The nature of space and time is an important topic of metaphysics, “the branch of philosophy that deals with the first principles of things, including such concepts as being, substance, essence, time, space, cause, and identity” [Stevenson 2007, p.1765, headword metaphysics 1] because “space and time are what render a world out of the totality of entities that are parts of it” [Audi1999, p.564, head-word metaphysics]. It might be helpful to have a very brief look at philosophic definitions of time42. The following two quotes are taken from the introductions of the pertinent entries in two modern dictionaries of philosophy:
41A few concluding remarks concerning time in physics:
1. Quantum mechanics: contrary to a particle’s positionrand momentump, timet is not an observable, i.e. it is not associated with an operator describing a measurable physical quan-tity, cf. [Cohen-Tannoudjiet al. 1977, p.136, 139 & 215]. Time is merely a real number parameter.
2. Relativistic physics: space and time are merged but “space-time is something more intricate than three dimensions of space plus one dimension of time” [Hestenes1966, p.81].
3. Time is not necessarily a fundamental concept: “Zeit als solche kann nicht das letz-te Konzept in der Beschreibung der Natur sein. Zeit ist weder urspr¨unglich noch genau.
Sie ist eine Sch¨atzung [. . . ]. Sie ist ein sekund¨arer Begriff.” [Wheeler 1998, p.32], cf.
[Misneret al. 1973, p.1203–1212] and [Eisenhardt 2006, p.178–192, 200–224 & 272–
280] for further reading on the concept of pregeometry.
42It should be clear that this very brief look at philosophic definitions of time cannot represent – not even to some degree – a cultural history of the concept of time in philosophy. It merely collects a couple of philosophic ideas that are of linguistic interest, i.e. relevant for the main part of this paper.
Zeit, die nicht umkehrbare, nicht wiederholbare Abfolge des Gesche-hens, die als Vergangenheit, Gegenwart und Zukunft, am Entstehen und Vergehen der Dinge erlebt wird. Die philosophische Er¨orterung des Zeitbegriffs ist meist an den Begriff der Ver¨anderung gekoppelt, sei es in Form der Bewegung, der Prozessualit¨at oder der Entwicklung [Gaede 2007b, p.379, headwordZeit].
time, “a moving image of eternity” (Plato); “the number of move-ments in respect of the before and after”43 (Aristotle); “the Life of the Soul in movement as it passes from one stage of act or experience to another” (Plotinus); “a present of things past, memory, a present of things present, sight, and a present of things future, expectation”
(Augustine). These definitions, like all attempts to encapsulate the essence of time in some neat formula, are unhelpfully circular be-cause they employ temporal notions. Although time might be too basic to admit of definition, there still are many questions about time that philosophers have made some progress in answering by analy-sis both of how we ordinarily experience and talk about time, and of the deliverances of science, thereby clarifying and deepening our understanding of what time is [Audi1999, p.920, headword time].
It is conspicuous that in both dictionary entries above the circular definitions given are immediately commented on in an almost apologetic way (“Die philosophische Er¨orterung. . . ” and “These definitions. . . ”). This reflects well the elusiveness of the definiendum. The philosophic attempts to define time refer either to the chronological sequence of events (“Abfolge des Geschehens”, “number of move-ments”) or to the notion of motion (“moving image”, “number of movements”,
“Life of the Soul in movement”), which reinforces the etymological findings.
Aristotle’s definition refers explicitly to the topology of time (“in respect of the before and after”) and stresses the numerical aspect of time (“number of movements”). Plato’s reference to eternity stays enigmatic without taking his
43An alternative translation of “α%ιϑµoς κιν` ησεως κατ´ α τ` o π%´` oτ ε%oν κα`ι υστ ε%oν´ ” [Aristotle1987, p.212, Physics IV:11, 219b2 in the Greek original] would be: numbering of movement according to a before and an after.
theory of ideas into account44: the world as we perceive it is an image of the eternal and unmoving cosmos of ideas.
The definition in German introduces the element of time awareness by linking the modes past, present and future to subjective experience (“als Vergangenheit, Gegenwart und Zukunft [. . . ] erlebt wird”). Augustinegoes one step further by reducing the modes of time to present conciousness (past = present memory, present = sight45, future = present expectations). According to Immanuel Kant, the notion of time is not based on experience46 but represents ana priori form of intuition47, which makes experience possible in the first place. This concept of time is radically different from the everyday notion of the experience of time. It also contradicts the concept of time in physics. Physicists measure and model time, i.e. they base their findings on empirical experimental data.
Kant’s view and the view of modern physics cannot be reconciliated. Henning Genz, who wrote a 300-page book about time in physics, spends half a page on explaining why he does not take Kant’s view into account. He points out that Kant’s time and the time of modern physics are two different things:
Die Zeit, deren Grunds¨atze Kant a priori kennt, ist seine Zeit; wir wissen heute, daß die wirkliche Zeit manche apodiktisch gewissen Grunds¨atze nicht beachtet. Unter Zeit versteht Kant eine wirkliche Form der inneren Anschauung – also keinesfalls die Zeit, wie sie dieses Buch zum Gegenstand hat [Genz 1999, p.72, his italics].
Alfred N. Whitehead points out that “time and space are characteris-tics of nature which presuppose the scheme of extension” [Whitehead 1979, p.289]. He puts forward a theory of extension which sees temporal and spatial extensiveness as secondary, i.e. derived from the primary notion of extension:
44The following statement is based on [Gaede2007b, p.379], which refers to Plato’s dialogue Timaeus, a speculative treatise on the nature of the physical world.
45Cf. the discussion of one’s field of vision in the context of the spatio-temporal here-now above (p.14).
46“Die Zeit ist kein empirischer Begriff, der irgend von einer Erfahrung abgezogen worden”
Kantquoted in [P¨oppel 2000, p.14, Abbildung 2].
47“Die Zeit ist eine Vorstellung, die allen Anschauungen zum Grunde liegt. [. . . ] Die Zeit ist [. . . ] a priori gegeben. In ihr allein ist alle Wirklichkeit der Erscheinungen m¨oglich”Kant quoted in [P¨oppel2000, p.14, Abbildung 2].
The extensiveness of space is really the spatialization of extension;
and the extensiveness of time is really the temporalization of exten-sion. Physical time expresses the reflection of genetic divisibility into coordinate divisibility. [. . . ] But extension does not in itself deter-mine the special facts which are true respecting physical time and physical space [Whitehead 1979, p.289].
Extension and divisibility are certainly attributes that space and time share. If one introduces a term such as proto-space that refers to these two attributes, then both space (‘spatial space’) and time (‘temporal space’) can be seen as spatializations of proto-space. The difference between time and space is due to further attributes that are added. An important added attribute of time is its flowing48, but it should be noted that the passing49 of time is not undisputed in philosophy:
The most fundamental debate in the philosophy of time concerns the status of temporal becoming. Do events really pass from the future to the present and into the past, as tensed- or A-theorists (derived from McTaggart’s 190850, 192751 A-series of past, present, and fu-ture moments or events) [. . . ] have maintained? Or is the passage of time a myth and an illusion, as B-theorists (derived from McTag-gart’s B-series of events ordered by the relations earlier, later, and
48We cannot move freely (back and forth) in time but we can think and talk about temporally remote times by opening mental spaces, whose flexibility is unlimited.
49Tim Maudlin differentiates between the passage and the flow of time. He “defend[s]
the claim that the passage of time is an intrinsic asymmetry in the structure of space-time itself, an asymmetry that has no spatial counterpart and is metaphysically independent of the material contents of space-time” [Maudlin2002, p.237]. “Except in a metaphorical sense, time does not move or flow. Rivers flow and locomotives move. [. . . ] The direction of the flow or motion is dependent on the direction of the passage of time. Change and flow and motion all presuppose the passage of time, so the reality of change is bound up with the reality of time’s passage, but we will avoid saying that time itself changes or flows” [Maudlin2002, p.238].
50“McTaggart J E M (1908, 1934). ‘The unreality of time.’ Mind 18, 457–474. In Keeling S J (ed.),Philosophical studies. London: Edward & Arnold & Co. 110–134” [Oaklander2006, p.576].
51“McTaggart J E M (1927). ‘Time.’ In Broad C D (ed.) The nature of existence 2.
Cambridge: Cambridge University Press. [Reprinted 1968, Grosse Pointe, MI: Scholarly Press, 9–31.]” [Oaklander2006, p.576].
simultaneous) [. . . ] have maintained? [Oaklander 2006, p.574].
In religious contexts time is often associated with the notion ofeternity. The word can either refer to a limitless amount of time52or to the absence of time.53 In an article about time in Ancient Egyptian thought54 Jan Assmann points out: “Wenn eine Kultur ¨uberhaupt zu einem Ewigkeitsbegriff vorgedrungen ist, dann ist dieser zu beschreiben als die Negation der dominierenden Merkmale ihres Zeitbegriffs” [Assmann 1998, p.204/205]. His ensuing examples are summa-rized in table 2.1, which characterizes eternity as the negation of time.
Table 2.1: Eternity as the negation of time according toAssmann Zeit (dominierendes Merkmal) Ewigkeit (Negation von Zeit)
gerichteter Fluss Stillstand
Entfaltung punktartige Kopr¨asenz
Bindung an einen Zyklus der Wiederkehr Erl¨osung
Sph¨are des Werdens und Vergehens Sph¨are des Seins zugemessene Spanne, Begrenztheit unbegrenzte Duration
Einmaligkeit unendliche Wiederholbarkeit
52“All of time [. . . ]; infinite time, without a beginning or an end”[Stevenson2007, p.868, headwordeternity 2].
53“Timelessness; a state to which time has no application”[Stevenson2007, p.868, head-wordeternity 4].
54Among other things,Assmanndiscusses the intricate semantics of the Egyptian wordsdjet (d¯t)andneheh (nh. h. ), which have both been translated by the words time and eternity, although neither of these translations really fits: djet and neheh “sind nicht, wie [unser Zeitbegriff], gegen eine Ewigkeit begrifflich abgegrenzt. Sie ufern, sozusagen, in Richtung auf das aus, was man unter Ewigkeit verstehen, was man jedenfalls nicht mehr Zeit nennen kann. Wichtig ist, daß dem ¨Agypter diese Unterscheidung ¨uberhaupt fremd war. F¨ur ihn gibt es kein
”Jenseits der Zeit“. Der ¨Ubergang vom Diesseits zum Jenseits liegt innerhalb der Zeit” [Assmann1998, p.202/203]. According toAssmann, the generic termtime is not lexically realised in Ancient Egyptian. He suggests the hendiadys neheh-and-djet as a possible translation of time, cf.
[Assmann1998, p.201]. The author posits that the core meaning of djet is the resultative aspect of time, whereas the core meaning ofneheh is the virtual aspect of time. According to Assmann, the Egyptian opposition resultative vs.virtual can be derived from the aspectual opposition perfective vs. imperfective, which represents the base of the temporal systems of Semito-Hamitic languages, cf. [Assmann1998, p.199].
A concept related but not identical to eternity is that of eternal present. In Christian mysticism55 the terms nunc fluens vs. nunc stans (elapsing now vs.
stationary now) are used, cf. the following quote ascribed to Anicius Manlius Severinus Boethius (480-524 or 525)56: nunc fluens facit tempus, nunc stans facit aeternitatem ‘The passing now makes time, the standing now makes eternity’. The stationary now can be seen as a phenomenon that is concomi-tant with certain states of consciousness. In a deep meditative state one might transcend time, i.e. perceive it as standing still.