Tempus absolutum, quod aequabiliter fluit. – Newton
According to Galilean and Newtonian mechanics, time is an absolute. The time that Newton describes is a general and universal time – tempus
absolutum, quod aequabiliter fluit ("absolute time which flows at an even
pace"). According to Kant, time has no absolute reality, neither subsistent nor inherent. As a subsistent reality, time exists only in the myth, where Kronos unsexes his father with a diamond scythe, or in the heads of people who make time, the non-thing, into a thing. Nor does time have a reality inherent in things. Since time is an a priori concept, the connection between time and things is cut; experience cannot gain admittance. Kant uses his premise that the concept of time is given a priori to deny it absolute reality, either subsistent or inherent.
This time, which neither represents anything in itself when I subtract objects from it, nor is inherent in things, is therefore an ideological concept, a form without content, an intellectual pattern. This pattern is not like an empty box or, as has been said, an empty apartment house. It can be likened to the emptiness of a box – without the box. If, then, time is not inherent in things one must conclude that all the dying, wilting, withering has in reality nothing to do with time, and that the language of all peoples, as it expresses the inherence of time in things through countless words, idioms, phrases and proverbs, is on the wrong track. According to Kant, holidays are contained in time, but time is not contained in holidays. Rhythm is in time, but time is not in rhythm. It follows that all this being born and dying, all this movement remains outside of time, time is merely an idea, an intellectual pattern which has nothing to do with things. For what have life and death, what has all this movement to do with time in that case? Even though Kant denies the absolute reality of time which Newton asserted, he does agree with Newton on other properties of time. He, too, has the notion of a single, universal, infinite, and infinitely divisible time that is irreversible and cannot be measured by itself but only by the time-space movements of bodies. Here, time always equals time. The relation of time particles is quantitatively measurable, but all these particles are alike in quality and
form. And these time particles, if they are not simultaneous, flow along in a steady stream like channeled molecules, but without being molecular by their nature. Or one could liken them to a reel which rolls off from infinity to infinity with unchanging, uniform speed. Kant's concept of time betrays that it was influenced and shaped by Galilean and Newtonian mechanics. Thereby it has become somewhat mechanical itself. For obviously, time is here understood as something lifeless, something rigid. And indeed, he who reads Newton's fundamental dicta on the nature of time receives an impression of death's majesty and of eternity's awe.
Newton accords absolute reality to this linear, uninterrupted motion by which time rolls on inexorably. According to Kant, it is merely an intellectual construction, in which alone it has existence. Time, Kant states, determines "the relation of ideas in our inner state. And just because this inner vision takes no physical shape, we try to make up for this lack through analogies, and represent the sequence of time as a line going into the infinite, a line which reduces all things in a row to one dimension only. From the properties of this line we then conclude all the properties of time, with the sole exception that the parts of the line exist simultaneously, whereas the parts of time always follow one after the other.”
However, there is still another reason for this linear concept of time. The concept is due to the fact that space and time are here understood as completely unrelated to each other. Neither space-times nor time-spaces are considered as existing. Linear time passes through space, without touching it; space stretches in a like manner through time. If this strict separation of time and space is accepted, then the linear concept of time remains, indeed, the one most intelligible and most convincing, since a uniform and undisturbed flow of time can only be imagined as a line. We mention this in view of those modern theories of physics in which this separation is replaced by an indissoluble union between time and space – a concept that leads to quite a different interpretation of the universe.
To most people it is immediately convincing that there should be a single, infinite, and infinitely divisible time. Perhaps this is because it is analogous
to a single, infinite, and infinitely divisible space; perhaps, too, because this concept reduces everything to the simplest formula. Could it be that there are two, several, or an infinite number of times? If time is inherent in things in such a manner that the nature of the thing affects time, or the nature of time affects the thing, does it not follow that there must be an infinite number of times? Apart from the relations between things, must not there also be relations between times which are distinguished not only quantitatively by measurement, but qualitatively, according to their structure?
Only so long as our theoretical perceptions remain limited to the field of the mathematical and physical sciences can we content ourselves with a mechanical definition of time. But if we break through these limitations, can such mechanical definitions continue to satisfy us? Can we then content ourselves with such statements as, for instance, that time exists a priori and is to be imagined as a line? Or that speed, within the same space, is in the inverse ratio of time? Here arises the question of the role which is played by our measuring methods, for we not only regulate time by means of clocks; these clocks in turn regulate our time. These two processes of measuring differ. When we study the relationship between them, it becomes clear that the measuring of time and its particles by means of timepieces that record the mechanical flow of time does not exist for its own sake. Rather, it is tied closely to the second measuring process whereby our timepieces regulate our time. This deadlock is by no means broken if we assume that a recurrent event in nature requires always the same amount of time. Instruments based upon recurrent natural events have been designed, such as the quartz clock. By such instruments time measurements can indeed be made independent from the rotation of the earth, the uniformity of which is doubtful. But the question still remains whether there are any uniform repetitions at all, whether in all nature there could be found two events which are exactly alike and different only in the moment of their occurrence.
We shall not dwell upon this question which is only of theoretical interest here. We have pointed to it merely to show what counts in the measuring of time by instruments, namely, the mechanically precise phase duplication of
whatever the physics are upon which the method is based. The supposition remains that time equals time. If it is accepted, then the determination of the relation between the particles of time depends on the refinement of the methods that can yield constantly more exact measurements. In this measuring process the relation between absolute and empirical time is for the moment of no importance. From the assumption of an absolute time in the sense of Galilean and Newtonian mechanics, and especially from Newton's definition of time, the conclusion is that time, while it is being moved, does not move itself or change itself. It moves like a machine, that is, it works like an automaton.
For if time moved and changed itself, then it could not "flow at an even pace," as Newton states. Without this assumption there could be no timepieces, for they all depend on the existence of uniform repetition. For the practical purposes of time measurement, it does not make the slightest difference whether we ascribe to time an absolute reality, or whether we consider it a transcendental ideal and an empirical reality. All these definitions, no matter how conflicting in ideology, remain without influence upon time-measuring methods. Improvement of those methods goes on regardless of theoretical disputes.