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(iii) Newton was actually very concerned to find some way of understanding what time and length were, independently of the way they were measured. He therefore defined what he called “Absolute Space” and “Absolute Time”. Explain what he meant by this, and also explain the ‘Rotating Bucket’ thought experiment he used to demonstrate the existence of absolute space.
Absolute Time
For Newton, Absolute Time is in its own nature absolute, true, and mathematical, and it keeps on flowing without relation to anything external. Because Absolute Time is objective, it does not change, it remains true, and what is true can only be grasped by mathematics’ perfection, and not by the senses’ misrepresentations. In this way, Absolute Time contrasts Relative or Common Time, which Newton defines as “the measure of time’s duration according to motion.”4 In other words, we perceive the passage of time or the duration of Relative or Common Time in relation to planetary motions, which define for us time as an hour, a day, a month or a year. Because we are able only to grasp relative time in relation to motion of perceivable objects, we cannot grasp Absolute Time with our senses. Like Absolute Space, Absolute Time exists independently, imperceptibly, and can only be grasped mathematically.
Absolute Space
For Newton, Absolute Space is in its own nature always the same, immovable, and bears no relation to anything external, that is, it is related to nothing. He defines Absolute Space as a great void occupied by objects, but existing in itself and by itself, independently of objects. This means that Absolute Space exists even without objects, and that though it is independent of objects, it can affect objects, as he demonstrates in his Rotating Bucket experiment explained below. In this way, Absolute Space contrasts Relative Space, which Newton defines as a “movable dimension (subterraneous, aerial or celestial), or a measure of the absolute spaces”5 in relation to the position of bodies in respect to the earth. In other words, Newton’s Relative Space is always changing, is related to objects, and moves within Absolute Space. Newton believed Relative Spaces could be determined by studying translatory or linear motion, while Absolute Space could be determined by rotational motion.
Newton’s Rotating Bucket
Newton believed he could demonstrate the existence of absolute space by rotation, that is, by hanging and spinning
4 Stamp, Phillip. The Life and Work of Newton. 9. 5 Stamp, Phillip. Newton. Mechanics. 10-12.
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