The special theory of relativity was one of the greatest achievements of science. It has revolutionised the way we look at the universe to such an extent that it has been compared with the discovery that the earth is round. Gigantic strides forward have been made possible by the fact that relativity established a far more accurate method of measurement than the old Newtonian laws it partially displaced. The philosophical question of time has, however, not been removed by Einstein’s theory of relativity. If anything, it is more acute than ever. That there is something subjective and even arbitrary in the measurement of time is evident, as we have already commented. But this does not lead to the conclusion that time is purely a subjective thing. Einstein’s entire life was spent in the pursuit of the objective laws of nature. The question is whether the laws of nature, including time, are the same for everyone, regardless of the place in which they are and the speed at which they are moving. On this question, Einstein vacillated. At times, he seemed to accept it, but elsewhere he rejected it.

The objective processes of nature are not determined by whether they are observed or not. They exist in and for themselves. The universe, and therefore time, existed before there were human beings to observe it, and will continue to exist long after there are no humans to concern themselves about it. The material universe is eternal, infinite, and constantly changing. However, in order that human minds may grasp the infinite universe, it is necessary to translate it into finite terms, to analyse and quantify it, so that it can become a reality for us. The way we observe the universe does not change it (unless it involves physical processes which interfere with what is being observed). But the way it appears to us can indeed change. From our standpoint, the earth appears to be at rest. But to an astronaut flying past our planet, it seems to be hurtling past him at a great speed. Einstein, who seems to have had a very dry sense of humour, apparently once asked an astonished ticket inspector: “What time does Oxford stop at this train?”

Einstein was determined to re-write the laws of physics in such a way that the predictions would always be correct, irrespective of the motions of different bodies, or the “points of view” which derive from them. From the standpoint of relativity, steady motion on a straight line is indistinguishable from being at rest. When two objects pass each other at a constant speed, it is equally possible to say that A is passing B, or that B is passing A. Thus, we arrive at the apparent contradiction that the earth is both at rest and moving at the same time. In the example of the astronaut, “it has to be simultaneously correct to say that the earth has great energy of motion and no energy and motion; the astronaut’s point of view is just as valid as the view of learned men on earth.”[39]

Although it seems straightforward, the measurement of time nevertheless presents a problem, because the rate of change of time must be compared to something else. If there is some absolute time, then this in turn must flow, and therefore must be measured against some other time, and so on ad infinitum. It is important to realise, however, that this problem presents itself only in relation to the measurement of time. The philosophical question of the nature of time itself does not enter into it. For the practical purposes of calculation and measurement, it is essential that a specific frame of reference be defined. We must know the position of the observer relative to the observed phenomena. Relativity theory shows that such statement as “at one and the same place” and “at one and the same time” are, in fact, meaningless.

The theory of relativity involves a contradiction. It implies that simultaneity is relative to a frame of axes. If one frame of axes is moving relative to another, then events that are simultaneous relative to the first are not simultaneous relative to the second, and vice versa. This fact, which flies in the face of common sense, has been experimentally demonstrated. Unfortunately, it can lend itself to an idealist interpretation of time, for instance, the assertion that there can be a variety of “presents”. Moreover, the future can be portrayed as things and processes “that come into being” as four-dimensional solids that have as earliest temporal cross section or “time slice”.

Unless this question is settled, all kinds of mistakes can be made: for example, the idea that the future already exists, and suddenly materialises in the “now”, as a submerged rock suddenly appears when a wave breaks over it. In point of fact, both the past and the future are combined in the present. The future is being-in-potential. The past is what has already been. The “now” is the unity of both. It is actual being as opposed to potential being. Precisely for this reason, it is usual to feel regret for the past and fear for the future, not vice versa. The feeling of regret flows from the realisation, corroborated by all human experience, that the past is lost forever, whereas the future is uncertain, consisting in a great number of potential states.

Benjamin Franklin (1706-90) once observed that there are only two things certain in this life – death and taxes, and the Germans have a proverb: “Man muss nur sterben” –”one only has to die,” meaning that everything else is optional. Of course, this is not actually true. Many more things are inevitable than death, or even taxes. Out of an infinitely large number of potential states, in practice we know that only a certain number are really possible. Out of these, fewer still are probable at a given moment. And of the latter, in the end, only one will actually arise. The exact way in which this process unfolds is precisely the task of the different sciences to uncover. But this task will prove to be impossible if we do not accept that events and processes unfold in time, and that time is an objective phenomenon which expresses the most fundamental fact of all forms of matter and energy – change.

The material world is in a constant state of change, and therefore it “is and is not”. This is the fundamental proposition of dialectics. Philosophers like the Anglo-American Alfred North Whitehead and the French intuitionist Henri Bergson believed that the flow of time was a metaphysical fact, which could only be grasped by non-scientific intuition. “Process philosophers” like these, despite their mystical overtones, at least are correct in saying that the future is open or indeterminate whereas the past is unchangeable, fixed and determinate. It is “congealed time”. On the other hand we have the “philosophers of the manifold” who maintain that future events may exist but not be connected in a sufficiently lawlike way with past events. Pursuing a philosophically incorrect view of time, we end up with sheer mysticism, as in the notion of the “multiverse” – an infinite number of “parallel” universes (if that is the right word, since they do not exist in space “as we know it”) existing simultaneously (if that is the right word, since they do not exist in time “as we know it”). Such is the confusion that arises from the idealist interpretation of relativity.

  1. Calder, N. Einstein’s Universe, p. 22.