Perhaps the duration between instants x and y could be. However, the log metric does not have this property. Our civilization designs a clock to count up to higher numbers rather than down to lower numbers as time elapses. Is that a convention? In fact, when Westerners talk about past centuries, they agree to use both A.
A clock measuring B. The laws of physics involving time t are unchanged regardless of whether the t is measured in B. The clock on today's wall always counts up, but that is merely because it is agreed we are in the A. Choice of the origin of the time coordinate is conventional, too. It might be a Muhammed event or a Jesus event or a Temple event or the big bang event.
It is an interesting fact and not a convention that our universe is even capable of having a standard clock that measures both electromagnetic events and gravitational events and that "electromagnetic time" stays in synchrony with "gravitational time. It is a fact and not a convention that our universe contains a wide variety of phenomena that are sufficiently regular in their ticking to serve as clocks.
They are sufficiently regular because they tick in adequate synchrony with the standard clock. The word "adequate" here means successful for the purposes we have for using a clock, for example for measuring lifetimes of mountain ranges or, by using a very different kind of clock, for measuring the very brief duration of a photon interacting with another photon.
Relativity theory and quantum theory imply time is continuous. So, physicists regularly use the concept of a point of continuous time.
- Philosophy of Economics.
- Haunted Douglas County, Colorado: The Haunted Locations of Aurora, Castle Rock, Highlands Ranch and Parker.
- Contact information of Springer!
They might say some event happened the square root of three seconds after another event. Physicists usually uncritically accept a point of time as being real, but philosophers of physics disagree with each other about whether the points of time are real or, instead, merely useful. Is time's being a continuum a fact or just a convention that should be eliminated in a better treatment of time?
Our society's standard clock tells everyone what time it really is. Can our standard clock be inaccurate? Yes, say the objectivists about the standard clock. No, say the conventionalists who claim the standard clock is accurate by convention; if it acts strangely, then all other clocks must act equally strangely in order to stay in synchrony with the standard clock.
- Developing ‘process pragmatism’ to underpin engaged research in human geography!
- Mathematik und Wirklichkeit - Von den Wurzeln der Mathematik zu einer Didaktik des Sachrechnens (German Edition)!
- Just Doing My Job: Cops, firies, ambos. Everyday Australians with extraordinary stories..
- Find a copy online!
For an example of strangeness, suppose our standard clock used the periodic rotations of the Earth relative to the background stars. In that case, if a comet struck Earth and affected the rotational speed of the Earth as judged by, say, a pendulum clock , then we would be forced to say the rotation speed of the Earth did not really change but rather the other periodic clock-like phenomena such as swinging pendulums and quartz crystal oscillations all changed in unison because of the comet strike. The comet "broke" those clocks. That would be a strange conclusion to draw, and in fact for just this reason, physicists have rejected any standard clock that is based on Earth rotations and chosen a newer standard clock that is based on atomic phenomena that are unaffected by comet strikes.
A closely related philosophical question about choice of standard clock is whether, when we change our standard clock, we are merely adopting constitutive conventions for our convenience, or in some objective sense we can be making a choice that is closer to being correct. For more on this point, see this article's Supplement.
It would be very helpful in doing physics if there were a convention to adopt that allows for a single reference frame in which any two events are forced either to be simultaneous or to be such that one of them happens before the other. In general relativity theory applied to our universe, simultaneity does not make sense globally even though it always does make sense in any infinitesimally small region; these are small enough regions so that the special theory of relativity is true.
Nevertheless, if the convention is adopted of using a very special coordinate system, then sense can be made of a convention that fixes the time of any event globally. This special coordinate system needs to be very curvilinear as opposed to rectilinear and to be "patched" in analogy to a quilt made of patches of cloth.
Falvey Memorial Library :: Philosophy
Geodesics in spacetime are the free-fall world lines. The bumps are due to curvature associated with the presence of matter and energy. Using one of these special coordinate systems, all the events in each, single sheet throughout the universe happen simultaneously. This sort of reference system is usually adopted by cosmologists for their convenience. Among the possible patchwork of frames one might adopt, some are much more useful choices than others. In particular, it is a useful convention to fix the spatial origin at a place where the light which has now turned to heat generated by the big bang arrives to Earth with about the same intensity and temperature from all directions.
As Davies , pp. In fact, it isn't quite true that the cosmic background heat radiation is completely uniform across the sky. It is very slightly hotter i. Although the view from Earth is of a slightly skewed cosmic heat bath, there must exist a motion, a frame of reference, which would make the bath appear exactly the same in every direction.
It would in fact seem perfectly uniform from an imaginary spacecraft traveling at km per second in a direction away from Leo towards Pisces, as it happens …. We can use this special clock to define a cosmic time…. Fortunately, the Earth is moving at only km per second relative to this hypothetical special clock.
- Library-Bibliographical Classification (LBC).
- Theory and Decision Library C, Springer | IDEAS/RePEc;
- GEOGRAPHY'S SPATIAL PERSPECTIVE AND THE PHILOSOPHY OF ERNST CASSIRER.
- Theory and Decision Library A:.
- Die Pferdeflüsterin erzählt (German Edition).
- Philosophy in Geography - Google книги.
- Philosophy of Climate Science Part II: Modelling Climate Change;
This is about 0. Similar hypothetical clocks could be located everywhere in the universe, in each case in a reference frame where the cosmic background heat radiation looks uniform. Notice I say "hypothetical"; we can imagine the clocks out there, and legions of sentient beings dutifully inspecting them. This set of imaginary observers will agree on a common time scale and a common set of dates for major events in the universe, even though they are moving relative to each other as a result of the general expansion of the universe So, cosmic time as measured by this special set of observers constitutes a type of universal time Time is both cosmic and not cosmic.
Although time is not cosmic that is, universal because which pairs of events throughout the cosmos are simultaneous is different in different frames, time also is cosmic in another sense, the sense in which there exists a special set of reference frames in which there would be universal agreement for stationary observers in those frames about the dates of major events of cosmic history. It is a convention that cosmologists agree to use the cosmic time of these special reference frames, but it is a fact and not a convention that the universe is so organized that there is such a useful cosmic time available to be adopted by the cosmologists.
Distant simultaneity is conventional. Or so Einsten claimed. The conventionality of simultaneity is not the same thing as the relativity of simultaneity. The philosophers B. Ellis and P. Bowman in , and D. Malament in , gave different reasons why Einstein and Reichenbach are mistaken about the conventionality of simultaneity. For an introduction to this dispute, see the Frequently Asked Questions.
For more discussion, see Callender and Hoefer We can see a clock, but we cannot see time, so how do we know whether time is real? Someone might think that time is real, that is, time exists, because it is what clocks are designed to measure, and because there certainly are clocks.
The trouble with this reasoning is that it is too analogous to saying that unicorns are real because unicorn hunters intend to find unicorns, and because there certainly are unicorn hunters. The logical positivist Rudolf Carnap said, "The external questions of the reality of physical space and physical time are pseudo-questions" "Empiricism, Semantics, and Ontology," He meant these two questions are meaningless because there is no way to empirically verify their answers one way or the other. Subsequent philosophers have generally disagreed with Carnap and have taken these metaphysical questions seriously.
Some philosophers and physicists claim there are other reasons to believe time itself is not real.
Theory and Decision Library A:
These reasons are that time is unreal because i it is emergent, or ii it is subjective, or iii it is merely conventional, or iv it is denoted by an inconsistent concept, or v its scientific image deviates too much from its commonsense image. All these reasons are explored below, in order. Some philosophers of time argue that an emergent time is therefore not a real time. Similarly, some metaphysicians such as Arthur Eddington and Peter van Inwagen have argued that tables and chairs are not real because they emerge from arrangements of elementary particles, and it is only these particles and their arrangements that are real.
The analogous position in the philosophy of mind is called "eliminative materialism. Does this imply time is not real? Most scientists and philosophers of time will answer "no" for the following reasons. Scientists once were surprised to learn that heat emerges from the motion of molecules, and that a molecule itself has no heat. Would it not have been a mistake to conclude from this that heat is unreal? And when it became clear that baseballs are basically a collection of atoms, and so baseballs can be said to emerge from atoms, would it not have been a mistake to say baseballs no longer exist?
The concept of time is already known to be so extremely useful at the larger scales, the scales of quarks and molecules and mountains and galaxies, that it must be said to be real at least at these scales. The compatibility of time not existing below the Planck level with time existing at a higher level of description is somewhat analogous to the compatibility of free will not existing at the level of molecular activity with free will existing at the macro-level of describing human behavior. An additional argument sometimes offered in support of this affirmation of emergent time draws attention to the question of how there could be observational support for a theory that time does not exist since presumably observations occur in time, and causal reasoning requires that causes occur before their effects.
Perhaps observations and causality could be explained with a timeless theory, but it is not at all clear how this could be accomplished.
Psychological time is clearly subjective, but the focus now is on physical time. Well, first what does "subjective" mean? This is a notoriously controversial term in philosophy. Here it means that a phenomenon is subjective if it is a mind-dependent phenomenon, something that depends upon being represented by a mind. A secondary quality such as "being red" is a subjective quality; being capable of reflecting light of a certain wavelength is not subjective. The point can be made by asking whether time comes just from us or instead is wholly out there in the external world independent of us.