Aristotle’s Physics Reviewed. 
173 
I pass over the proofs that the universe as a whole is finite in magnitude. 
In the Fourth Book we find the well known analysis of place as a relation 
existing between corporeal things, the relation of some actual finite body 
to its container. The universe, as a whole is therefore not in place. 
(III. 5.) 
IV. 8. What then, do we mean by space? It is merely the indefinite 
(apeiron) enlargement of the same idea, applied to the potential, not actual, 
extension of bodies with their three dimensions. In other words, space is 
no actualized entity, but the indefinite thought whose actuality is place 
as a relation in actual bodies. I do not see that in this we have made any 
advance from our author. Physical science can tell us whether w r e need 
anything more. 
IV. 8. Aristotle clearly sees and points out the relations of the prob¬ 
lem of the existence of a vacuum to this question of space, and denies its 
existence. Vacuum is unintelligible, it involves contradiction in thought; 
it contradicts experience. 
From this denial of a vacuum follows a mechanical theory of motion, 
(kinesis) which Aristotle intimates, but does not follow out, neither was 
any man then competent to do so. 
IV. 10. Motion and time are co-eval. There never was a time in which 
motion did not exist. Which brings us to a physical conception, as funda¬ 
mental as it is thoroughly established, and I believe, as fruitful as any in 
Aristotle’s physics. What is time? He proves that it is not an independ¬ 
ent entity. It is not change, which is particular, found in this or that. 
IV. 10. It is not motion, which is faster or slower; predicates which 
are not applicable to time. And yet it requires motion; i. e., change; and all 
things which are immoveable, unchangeable, are not in time. Time is con¬ 
tinuous; it is limited by what we call “now;” which is like amoving 
point describing a line. 
So we reach our definition; “ Time is the number of motion (change) in 
respect of prior and posterior.” This, of course, implies an intelligence to 
do the numbering. In a purely material universe there would be no such 
thing as time. (It may seem to us otherwise; but we put ourselves there 
to do the numbering.) 
IV. 11. Time is continuous, not an aggregate of instants or nows. 
IV. 12. A very plain deduction is that time is either finite, actually, 
or indefinite, potentially. But it can never be perfect (teleion) or what I 
should call the proper infinite. When limited by two nows, like, two 
points, e. g., one past and the other that moving point which we call the 
present, time is finite; disregarding either of the nows, we get the poten¬ 
tially infinite (apeiron) in duration. 
IV. 12. Things which are not in time (and such things there are), neither 
move nor rest. For rest is the privation of motion, and is numerable in Che 
same way. Those beings only are in time which are subject to motion, to 
change. 
