SEPTEMBER 22, 1899.] 
fact that we make no attempt at a complete 
physical account and explanation of those 
actions which he takes to accomplish his 
purpose. We trace no lines of induction 
in the ether connecting him with his friends 
across the Channel, we seek no law of force 
under which he moves. In practice the 
strictest physicist abandons the physical 
view, and replaces it by the psychical. He 
admits the study of purpose as well as the 
study of motion. 
He has to admit that here his physical 
method of prediction fails. In physical ob- 
servations one set of measurements may 
lead to the prediction of the results of an- 
other set of measurements. The equations 
expressing the lawsimply different observa- 
tions with some definite relation between 
their results, and if we know one set of ob- 
servations and that definite relation we can 
predict the result of the other set. But if 
we take the psychical view of actions, we 
can only measure the actions. We have no 
independent means of studying and meas- 
uring the motions which preceded the 
actions, we can only estimate their value 
by the consequent actions. If we formed 
equations they would be mere identities 
with the same terms on either side. 
The consistent and persistent physicist, 
finding the door closed against him, finding 
that he has hardly a sphere of influence left 
to him in the psychical region, seeks to ap- 
ply his methods in another way, by assum- 
ing that if he knew all about the molecular 
positions and motions in the living matter, 
then the ordinary physical laws could be 
applied, and the physical conditions at any 
future time could be predicted. He would 
say, I suppose, with regard to the Channel 
passenger, that it is absurd to begin with 
the most complicated mechanism, and seek 
to give a physical account of that. Ife would 
urge that we should take some lower form of 
life where the structure and motions are sim- 
pler, and apply the physical methods to that. 
SCIENCE. 395 
Well, then, let us look for the physical 
explanation of any motion which we are 
entitled from its likeness to our own action 
to call a voluntary motion. Must we not 
own that even the very beginning of such 
explanation is as yet non-existent? It ap- 
pears to me that the assumption that our 
methods do apply, and that purely physical 
explanation will suffice to predict all mo- 
tions and changes, voluntary and involun- 
tary, is at present simply a gigantic extra- 
polation, which we should unhesitatingly 
reject if it were merely a case of ordinary 
physical investigation. The physicist when 
thus extending his range is ceasing to be a 
physicist, ceasing to be content with his 
descriptive methods in his intense desire to 
show that he is a physicist throughout. 
Of course we may describe the motions 
and changes of any type of matter after the 
event, and in a purely physical manner. 
And as Professor Ward has suggested, in 
a mostimportant contribution to this subject 
which he has made in his recently published 
Gifford Lectures,* where ordinary physical 
explanations fail to give an account of the 
motions, we might imagine some structure 
in the ether, and such stresses between the 
ether and matter that our physical expla- 
nations should still hold. But, as Professor 
Ward says, such ethereal constructions 
would present no warrant for their reality 
or consistency. Indeed they would be 
mere images in the surface of things to ac- 
count for what goes on in front of the sur- 
face, and would have no more reality than 
the images of objects in a glass. 
If we have full confidence in the descrip- 
tive method, as applied to living and non- 
living matter, it appears to me that up to the 
present it teaches us that while in non-liv- 
ing matter we can always find similarities, 
that, while each event is like other events, 
actual or imagined, in a living being there 
* *Naturalism and Agnosticism,’ The Gifford Lec- 
tures, 1896-98, Vol II., p. 71. 
