ae 
1903.] STONEY—UNIVERSE OF REAL EXISTENCES. 127 
motions of a great machine and the movements amongst the shad- 
ows which the parts of the machine cast when the sun shines. If 
the machine moves in an orderly manner, so also will the shadows 
move in an orderly manner; and Natural Science is the study of 
these movements amongst the shadows. If we had adequate access 
to the machine, the best way to investigate the movements of the 
shadows would be to study what takes place in the machine, and from 
it to forecast what must happen among the shadows. But, unfortu- 
nately, though we can see the shadows, we can bring only an exces- 
sively small part of the machine under close inspection, and we have 
but glimpses of the rest. The only part of the stupendous autic uni- 
verse which a human being can adeguate/y examine is that exces- 
sively small group of auta which are the thoughts of his own mind, 
with the similarly small groups that are the minds of his fellow- 
men and of some other animals: he cannot even make any ade- 
quate study of the events that go on within the synergos which is so 
closely associated with his mind, and can only collect mere scraps 
of information as to what the real events are throughout the rest of 
the vast machine.. As to that tiny group of auta that are one human 
being’s thoughts, it bears somewhat the same relation to the mighty 
whole of the autic universe as their protheton, namely, some of the 
more slowly changing events within the cortex of his brain, bears to 
the enormous totality of motions that are going on objectively 
throughout the whole of nature. This makes it evident that the part 
of the autic universe that man can adequately examine is but one 
drop of an immeasurable ocean, and although that little drop is an 
actual specimen of the kind of things that auta are, it is very plain 
that we are not justified in assuming that it is a fair average speci- 
men of them. 
Working under these disadvantages, man (and the same is true of 
the more intelligent of the lower animals) has constructed the Physz- 
cal Hypothesis whereby to enable him to form a correct forecast of 
the changes which will occur in nature. The physical hypothesis is 
the supposition shat the objects of nature can act on one another, either 
directly (action at a distance) or through intervening media (which 
by many is supposed to be an essentially different kind of action). 
Now the objects of nature are syntheta of perceptions and ultra- 
perceptions (as appears from the last chapter read along with those 
which follow) ; and syntheta of perceptions cannot be what really 
act. Nevertheless, it is eminently useful to carry on our investiga- 
