Monday, April 15, 2013

The Nature of Time, Science and Economics

This is a post that delves into many non-economic subjects, so skip it if you find science and philosophy tedious!

I. Time and the Future in Economic Life
The future and the nature of time have a fundamental role to play in economics. I will briefly sketch the Post Keynesian view. In a highly complex system that is open like a human economic system, where specific variables are determined by possibly millions of decentralised decisions, where there is both endogenous and exogenous change, and complex negative and positive feedback, it is the case that fundamental uncertainty will be faced about some specific future values of relevant variables.

Fundamental uncertainty means that calculable, objective numeric probabilities are not possible about many specific future values of variables in the system subject to the processes described above (that is, you cannot calculate an objective probability like the a priori probability of rolling a 6 in a fair game of dice for future values of variables).

The future is seen as open and not predetermined (Dunn 2008: 106). Human agents have a role in inventing and creating the future by their actions and decisions (Dunn 2008: 106).

It is obvious that there are both stated concepts and unstated ontological assumptions here, which are as follows:
(1) a real thing called time that passes, or dynamic time;
(2) a moving present and dynamic world;
(3) a future that appears to be (but perhaps not necessarily is) not yet existent;
(4) a future that is not predetermined in an unalterable way, but is created by contingent human action.
The notions of time and the future are fundamental. But what does science say about these things?

II. The Scientific Theories of Time
We have three main theories of the nature of time:
(1) Presentism
This is the view that only the present – that is, the present instantaneous world – exists. Only the present has real existence. The past and future are unreal. Reality is the three dimensional spatial world with its dynamic time element, or (depending on one’s view) the human perception of it.

(2) the Growing block Universe
The Growing block universe theory assumes that only the past and present are real. But the past is “lifeless and inactive” and consciousness and the “flow of time” are only active in the present. To some extent, the Growing block universe appears to be a variant of Presentism. It is also called the “Crystallizing Block Universe” or “Emergent Block Universe” theory.

(3) Eternalism
This is the view that all events, things and objects (including people and living things) in the past and future have real existence. Past, present and future are all equally real. For some reason, human beings have the perception of a “moving present.”
It is obvious that “Presentism” is what seems to be the intuitively correct and commonsensical view of time, although the “Growing block universe” is also compatible, even if somewhat counterintuitive in its belief that the past has a kind of real existence.

Certainly, the view of uncertainty in Post Keynesian economics and of the unknowable future seem consistent with, and perhaps necessitate, a “Presentist” or “Growing block universe” view of time: only the present (and possibly the past) exists, and the future does not. The future is created, as time passes. In economic life, human choice has a causal role in shaping one of many possible futures.

The trouble is that many mainstream physicists think that the Eternalist view is true.

And the issue goes much deeper than just interesting consequences of Einstein’s theories of relativity. Briefly, Einstein showed that the amount of time that elapses for an object is dependent on both its velocity and/or its interaction with gravitational fields. If, for example, one accelerates to close to the speed of light, time slows down (that is, “time dilation” occurs), and one is projected forwards in time relative to other objects travelling at a lower velocity, simply because physical and chemical processes slow down as velocity increases. From this, it follows that absolute Newtonian time is ultimately unreal. Or perhaps what Newton imagined as absolute time can only be strictly limited to spaces and objects with homogenous or near homogenous velocities or gravitational fields.

But the mainstream view of time is more radical than these findings from relativity theory, though certainly partly derived from them. What is asserted is this: the universe is thought to be a four-dimensional block or “block universe,” containing everything from the Big Bang to the end of the universe and all things that have ever existed or will ever exist. The forward direction or “arrow” of time is illusory because the whole universe is ultimately static, and if one could view it from “outside,” there is no point anywhere in the universe that can be objectively called the present.

Perhaps you think I exaggerate? Just observe the respected physicist Paul Davies proclaim that the flow of time is an illusion (Davies 2002). A strident statement of the same ideas can be found in Julian B. Barbour’s The End of Time: The Next Revolution in Our Understanding of the Universe (New York, 2000).

According to these ideas, the universe is ultimately timeless and static.

Pushed to its limit, a consequence of this theory is that the “block universe” is eternal and had no actual beginning in time, no subsequent development or growth, and no end, for that would require that there was in fact once a moving present, and would imply “Presentism” or the “Growing block universe” view.

If it is true that the universe is eternal, what sense is there in talking of the Big Bang as the causal origin of the universe or of subsequent causal developments and evolution of the universe? Or of an end? Such talk is inaccurate and actually appears unjustified and untrue, if the universe was eternal, timeless and not, strictly speaking, the creation of an unfolding present from a beginning at the Big Bang.

III. The Consequences of Eternalism
Under the Eternalist view, the “block universe” just is, always was, and always will be. Like the traditional god of Western theism, the “block universe” is just eternal and (possibly) uncreated.

What does the Eternalist “block universe” theory of reality entail about human consciousness, decision-making and existence?

First, it appears to deny free will. How is our vision of an economic future created by conscious human choice that is real and contingent and that could have been different consistent with the “block universe”? It seems utterly inconsistent. The perception of free will and real choice in action are illusions. The future is written already.

The second question is this: what is a conscious human mind under the Eternalist view? I digress at length on this point.

Our mind appears to be an entity extended in the “block universe.” But the “block universe” is normally thought of as a timeless, static and unchanging entity. How can humans have a conscious perception of a dynamic universe changing in a moving present?

One answer offered is that all moments of conscious life are equally real. The mathematician Rudolf von Bitter Rucker puts it this way:
“What I want to say is that each of us is a certain spacetime pattern in the block universe. Today, or the day of my birth, or the day of my death—all are equally real, all are different pieces of the block universe. I will never stop living this instant. This instant will never cease to exist; this instant has always existed.” (Rucker 1984: 145).
If this were so, then why don’t you have direct access to all past conscious experiences and all future conscious experiences simultaneously in the way you have direct access to the present conscious moment? Or alternatively, why no memories of the future?

Another equally strange interpretation of conscious life and the perception of the present in the Eternalist “block universe” theory is the “eternal return” theory: to put it in simple terms, it is the notion that after death you actually experience your life again, and also exactly as it was before, and yet again after another experience of death, and so on and on, ad infinitum.

To elaborate, there is an infinite “stream” of conscious “yous” following one upon the other, in every instant of the discrete conscious moments of life, and eternally.

As a rough analogy, if each discrete conscious moment of life can be conceived as a frame in a film running in a stream of 1 frames per second, then, if there are 1,000,000 frames to one’s life, it is as if there will always and eternally be 1,000,000 movies playing simultaneously, but each will be running one second out of sync with previous one, with a projection of each and every different frame appearing simultaneously on all screens at any second.

The experience we have now is but one of the movies being projected, and it exists simultaneously with all the other movies running at different points in the sequence of frames: that is, a vast number of conscious “yous” experience a moving present at different points.

That is to say,
(a) You (1) are now reading this sentence;

(b) You (1) have now moved on to reading this sentence, but there is another You (2) who is real and conscious right now reading sentence (a);

(c) You (1) are now reading this, but You (2) is reading (b), and another You (3) is reading (a), and so on ad infinitum.*

*Or are You (1), You (2) and You (3) all just the same person?
Did you read these three sentences? You will now have the conscious experience of reading those same three sentences at this point in your life again and again for eternity, if the “eternal return” theory is true. (Leave my blog immediately if you think you should be doing more important things whose conscious experience will recur cyclically to you in perpetuity!)

If science might confirm – in any sense – the idea of life after death, then this is the only plausible hypothesis ever put forward. If you have a happy and enjoyable life, then you might take solace in such a view. After all, you are eternal!

But if your life is not happy and indeed for anyone whose life is unhappy, unfair and involves suffering, most people will complain that it is a most distressing and disturbing theory of existence.

I have not seen any detailed treatment of the philosophical and ethical implications of the “eternal return” theory (although my reading is limited), because, if it were true, it seems to have extraordinary implications.

But to return to my main point. The problems I identified above do not seem to be resolved by the “eternal return” idea of the perception of one “moving present” amongst an infinitive set of such conscious “presents.” It still does not explain why no one can remember the future or have access to all conscious moments – past, present and future simultaneously. And, above all, how can a dynamic process like an experience of conscious life and moving time be derived from a universe that is timeless and static?

IV. Conclusion
An Eternalist “block universe” theory of time seems incompatible with many conceptions of time and the future assumed by economics, and even (curiously) explanations about the origins of physical and biological phenomena and the direction of causality assumed in science itself.

I return to the question of how the assumptions of economics and social sciences (and common sense), which appear to assume “Presentism,” are to be reconciled with the “Eternalism” of the natural sciences.

There are possible explanations, as follows:
(1) Eternalism is true, and an explanation of its difficulties does exist, but has not been found. This would necessitate radical rethinking of aspects of social sciences, philosophy and even causal explanations in science itself;

(2) the current Eternalist “block universe” theory is wrong. Empirical sciences only ever produce theories that are provisionally true, so perhaps with further future evidence it will emerge that “Presentism” or the “Growing block Universe” theory is true. I will just note that I personally suspect that the “Growing block Universe” theory is the true description of reality.

(3) there is of course another most curious escape hatch. If the static universe is unchanging (by definition) and there is no flow of time, then our mental life cannot be caused by evolving physical events in, or emergent properties of, the brain and its processes. In other words, a materialistic/physicalist explanation of the mind as dependent on changing brain states is impossible. Therefore the human mind – and all its mental life including the perception of a flow of time – is explained by some other process, possibly only explicable in terms of dualism or idealism. Matter and mind are separate. Whatever reality we exist in is all in the mind and not causally related to the material world. So all the findings of modern sciences on time are irrelevant.

I suppose this might appeal to you, if you are a theist or partial to idealism! Alternatively, if our mental life is caused by dynamic physical events in and emergent properties of the brain and its parts, this suggests that a static, timeless universe is not a true description of reality.
At this point, one might be tempted to throw up one’s arms, and admit that one needs a degree in physics and years of research to have anything worthwhile and informed to say about such problems.

If one wants to defend a “Growing block Universe” view, then perhaps a satisfactory resolution can be found in this theory, because it assumes a real flow of time and a future that does not yet exist.

Finally, I post a video below with a talk by the cosmologist George Ellis defending the “Crystallizing Block Universe” theory (his version of the “Growing block Universe” or “Emergent Block Universe” view of time).

I will just note how from 4.30 he describes something that strikes me as remarkably consistent with the Post Keynesian vision of the economic and social world.

George Ellis asserts that at the macro level of the universe with its complex systems (that is, neither quantum nor micro levels of reality) it is remarkable how limited precise scientific prediction is: even the natural sciences cannot precisely predict the past or future from present and past data for many complex macro level phenomena.

From 11.25 onwards, we get a most interesting example of this: the structure and disposition of current galaxies was causally dependent on quantum fluctuations after the Big Bang. But even if one knew everything about those quantum fluctuations, science could not predict the details of the current structure of the universe. See also Ellis and Rothman (2010) for a defense of the “Crystallizing Block Universe” theory.

I add another video below by the Cambridge philosopher Huw Price on the block universe.


Barbour, Julian B. 2000. The End of Time: The Next Revolution in Our Understanding of the Universe. Oxford University Press, New York.

Callender, Craig. 2010. “Is Time an Illusion?,” Scientific American 302.6: 58–65.

Carroll, Sean. “Ten Things Everyone Should Know About Time,” September 1, 2011

Davies, Paul. 2002. “That Mysterious Flow,” Scientific American 287.3: 40–47.

Dunn, Stephen P. 2008. The ‘Uncertain’ Foundations of Post Keynesian economics: Essays in Exploration. Routledge, London and New York.

Ellis, George F. R. and Tony Rothman. 2010. “Time and Spacetime: The Crystallizing Block Universe,” International Journal of Theoretical Physics 49.5: 988-1003.

Lynds, P. 2003. “Subjective Perception of Time and a Progressive Present Moment: The Neurobiological Key to Unlocking Consciousness,”

Maudlin, Tim. 2009. The Metaphysics within Physics. Oxford University Press, Oxford.

Maudlin, Tim. 2012. Philosophy of Physics: Space and Time. Princeton University Press, Princeton, N.J.

Rucker, Rudy von Bitter. 1984. The Fourth Dimension: A Guided Tour of the Higher Universes. Houghton Mifflin, Boston, Ma.

Sukys, Paul. 1999. Lifting the Scientific Veil: Science Appreciation for the Nonscientist. Rowman & Littlefield, Lanham, MD.


  1. I think the way to think about the universe is all possible pasts and all possible futures exist, and that time is an artifact of the spacial temporal limitation and movement of our consciousness through it. Our consciousness has memories of its past and expectations of its future. The path of our consciousness need not be unambiguously determined, and if free will exists, it does so by our choices through it. What is eternal is the full complement of all possibilities, not just one, and what evolves is our consciousness of it in relation to it, with our consciousness and the universe it experiences co evolving together, selecting our path through it. Whatever infinity of possibilities exist, many more are so remote as to be said to fail to exist in that there is no possible path between two points.

    1. Sounds like some version of the many world hypothesis. Yet presumably even that must be a

      (1) a block multiverse, eternal and static (set of all existing sets) or
      (2) an evolving block multiverse where the future is still not yet real.

      In any case, I don't think the fundamental problems sketched above have changed much.

  2. I think that delving into those concepts is quite fruitless. Whether there only exists a present time, or the entire sequence of times exists at once, the answer to this question won't put food on anyone's table. I personally believe that even saying that something abstract exists already puts us amidst the centuries-long dispute between nominalists and realists that couldn't be resolved in any final way, but that might be just me.

    Considering Post-Keynesian uncertainty: doesn't it work regardless whether the the universe is deterministic or not? From our viewpoint, what matters is that it is unpredictable. For example, whether there'll be a war next year might have been or have not been determined at the time of Big Bang, but it doesn't matter for us anyway because we simply don't know the future events.

  3. I'd like to ask if we should try and move on from the reductionism of using physics as the cornerstone for the analysis of time?

    1. Surely, the ultimate explanation of time is the task of physics, it is just they their current Eternalist "block universe" theory looks incorrect.

      In case it is not clear, I think the “Growing block Universe” or “Emergent Block Universe” theory -- apparently a minority view within physics -- looks right and compatible with not just commonsense notions of time, but ideas of time and the future used in Post Keynesianism and heterodox economics.

  4. Your knowledge of philosophy is second to none, LK. I get the impression that you might have taught the subject before in a university setting or had extensive graduate school training. Thanks for the post.

    1. Thanks -- though I have not taught philosophy, have taught some history, however.