Newton's Conception of Absolute Space and Time
Absolute versus Relative: Newton’s own distinction
Newton made the distinction between absolute and relative space and time.
Relative space and time was that which could be observed and calculated by us. For example, duration could be measured with the aid of a clock and the distance from one object to another with a measuring tape.
Absolute space and time, on the other hand, are unobservable yet Newton remained certain that they had to exist.
Absolute space, in its own nature, without relation to anything external, remains always similar and immovable. Relative space is some movable dimension or measure of the absolute spaces, which our senses determine by its position to bodies and which is commonly taken for immovable space; such is the dimension of a subterraneous, an aerial, or celestial space, determined by its position in respect of the earth. Absolute and relative space are the same in figure and magnitude, but they do not remain always numerically the same. For if the earth, for instance, moves, a space of our air, which relatively and in respect of the earth remains always the same, will at one time be one part of the absolute space into which the air passes; at another time it will be another part of the same, and so, absolutely understood, it will be continually changed.
Empiricist versus Rationalist ???
Although Newton’s physical theories were widely acclaimed and highly successful, such assumption of absolutism as the basis of his theories proved too farfetched for many to accept. Newton was very empirical in his proceedings, however, when it came to space and time his practical side was forgotten and a different approach taken up. If he had remained true to his empirical side then he probably would never have postulated absolute space and time, its nature being something existing in and off itself that we cannot experience in and off itself.
Newton’s Reasoning for Absolute Space and Time
His main argument is constructed from the Bucket Experiment,
This was a somewhat simple experiment that produced surprising and mysterious results. Basically a bucket full of water was held suspended by a rope, which had been twisted around many times (11a). When the bucket was held stationary the water remained flat on the surface. Once the bucket was released however the water rose to the edges of the bucket forming a concave surface (11b). The idea was to use this as a thought experiment whereby the bucket, rope and water are all that exist. Since in both cases the bucket and water are at rest in relation to each other (both rotating around the same axis), there is no reason for the water to act in such a way unless it does so in relation to another force. Given that nothing else exists then there must be something absolute with respect to which it is spinning: absolute space.
The following is a description of absolute space and time given by Newton,
Absolute, true, and mathematical time, of itself and from its own nature,
flows equably without relation to anything external, and by another name is
called "duration"; relative, apparent, and common time is some sensible
and external (whether accurate or unequable) measure of duration by the means
of motion, which is commonly used instead of true time, such as an hour, a day,
a month, a year.
Features of Absolute Space and Time
Newton makes many points about absolute space and time, that they are homogenous, infinite, isotropic, object independent (therefore mind independent) and immutable to name but a few. Let us discuss a couple of these in order to have a basis for understanding Leibniz’s criticisms of absolute space and time and his own postulation of relational space and time,
Absolute Space and Time as Homogenous
Absolute Space, in its own nature, without relation to anything external, remains always similar and immovable.
No part of space or moment of time have an individual identity, all parts and moments are equivalent.
Absolute Space and Time as Object Independent
Although we can possibly imagine that there is nothing in space, yet we cannot think that space does not exist, just as we cannot think there is no duration, even though it would be possible to suppose that nothing itself endures.
Click here to view Leibniz's objections and own conception of Space and Time