Reference: The Nature of the Physical World

This paper presents Chapter V (section 4) from the book THE NATURE OF THE PHYSICAL WORLD by A. S. EDDINGTON. The contents of this book are based on the lectures that Eddington delivered at the University of Edinburgh in January to March 1927.

The paragraphs of original material are accompanied by brief comments in color, based on the present understanding.  Feedback on these comments is appreciated.

The heading below links to the original materials.

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Our Dual Recognition of Time

Another curiosity which strikes us is the divorce in physics between time and time’s arrow. A being from another world who wishes to discover the temporal relation of two events in this world has to read two different indicators. He must read a clock in order to find out how much later one event is than the other, and he must read some arrangement for measuring the disorganisation of energy (e.g. a thermometer) in order to discover which event is the later. (To make the test strictly from another world he must not assume that the figures marked on the clock-dial necessarily go the right way round; nor must he assume that the progress of his consciousness has any relation to the flow of time in our world. He has, therefore, merely two dial-readings for the two events without knowing whether the difference should be reckoned plus or minus. The thermometer would be used in conjunction with a hot and cold body in contact. The difference of the thermometer readings for the two bodies would be taken at the moment of each event. The event for which the difference is smaller is the later.) The division of labour is especially striking when we remember that our best clocks are those in which all processes such as friction, which introduce disorganisation of energy, are eliminated as far as possible. The more perfect the instrument as a measurer of time, the more completely does it conceal time’s arrow.

The level of quantization of substance determines its duration and thus, its time characteristics. The temporal relation between two objects shall then be determined by the difference between their levels of quantization.

Time’s arrow provides the direction of the sequence in which changes take place. The temporal relation between two objects shall then also be determined their relative position in the sequence of changes.

This paradox seems to be explained by the fact pointed out in chapter III that time comes into our consciousness by two routes. We picture the mind like an editor in his sanctum receiving through the nerves scrappy messages from all over the outside world, and making a story of them with, I fear, a good deal of editorial invention. Like other physical quantities time enters in that way as a particular measurable relation between events in the outside world; but it comes in without its arrow. In addition our editor himself experiences a time in his consciousness—the temporal relation along his own track through the world. This experience is immediate, not a message from outside, but the editor realises that what he is experiencing is equivalent to the time described in the messages. Now consciousness declares that this private time possesses an arrow, and so gives a hint to search further for the missing arrow among the messages. The curious thing is that, although the arrow is ultimately found among the messages from outside, it is not found in the messages from clocks, but in messages from thermometers and the like instruments which do not ordinarily pretend to measure time.

The paradox arises because Eddington is determining time through physical means and also directly through mental intuition. How these two methods relate to each other is not described.

Consciousness, besides detecting time’s arrow, also roughly measures the passage of time. It has the right idea of time-measurement, but is a bit of a bungler in carrying it out. Our consciousness somehow manages to keep in close touch with the material world, and we must suppose that its record of the flight of time is the reading of some kind of a clock in the material of the brain—possibly a clock which is a rather bad timekeeper. I have generally had in mind in this connection an analogy with the clocks of physics designed for good time-keeping; but I am now inclined to think that a better analogy would be an entropy-clock, i.e. an instrument designed primarily for measuring the rate of disorganisation of energy, and only very roughly keeping pace with time.

Consciousness has not been described here scientifically. Also, the assumption that time can be measured by disorganization of energy, is unverified.

A typical entropy-clock might be designed as follows. An electric circuit is composed of two different metals with their two junctions embedded respectively in a hot and cold body in contact. The circuit contains a galvanometer which constitutes the dial of the entropy-clock. The thermoelectric current in the circuit is proportional to the difference of temperature of the two bodies; so that as the shuffling of energy between them proceeds, the temperature difference decreases and the galvanometer reading continually decreases. This clock will infallibly tell an observer from another world which of two events is the later. We have seen that no ordinary clock can do this. As to its time-keeping qualities we can only say that the motion of the galvanometer needle has some connection with the rate of passage of time—which is perhaps as much as can be said for the time-keeping qualities of consciousness.

It seems to me, therefore, that consciousness with its insistence on time’s arrow and its rather erratic ideas of time measurement may be guided by entropy-clocks in some portion of the brain. That avoids the unnatural assumption that we consult two different cells of the material brain in forming our ideas of duration and of becoming, respectively. Entropy-gradient is then the direct equivalent of the time of consciousness in both its aspects. Duration measured by physical clocks (time-like interval) is only remotely connected.

When entropy is increasing, the system is moving toward equilibrium. This means that the system is moving toward more settled organization, or increased quantization. Therefore, we may determine time by the level of quantization; and time’s arrow by the direction of increasing quantization.

Let us try to clear up our ideas of time by a summary of the position now reached. Firstly, physical time is a system of partitions in the four-dimensional world (world-wide instants). These are artificial and relative and by no means correspond to anything indicated to us by the time of consciousness. Secondly, we recognise in the relativity theory something called a temporal relation which is absolutely distinct from a spatial relation. One consequence of this distinction is that the mind attached to a material body can only traverse a temporal relation; so that, even if there is no closer connection, there is at least a one-to-one correspondence between the sequence of phases of the mind and a sequence of points in temporal relation. Since the mind interprets its own sequence as a time of consciousness, we can at least say that the temporal relation in physics has a connection with the time of consciousness which the spatial relation does not possess. I doubt if the connection is any closer. I do not think the mental sequence is a “reading off” of the physical temporal relation, because in physics the temporal relation is arrowless. I think it is a reading off of the physical entropy-gradient, since this has the necessary arrow. Temporal relation and entropy-gradient, both rigorously defined in physics, are entirely distinct and in general are not numerically related. But, of course, other things besides time can “keep time”; and there is no reason why the generation of the random element in a special locality of the brain should not proceed fairly uniformly. In that case there will not be too great a divergence between the passage of time in consciousness and the length of the corresponding temporal relation in the physical world.

The “four-dimensional world of space-time” actually provides the substantialness, or quantization, of the substance on an absolute (not relative) basis. Once we figure out the method to measure quantization, we can then determine both time and time’s arrow easily.

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 Reference: The Nature of the Physical World

This paper presents Chapter V (section 2) from the book THE NATURE OF THE PHYSICAL WORLD by A. S. EDDINGTON. The contents of this book are based on the lectures that Eddington delivered at the University of Edinburgh in January to March 1927.

The paragraphs of original material are accompanied by brief comments in color, based on the present understanding.  Feedback on these comments is appreciated.

The heading below links to the original materials.

.

Dynamic Quality of the External World

But for our ulterior conviction of the dynamic quality of time, it would be possible to take the view that ”becoming” is purely subjective—that there is no “becoming” in the external world which lies passively spread out in the time-dimension as Minkowski pictured it. My consciousness then invents its own serial order for the sense impressions belonging to the different view-points along the track in the external world, occupied by the four-dimensional worm who is in some mysterious way Myself; and in focussing the sensations of a particular view-point I get the illusion that the corresponding external events are “taking place”. I suppose that this would be adequate to account for the observed phenomena. The objections to it hinge on the fact that it leaves the external world without any dynamic quality intrinsic to it.

From the “continuum of substance” perspective the UNIVERSE is a single system that is intrinsically continuous, harmonious and consistent. Therefore, the essential criterion of objectivity is consistency, harmony and continuity among all observations.

Subjectivity is the degree to which one fails to observe the consistency, harmony and continuity of the universe. Thus, physical perceptions of the external world that are not consistent with each other are suffering from subjectivity. And mental perceptions that are consistent within themselves and with physical perceptions are objective.

Many believe that if a perception is mental then it must be subjective. This error comes from the “particles in void” perspective. The viewpoint of ‘time’ and ‘becoming’ is not necessarily subjective. It can be objective if it is consistent with surrounding observations.

It is useful to recognise how some of our most elementary reasoning tacitly assumes the existence of this dynamic quality or trend; to eradicate it would almost paralyse our faculties of inference. In the operation of shuffling cards it seems axiomatic that the cards must be in greater disarrangement at a later instant. Can you conceive Nature to be such that this is not obviously true? But what do we here mean by “later”? So far as the axiomatic character of the conclusion is concerned (not its experimental verification) we cannot mean “later” as judged by consciousness; its obviousness is not bound up with any speculations as to the behaviour of consciousness. Do we then mean “later” as judged by the physical criterion of time’s arrow, i.e. corresponding to a greater proportion of the random element? But that would be tautological—the cards are more disarranged when there is more of the random element. We did not mean a tautology; we unwittingly accepted as a basis for our thought about the question an unambiguous trend from past to future in the space-time where the operation of shuffling is performed.

It is an assumption that ‘later’ is always a greater proportion of random element. The random element is subjective because it is being viewed relative to some past condition. The concept of ‘later’ could be understood in terms of sequence of changes, or greater equilibrium.

The crux of the matter is that, although a change described as sorting is the exact opposite to a change described as shuffling we cannot imagine a cause of sorting to be the exact opposite of a cause of shuffling. Thus a reversal of the time-direction which turns shuffling into sorting does not make the appropriate transformation of their causes. Shuffling can have inorganic causes, but sorting is the prerogative of mind or instinct. We cannot believe that it is merely an orientation with respect to the time-direction which differentiates us from inorganic nature. Shuffling is related to sorting (so far as the change of configuration is concerned) as plus is to minus; but to say that the cause of shuffling is related to the cause of sorting in the same way would seem equivalent to saying that the activities of matter and mind are related like plus and minus—which surely is nonsense. Hence if we view the world from future to past so that shuffling and sorting are interchanged, their causes do not follow suit, and the rational connection is broken. To restore coherency we must postulate that by this change of direction something else has been reversed, viz. the trend in world-texture spoken of above; “becoming” has been turned into “unbecoming”. If we like we can now go on to account, not for things becoming unshuffled, but for their unbecoming shuffled—and, if we wish to pursue this aspect further, we must discuss not the causes but the un-causes. But, without tying ourselves into verbal knots, the meaning evidently is that “becoming” gives a texture to the world which it is illegitimate to reverse.

The direction of time is the direction of increasing equilibrium. Each condition has its own equilibrium organization. By changing the condition from A to B, we can trigger a sequence of changes. Then by changing the condition from B to A, we can reverse that sequence of changes. We may call this a reversal of local time per the definition above.

To reverse the universal time we must know the original condition that existed at the beginning of the universe. The universe must then be convinced to be in that original condition to establish the reversal of time.

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