"Such a view of the universe is inseparable from a mechanical determinism in which the future is unalterably determined by the past and in which the past can be uniquely inferred from the present state of the universe. It is the view of an intelligence which could comprehend at one glance the whole of time and space." [4]It is not surprising also that this spatialization of time lead to the belief that time-travel into the past was possible. In a essay Kurt Godel seriously suggested the Wellsian idea of a round trip "into any region of the past, present and future and back again" was possible. [5] In H. G. Wells' famous novel, The Time Machine, a fictitious traveler moves along the "fourth dimension" as freely as along the three spatial dimensions. Ernst Cassirer seems to support this concept when he claimed that in the theory of relativity the anisotropy of time disappears and that the distinction between the "past" and "future" is purely conventional, comparable to the difference between "plus" and "minus" signs in space. [6]
There were some important dissenting voices to this spatialization of time, both among the physicists and philosophers. Paul Langevin was one of the first who protested against calling time "the fourth dimension of space". [7] Einstein himself admitted that the asymmetry of time is preserved even in its relativistic union with space when he recognized that "we cannot send wire-messages into the past." When Meyerson in the session of the French Philosophical Society of April 6, 1922, insisted on the distinction of space from time even in the theory of relativity, and Einstein, who attended the session, explicitly agreed. Meyerson's argument was fully developed in his book, La Deduction relativiste, and Einstein in his highly favorable comment about it again praised Meyerson's criticism of spatialization of time. According to Einstein, the spatialization of time is a misinterpretation of the theory of relativity, a misinterpretation committed not only by popularizers, but even by many scientists, though it is often present in their mind implicitly. [8] In the 1920's, Eddington, Bridgman, and G. N. Lewis among the physicists and Whitehead, Bergson, and Reichenbach among the philosophers gave similar warnings. [9]
Whence this misinterpretation of space-time as the spatialization of time?
The answer to this question is to be found in that presistent tradition of
ancient Greek philosophy that may be called the Eleatic tradition.
Although Parmenides and his immediate successors remained isolated in their
radical and extreme denial of change and succession, they were followed by many
philosophers in their insistence that ultimate reality is timeless, and that
change and succession belong only to the realm of shadowy and changing
appearance. This belief in a dualism between changeless, timeless ultimate
reality (Being) and the half-real realm of the becoming is common to Plato,
Plotinus, Augustine, the medieval philosopher-theologians, Spinoza, Kant,
Hegel, Bradley and McTaggart, to name but a few. Even Augustine interpreted
the Biblical doctrine of the Creator and His creation from within this
dualistic framework. And in his view of God's relation to His creation,
Augustine viewed God as embracing the whole history of the universe in one
timeless act of knowledge. God's knows all that is, not because He see all
human history, but because God has willed it to be what it is. Augustine
thus interpreted the Biblical doctrine of predistination as a determinism,
in which God has determined in eternity all the happenings in time.
This Eleatic tendency is still present not only in philosophers with idealistic leanings but also, though lest explicitly, among naturalistic minded philosophers and philosophically minded scientists. In this last group, as strange as it may seem, the Eleatic tradition that ultimate reality is timeless has taken a less conspicuous but in its implications an equally radical form of the spatialization of time. In the attempt to defend the immutable Parmenidean One, Zeno denied the reality of change and motion by reducing time to a geometrical, infinitely divisible line and thus as a spatial dimension time could not be real. The elimination of time and the spatialization of time are closely related, the latter being merely a more concrete form of the former.
But the spatialization of time took a more systematic form in the modern period with the development of analytical geometry and classical mechanics. Descartes, who is founder of analytical geometry and cofounder of classical mechanics, was only being consistent when he called time a "dimension" and when he followed the analogy between a geometrical point and an instant time to its logical, though ultimately absurd consequence. Descartes concluded that our world was being perpetually perishing and continually being recreated. Thus the divine creatio continua supplied the missing dynamical link joining durationless instants.
In analytical geometry, there was no conscious attempt to spatialize time in symbolizing time by the t-axis (as the independent variable). The dynamic and progressive character of time was being only symbolized by an ideal motion of the pointlike instant of time, the present, sliding along the time axis from the past to the future. But in contemplating these spatial diagram of the temporal process, it is easy to forget the underlying dynamic character of time. Any spatial symbol of time views time as completed, whereas real time is incomplete; the future has not yet happened. The spatial symbolism of time leads one to forget the essential difference of the juxtaposion of points in space and succession of instants of time and to reduce the difference between the past, the present, and the future to simply the difference of position along a line; the "past" events are symbolized by points to the left of the point representing the present, while "future" events lie to the right of the same point on the same already drawn "temporal axis". Thus the spatial diagram suggests the wrong idea that successive moments already coexist and their pastness and futurity is not genuine, but only "phenomenal" or "apparent".
From such a point of view, future events already exist, and what we call their future occurence is only an unimportant way of speaking, unavoidable for a finite human consciousness, but not for a superhuman intelligence free of human limitation. When Laplace spoke of such a superhuman intelligence, he was not referring to the Augustinian or Calvinistic God ("I have no need of that hypothesis"), but only of the impersonal order of nature in which the past, present, and future occurences are contained; but Laplace's strictly deterministic point of view was really not any different than the Augustinian and Calvinistic ideas of predistination, only with impersonal nature replacing a "personal" God. The spatialization of time goes hand in hand with this Laplacian determinism or more precisely, predeterminism. When Descartes and D'Alembert called duration "the fourth dimension" and when Lagrange characteristized mechanics as a "geometry of four dimensions," they were only preparing the way for the Laplacian view of reality, which really belongs to the same tradition as was the views of Parmenides and Spinoza. The universe with its whole history is conceived as a single infinite and timeless bloc, given at once. In this scheme, time itself, as Bergson observed, is reduced to "our incapacity to know everything at once." [10]
It it precisely by this presistent Eleactic tendency, poping up again in the spatialization of time, that the true meaning of the relativity theory has been distorted. Sometimes those who interpret relativistic space-time in the sense of the timeless four-dimensional entity are aware of their affinity with the Eleactic tradition. This was true of Kurt Godel, who sees in the theory of relativity a confirmation of the views of Parmenides, Kant, and McTaggart. [11] If this were true, the theory of relativity would be a continuation and even a culmination of the main tendency of classical physics which pushed the reality of time into the background. Then the Laplacian ideal of the elimination of time would be completely realized in the idea that all future events already exist on the already drawn fourth dimension of space. Though the word "space-time" is still used, the "time" component is a mere word; it stands for the static fourth dimension which in virtue of its completed character is something timeless, and in which there in no "before" and "after." Spinoza, who excluded succession from the attributes of the ultimate reality and who, more than a century before Laplace and Kant, reduced time to "confused and inadequate knowledge," would certainly have agreed. [12]
Kant deprived time of its objective ontological status and reduced it to a mere appearance, relegating it to the phenomenal world. This created an intolerable dualism between the realm of phenomena, occurring in time, and the realm of timeless noumena. This raised the epistemological problem: if true reality is timeless, then where does this illusion of the succession of time come from? The supposed spatialization of time by the theory of relativity as the fourth dimension of space-time is supposed to solve this problem. Since time is the fourth dimension of space, then time is the subjective apprehension of this dimension of space. But Kant drew a sharp line between space and time. Time has only one dimension, different times are not simultaneous, but successive. Space has three dimensions, and different spaces are not successive, but simultaneous. [13] Even though this distinction between space and time are compatiable with the relativistic concept of space-time, Kant treated space and time as forms of perceptibility which our minds imposed upon sensation. The "things in themselves" (or noumena) are non-spatial and non-temporal but in our apprenhension of them through the senses, our minds imposes upon them spatial and temporal order by the a priori or innate forms of sensibility. In Kant's words,
"...Things which we see are not by themselves what we see. ... They cannot, as phenomena, exist by themselves, but in us only. It remains completely unknown to us what the objects may be by themselves and apart from the receptivity of our senses. We know nothing but our manner of perceiving them, that manner being peculiar to us and not necessarily shared in by every being, though, no doubt by every human being." [14]Thus the Eleactic tradition reached its logical end in skepticism; knowledge of ultimate reality cannot be had by human beings. Time is phenomenal and not noumenal, that is, reality is timeless. Time has no genuine reality. So the Eleactic tradition seems to indicate.
But if time has no genuine reality, then why does it appear so real?
Only by abandoning the Eleactic tradition in philosophy and the
spatialization of time in the interpretation of the theory of relativity
can the genuine reality of time be recognized and acknowledge.
Is time really spatialized in the theory of relativity? It is not.
Only those interpreters who come retaining the classical habits of thought
allege that time is a dimension of space and its fourth dimension.
Only by abandoning the dualism of the Eleatic tradition can time in the
theory of relativity be correctly understood.
[3] E. Meyerson, La Deduction relativiste, pp. 98-101;
H. Weyl, Was ist Materie? (Berlin, 1924), pp. 82, 87.
[4] E. Cunningham, The Principle of Relativity
(Cambridge, 1914), p. 213.
[5] Kurt Godel, "A Remark about the Relationship between Relativity Theory
and Idealistic Philosophy"
in Albert Einstein, Philosopher-Scientist,
ed. by P. A. Schilpp (Evanston, 1949), p. 550.
[6] E. Cassirer, Zum Einstein'schen Relativistatstheorie
(Berlin, 1921), p. 119.
[7] P. Langevin, "L'aspect general della theorie de la relativite",
Bulletin Scientifique des etudiants de Paris, No. 2 (1922), p. 6;
Bulletin de la Societe francaise de philosophie, 6 avril 1922,
p. 112.
[8] E. Meyerson, op. cit., pp. 102-110;
A. Einstein, "A propos de la deduction relativiste de M.E. Myererson",
Review philosophique, Vol. CV (1928), p. 165.
[9] A. E. Eddington, Space, Time, Gravitation
(Cambridge, 1920), pp. 51-52.
P. W. Bridgman, The Logic of Modern Physics
(New York, Macmillan, 1948), p. 74.
G. N. Lewis, The Anatomy of Science
(Yale University Press, 1926), p. 81.
A. N. Whitehead, The Concept of Nature,
Chap. III, especially pp. 53-54; also p. 178.
H. Bergson, Duree et simultaneite
(2nd ed., 1923), particular Chap. VI.
H. Reichenbach, Die Philosophie der Raum-Zeit-Lehre, p. 134
English translation by Maria Reichenbach,
The Philosophy of Space & Time
(New York: Dover Publications, Inc., 1958), p. 112.
(concerning the static misinterpretation of hte "world" of Minkowski).
Eddington's view was misunderstood by Meyerson; the passage quoted by
Myerson (La Deduction relativiste, p. 100) represents the static
view which Eddington, as the context indicates, rejects. See also Eddington,
The Nature of the Physical World
(Cambridge, 1928), pp. 50-52, 55-58.
[10] H. Bergson, Creative Evolution, p. 45.
[11] K. Godel, loc. cit., p. 357.
[12] B. Spinoza, Ethics, II, prop. 44, corol. II,
"[things] must therefore be conceived without any relation to time,
but under a certain form of eternity."
Spinoza, Selection, edited by John Wild,
(New York, Chicago, Boston: Charles Scribner's Sons, 1930), p. 192.
[13] I. Kant, Critique of Pure Reason, p. 75.
[14] I. Kant, Critique of Pure Reason,
revised edition, translated by Max Muller,
(New York: The Macmillan Company, 1922), p. 34.