. 
The psychical method, the introduction 
of purpose and will, is still appropriate 
when we are concerned with living beings. 
Indeed, it is the only method which we at- 
tempt to follow when we are describing the 
motions of our fellow-creatures. No one 
seeks to describe the motions and actions of 
himself and of his fellow-men, and to classify 
them without any reference to the similar- 
ity of purpose when the actions are similar. 
But as the study of Nature progressed, it 
was found to be quite futile to bring in the 
ideas of purpose and will when merely de- 
seribing and classifying the motions and 
changes of non-living matter. Purpose and 
will could be entirely left out of sight, and 
yet the observed motions and changes could 
be described, and predictions could be made 
as to future motions and changes. Limit- 
ing the aim of physical science to such de- 
scription and prediction, it gradually be- 
came clear that the method was adequate 
SCIENCE. 
387 
for the purpose, and over the range of non- 
living matter, at least, the psychical yielded 
to the physical. Laws ceased to be com- 
mands analogous to legal enactments, and 
became mere descriptions. But during the 
passage from one position to the other, by a 
confusion of thought which may appear 
strange to us now that we have finished the 
journey, though no doubt it was inevitable, 
the purpose and will of which the laws had 
been the expression were put into the laws 
themselves ; they were personified and made 
to will and act. 
Even now these early stages in the his- 
tory of thought can be traced by survivals 
in our language, survivals due to the ascrip- 
tion of moral qualities to matter. Thus 
gases are still sometimes said to obey or to 
disobey Boyle’s law as if it were an enact- 
ment for their guidance, and as if it set 
forth an ideal, the perfect gas, for their 
imitation. We still hear language which 
seems to imply that real gases are wanting 
in perfection, in that they fail to observe 
the exact letter of the law. I suppose on 
this view we should have to say that hydro- 
gen is nearest to perfection ; but then we 
should have to regard it as righteous over- 
much, a sort of Pharisee among gases which 
overshoots the mark in its endeavor to obey | 
the law. Oxygen and nitrogen we may re- 
gard as good enough in the affairs of every- 
day life. But carbon dioxide and chlorine 
and the like are poor sinners which yield 
to temptation and liquefy whenever cir- 
cumstances press at all hardly on them. 
There is a similar ascription of moral 
qualities when we judge bodies according 
to their fulfillment of the purpose for which 
we use them, when we describe them as 
good or bad radiators, good or bad insula- 
tors, as if it were a duty on their part to 
radiate well, or insulate well, and as if 
there were failures on the part of Nature 
to come up to the proper standard. 
These are of course mere trivialities, but 
