Essay Abstract

One of the basic assumptions implicit in the way physics is usually done is that all causation flows in a bottom up fashion, from micro to macro scales. However this is wrong in many cases in biology, and in particular in the way the brain functions. Here I make the case that it is also wrong in the case of digital computers - the paradigm of mechanistic algorithmic causation - and in many cases in physics, ranging from the origin of the arrow of time to the process of quantum state preparation. I consider some examples from classical physics; from quantum physics; and the case of digital computers, and then explain why it this possible without contradicting the causal powers of the underlying micro physics. Understanding the emergence of genuine complexity out of the underlying physics depends on recognising this kind of causation. It is a missing ingredient in present day theory; and taking it into account may help understand such mysteries as the measurement problem in quantum mechanics:

Author Bio

George Ellis is a relativist and cosmologist residing in Cape Town, South Africa. His books include On the Large Scale Structure of Space-Time co-authored with Stephen Hawking. In addition to contemplating relativistic and philosophical aspects of cosmology, he is now engaged in trying to understand how complex systems such as you and me can arise out of the underlying physics.

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  • [deleted]

George,

While I would agree top down effects are under-appreciated in the fundamental sciences, I suggest the real point to be made is the inseparable dichotomy of top down vs. bottom up relations. Often information systems(maths) congeal into top down platonic systems, where the underlaying medium becomes immaterial and dismissed as non-existent. I think it is the feedback between bottom up actions and top down interactions that really forms and informs reality. As Newton said, 'For every action, there is an equal and opposite reaction." Logically actions are linear, but the reactions tend to be non-linear feedback. I don't think it is entirely true that we cannot understand top down activity in terms of bottom up actions, because the initial action creates the potential for feedback and reaction and when this is multiplied across massive scales, feedback becomes infinitely variable. So top down and bottom up are inseparable sides of the same coin. Energy(bottom up) manifests information(top down), as information defines energy.

It is only as processes and states become ever more complex, that we start to loose sight of the fundamental processes still motivating them. The evolution of the brain is a good example: E.O. Wilson described the insect brain as a thermostat, yet it has been shown that varieties of ants use counting footsteps as a navigation tool, so they also have an inherent sequential function as well. I would argue these two functions underlay the conventional divisions of the right hemisphere of the brain as being emotional and intuitive, while the left is analytical and logical. Essentially the right brain is a very evolved thermostat, while the left is an equally evolved sequencer, or clock. So these two very basic functions of measuring energy levels and identifying sequential patterns within this environment, are the salient features of this most evolved and complex manifestation of the universe.

    Dear George,

    An intriguing and very well written essay that raises interesting questions and/or formulates them in new interesting ways.

    Though I believe that any and all interactions can be expressed and described in terms of the fundamental aspects of reality, we lack the theory to do so. And even if we did have such theory that would show all higher scale interactions to be emerging from the fundamental interactions, the amount of data necessary to track every elementary particle and force would prohibit the description of even the simplest systems.

    My understanding is that objects are structurally bound if, within a given scale of reality and under effect of a given force associated with the given scale on them, they behaves as a single object. So, the mathematical models of a particular scale of physical reality can threat composite objects as "virtually fundamental" in such a way that the top-down or bi-directional causalities not only make sense, but becomes the only workable alternative to tracking the interactions between the fundamental particles composing the interacting structures.

    That said, the subject of your essay deserves a lot of consideration. I will certainly explore some of the avenues it opens.

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      Dear Professor Ellis,

      it was a pleasure to read your thought-provoking essay.

      I'd like to comment on just one aspect of your essay: the arrow of time. As I've argued in my essay in this competition, Rethinking a Key Assumption About the Nature of Time, what we perceive as and refer to as "the flow of time" is, in reality, nothing more and nothing less than the evolution of the physical universe, an evolution governed by rules which we strive to understand and which we refer to as the laws of physics. When seen in this light, the so-called "arrow of time" is seen to be inevitable, if not almost trivial.

      To say that the laws of physics are reversible is, in my opinion, a red herring. Yes, of course they are reversible! The fact of the matter, however, is that the universe is comprised of a great deal of macroscopic "stuff" (to use the technical term) which is, for the most part, in motion. We observe that the physical universe is evolving. This evolution represents a great deal of stuff in motion, i.e., a great deal of momentum. Yes, of course it is true that particle A or object A theoretically *could* be moving from right to left from your perspective, but if it is, in fact, moving from left to right from your perspective, then that is hard, objective reality! Particle A or object A can't be moving in both directions! Taken on the scale of the entire universe, it is this evolution of "stuff" that we perceive as "the flow of time," or, alternatively, as what we call "the arrow of time." This of course does not rule out reversibility at the microscopic, thermodynamic level of a gas, for example.

      If I've correctly understood the point of your essay, these observations support your thesis.

      Best regards,

      jcns

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        Hello George, great job on the essay, and thank you for participating. I was surprised that you didn't specifically mention rescuing free will, as this seems to be what you are getting at in the section on state vector preparation. An experimenter's brain/body, in choosing a polarization angle for example, is imposing top-down causation upon the apparatus and ultimately upon the micro systems prepared, correct?

        I couldn't help noticing similarities between your diagrams 1/6/7 and Figure 1 in my essay, which is based on a graphical formalism developed by Bob Coecke at Oxford. I tried to come up with a sketch for a top-down causation mechanism by tracing the flow of contextual information, where complex systems impose context-specific boundary conditions upon measurement events, thereby generating further-enriched complexity in the process. This results in a universe of ever-increasing complexity. I hope you have the time to give it a look.

          • [deleted]

          George

          "A sensible view is that the entities at each classical level of the hierarchy (Table 1) are real"

          While this reflects the normal, and indeed practical, view of physical reality, it is ontologically (physically) incorrect. Because certain existent, but superficial, physical characteristics are deemed to constitute any given 'it' (eg computer, you, etc). That 'it' is then thought to remain in existence, albeit with changes occurring to it, until one or more of the defining characteristics is no longer manifest. However, this just depicts reality at a higher level than the actuality, though it could be correct, in itself, at that level. Physically, that 'it' is a sequence of physically existent states. The higher level of differentiation just giving the appearance of less change than there physically is, and the illusion of a level of persistence to existence which does not physically occur.

          For physical reality to occur, and alter, there must ultimately be a physically existent state at any given point in time. This can be defined as the state of the properties of the elementary particles involved, and their spatial position, as at that point in time. So there is a "fixed set of lower level entities". And, by definition, any "event" could be tracked back to alterations at that level. That is, physically it must be 'bottom up'.

          The point here is that while that is physically what occurs, we could never establish it in such detail, and would probably all go mad trying. So, we conceptualise up some levels. But we must maintain ontological/physical correctness about the direction of the process. What is ultimately causing alteration in the properties of elementary particles and hence a change in their spatial position is another issue.

          Another point to bear in mind that what exists is a present (ie that which was physically existent as at a given point in time). Previous existences have ceased (the past) as at that point in time. Successive existences (the future) do not exist. In other words, one does not affect the future, what happens is that a present occurs which is different to the one which would have otherwise done so.

          Paul

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            John

            There is a presumption in here that, to put it simply, the future can be affected. Which it cannot. Because it does not exist, and is therefore not available to be affected. Or put another way, "reactions" are just the next set of "actions". The brain, etc is irrelevant to physical existence.

            Paul

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            JCN

            "This of course does not rule out reversibility at the microscopic, thermodynamic level of a gas, for example"

            Of course it does. Physical alteration occurs, it cannot then be reversed. The sequence can involve a subsequent state which is identical to a previous one, but that is not reversal.

            Paul

            • [deleted]

            Paul,

            Since present is cause to future effect, it is affected. If I was to break a leg today, it would certainly affect what I will be doing tomorrow.

            "Reactions" may be just the next set of "actions," but notice you included the plural. The action, as we tend to perceive it, is singular, while the environmental reactions to it are plural. The feedback from a complex environment to a simple action is complex.

            The brain evolved out of physical existence and is a reflection of it, thus both time and temperature are foundational to its functions.

            George, this is just a wonderful piece of work, far worthier of more honor than any prize competition could bestow. I suppose that should come as no surprise -- if anyone were capable of distilling the history and dynamics of the entire universe into 10 pages, it would be you.

            " ... life would not be possible without a well-established local arrow of time." So well put. And "Emergence of genuine complexity is characterised by a reversal of information flow from bottom up to top down." If you get a chance to vist my essay site, I would hope to convince you that both conditions are satisfied by topological orientability in a coordinate-free locally realistic model.

            Again, thanks for this great paper.

            Tom

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              Paul,

              With apologies to Professor Ellis for what probably is a distraction from the main point of his essay, insofar as it may bear at least tangentially on his topic I will reply to your post here, but if we wish to pursue this debate further we should move the discussion to one of our own blogs. You wrote:

              "The sequence can involve a subsequent state which is identical to a previous one, but that is not reversal."

              This is the thing you've never appeared to comprehend, Paul. According to my view of time (which I believe is consistent with Julian Barbour's view, in this regard at least), a particular time is identically equivalent to a particular configuration of the universe. This is my preferred wording of the concept which Barbour expresses by stating that "The relative configurations, or shapes, of the Universe do not occur at instants of time . . . they are the instants of time."

              By this way of thinking, if the configuration of the universe were, hypothetically, to oscillate between two identically equivalent configurations, then time would oscillate between those two particular times. That said, however, things would get sticky because of the momentum involved in such an oscillation. The precise moments representing the end points of the oscillatory motion would be identically equivalent configurations and identically equivalent particular times. This sort of thing is easier to envision if we think of the universe as comprised entirely of three not-further-reducible billiard balls in a not-further-reducible shoebox.

              I have no desire whatsoever to belabor this argument further, Paul, here or elsewhere, but if you insist on doing so, please pick another blog (yours or mine) where we may do so. Thanks.

              jcns

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              John

              "If I was to break a leg today, it would certainly affect what I will be doing tomorrow".

              Yes, the present that subsequently occurs is different from what it would have been. But what it would have been never existed. The future does not exist, so you cannot affect it.

              As above, reactions are the next actions, the fact that I used the plural form of these words is irrelevant. My point was a repetition of the above. While they can be depicted as reactions, there is no form of reversal of physical existence. Everything could be described as a reaction to something.

              Brains are physically existent, not a "reflection" of it, so are eyes, ears, etc. We are not somehow external to physical existence. What is different in sentient organisms that they possess a processing capability that enables them to be aware of the physical existence.

              Paul

              • [deleted]

              JCN

              As requested I will copy this and a response across to my blog, but hopefully people will follow that, because there is not much point in us two having a repeat of previous exchanges amongst ourselves.

              Paul

              • [deleted]

              Dear Professor Ellis,

              Your meticulously crystal clear cogent reasoned essay seems to me to be one of the more superior reads of the essays published at this website so far. That said, I think the Universe is the simplest structuring emerging. There is and ever will be only one Universe once although it seem to be having three differing aspects only one of which is seeing appearing. As I have thoughtfully pointed out in my essay, Sequence Consequence, identical snowflakes have never existed so it is reasonable to assume that identical physical states cannot ever exist. I contend that when you pressed down the letter A on your computer keyboard, the A you produced on your computer screen was not only minutely different from all of the other A's on your computer screen, it would also have to be different than any other A that has ever appeared on any computer screen in the past, different than any A presently appearing on any computer screen located anywhere on earth, and also different than any A that will ever appear on any computer screen that will ever become operational in the future. There is only one of anything once in the one real Universe once. Each one of anything will seem to be having three aspects only one of which one can see here and now.

                John, thanks for that. You state "I think it is the feedback between bottom up actions and top down interactions that really forms and informs reality." We agree. It is the inter level feedback loops that generate real complexity.

                As to the nature of time issue: I basically agree with you. See

                http://arxiv.org/abs/gr-qc/0605049

                Dear Daniel, thanks for that.

                As to your second para, the issue is what are "fundamental aspects of reality". One does not have to agree that the only such aspects are those described by physics: what abut mathematics for example? Or logic?

                Your third para is more or less agreeing with me. See my answers to others below

                Hi Paul

                Thanks for the comments

                > "A sensible view is that the entities at each classical level of the hierarchy (Table 1) are real". While this reflects the normal, and indeed practical, view of physical reality, it is ontologically (physically) incorrect.

                • well you are stating the standard fundamentalist reductionist viewpoint. It may or may not be true.

                > Because certain existent, but superficial, physical characteristics are deemed to constitute any given 'it' (eg computer, you, etc). That 'it' is then thought to remain in existence, albeit with changes occurring to it, until one or more of the defining characteristics is no longer manifest. However, this just depicts reality at a higher level than the actuality, though it could be correct, in itself, at that level.

                • Your definition of actuality. Not mine or for example Feynman's or Anderson's or Schweber's. Yes it is correct at that level. And as that level has causal powers, it is real (see my definition 2). Please look at your computer in order to confirm for yourself that higher levels have causal powers (unless you believe the computer came into existence without cause). Or maybe you claim the computer does not really exist? I can't deal with that kind of obscurantism.

                > Physically, that 'it' is a sequence of physically existent states. The higher level of differentiation just giving the appearance of less change than there physically is, and the illusion of a level of persistence to existence which does not physically occur.

                • Your definition of existence. Not mine or your bank manager's. This kind of statement reminds me strongly of some Eastern religions. The level of persistence is real, it is the basis of daily life. Assuming of course that daily life exists. If it does not, then physicists and physics experiments don't exist.

                > For physical reality to occur, and alter, there must ultimately be a physically existent state at any given point in time. This can be defined as the state of the properties of the elementary particles involved, and their spatial position, as at that point in time.

                • This statement has not taken present day quantum theory on board. It is precisely at the particle level that reality is unclear, because of (i) the uncertainty principle, (ii) wave-particle duality, and (iii) entanglement. Many quantum field theorists claim there are no particles, only fields. And string theorists claim they are vibrations in superstrings. Is that "real"? On your reductionist view, it follows that the particles don't exist either: they are "nothing but" excitations of strings (if we believe those exist). A present day view should at least take quantum physics into account, if not string theory (which is not a solid foundation, as it is not even well defined, let alone proven to be right).

                > So there is a "fixed set of lower level entities". And, by definition, any "event" could be tracked back to alterations at that level. That is, physically it must be 'bottom up'.

                • Well you seem not to have read the party of my essay where I carefully explain that there are often not fixed lower level entities: their nature, or indeed their existence, is dependent on their higher level context. In the case of string theory, the nature of particles depends on the string theory vacuum - a non-local higher context for their existence. Their properties are not invariant, they depend on this vacuum. You are using a billiard ball metaphor that does not apply to "fundamental reality", i.e. the lowest levels of existence we can understand.

                > The point here is that while that is physically what occurs, we could never establish it in such detail, and would probably all go mad trying. So, we conceptualise up some levels. But we must maintain ontological/physical correctness about the direction of the process. What is ultimately causing alteration in the properties of elementary particles and hence a change in their spatial position is another issue.

                • what process? conceptualisation? Actually we conceptualise down, on the basis of our physics experiments, from the level of daily life to the micro level. That's the real direction of the process of physics theorising. As to "causing alterations" - the heart of causation - ultimately, it is top-down effects that decide what changes in lower level entities will take place, because they set the scene for the lower level actions. That context determines the specific outcomes that occur.

                > Another point to bear in mind that what exists is a present (ie that which was physically existent as at a given point in time). Previous existences have ceased (the past) as at that point in time. Successive existences (the future) do not exist.

                • Agreed

                > In other words, one does not affect the future, what happens is that a present occurs which is different to the one which would have otherwise done so.

                • Strange phraseology but more or less in accord with my proposal of an Evolving Block Universe (EBU): see http://arxiv.org/abs/gr-qc/0605049

                I did not have space to give all the references I would have liked to include. One that is great is Eddington's book The Nature of the Physical World, which is far deeper than many more recent writings (see his earlier chapters for the relation between physical reality and the mathematical models that some people mistake for reality). I'll put up Feynman's writing on this theme of levels of reality in a separate post.

                However you have not responded to my main challenge. How does the existence of computer programs relate to your concept of actuality? Do you claim

                • They don't exist? - then their outcomes, such as aircraft designed via computers, are uncaused and just appear magically

                • They exist and are made up of elementary particles? - if so what are these particles an din what way do the constitute a computer program>?

                • They exist and are not made up of particles? - this of course is my position. Can't see that either of the others makes sense.

                George

                Thanks for those comments. Yes they seem to support my thesis.

                My views in the flow of time are at see http://arxiv.org/abs/gr-qc/0605049.

                I'll be doing more on this later this year.

                Thanks for that. Yes if I had more space I was going to add that the discovery of the Higgs is an example of top down causation from the human mind to the level of particles, causing them to smash together in a preplanned way in the LHC.

                Your emphasis on the contextual nature of information is in accord with my view.

                • [deleted]

                Dear Professor Ellis,

                We are in between the bottom up and top down approaches of information flow. Relativistic universe is in a constant flux of this information flow and it is in an infinite feed back loop. Conscience is both at the absolute center and outer periphery of the universe (holographic effect). We as individual beings are caught in between these two equivalent states (singularity) and percieve the relativistic universe as a virtual reality.

                Please see the essay

                Conscience is the cosmological constant.

                Love,

                Sridattadev.