In this paper, we discuss the implications for the determinateness and intersubjective consistency of conscious experience in two gedanken experiments from quantum mechanics (QM). In particular, we discuss Wigner's friend and the delayed choice quantum eraser experiment with a twist. These are both cases (experiments) where quantum phenomena, or at least allegedly possible quantum phenomena/experiments, and the content/efficacy of conscious experience seem to bear on one another. We discuss why these two cases raise concerns for the determinateness and intersubjective consistency of conscious experience. We outline a 4D-global constraint-based approach to explanation in general and for QM in particular that resolves any such concerns without having to invoke metaphysical quietism (as with pragmatic accounts of QM), objective collapse mechanisms or subjective collapse. In short, we provide an account of QM free from any concerns associated with either the standard formalism or relative-state formalism, an account that yields a single 4D block universe with determinate and intersubjectively consistent conscious experience for all conscious agents. Essentially, the mystery in both experiments is caused by a dynamical/causal view of QM, e.g., time-evolved states in Hilbert space, and as we show this mystery can be avoided by a spatiotemporal, constraint-based view of QM, e.g., path integral calculation of probability amplitudes using future boundary conditions. What will become clear is that rather than furiously seeking some way to make dubious deep connections between quantum physics and conscious experience, the kinds of 4D adynamical global constraints that are fundamental to both classical and quantum physics and the relationship between them, also constrain conscious experience. That is, physics properly understood, already is psychology.
Bradford Skow reviewed our book for the Notre Dame Philosophical Reviews and therein provided an example of what happens when the reader is unwilling or unable to suspend their dynamical bias while reading the book. We warn the reader in Chapter 1:
This [dynamical bias] is a very hard bias to overcome; ironically even the many philosophers and physicists who claim to believe in the block universe ontology still adopt the ant’s-eye view and assume that fundamental explanation is [dynamical]. Therefore, we must ask that you make every effort to suspend this dynamical bias as you read the book.
But, he writes:
It really is necessary to register how wild this idea is. I myself, at least, think that the first claim [dynamical explanation] is true but that the second [adynamical explanation] is certainly false.
This leads him to dismiss out-of-hand our 4D-constraint-based explanation:
Of course, if you explain the initial state of the universe by citing a later state, you probably shouldn’t explain that later state by citing the initial state; it can't be both that A because B and B because A. If physicists follow SSM's advice, can they then explain every state of the universe? That is, for each region of spacetime, can they explain why that region of spacetime is in the state it is in, without ever asserting both "A because B" and "B because A"? If this cannot be done then there is at least one region of spacetime with the property that that region's being in such-and-such a state remains unexplained.
If you understand and are willing to consider the thesis presented in the book, then you can see immediately by the reviewer’s statement that his questions miss the point entirely. Einstein’s equations can be viewed as a self-consistency constraint as explained in Chapter 3. First, we explain what the metric is and how the left-hand side of Einstein’s equations (the Einstein tensor) is a very complex function of the spacetime metric. Then on p. 105:
The SET [right-hand side of Einstein’s equations] describes the matter–energy-momentum distribution in spacetime, so in order to provide the elements of the SET you have to know spatial and temporal distances for momentum, force, and energy. Of course, knowing spatial and temporal distances means you already know the metric. Therefore, you should view Einstein’s equations as providing a self-consistency criterion or a “global constraint” between what you mean by spatial and temporal measurements and what you mean by momentum, force, and energy. Any combination of the metric and SET that solves Einstein’s equations on the spacetime manifold M constitutes a solution of GR.
With this understanding it is obvious that indeed the GR solution at any point on M depends self-consistently on the solution at all other points on M, just like a crossword puzzle. So, yes, “A because B” and “B because A” per the adynamical global constraint (AGC, Einstein’s equations in this case) is exactly what adynamical explanation means. We answer his questions on p. 110:
Ultimately, a solution—a self-consistent metric and SET on the entirety of M—depends on two things: the adynamical global constraint (Einstein’s equations) and information in accord with observations for any location on M. In this block universe perspective, one could still ask regarding spacetime, “why do we observe what we observe rather than something else?” This question replaces its counterpart in the mechanical universe, “why these initial conditions rather than some other?” In [adynamical explanation], conditions at any location on M are said to be consistent with conditions elsewhere on M. It is this spatiotemporal contextual consistency per the adynamical global constraint that ultimately explains the conditions at any particular point on M in relation to all other points on M. There is no explanatory priority of one location over another in [adynamical explanation]. Accordingly, the only mystery would be the existence of M as a whole which is beyond empirical investigation and therefore beyond the purview of physics in this way of thinking. Thus, most would say that the principle of sufficient reason (PSR) cannot be satisfied on cosmological scales by empirical science in our “spatiotemporal ontological contextuality.”
And again on pp. 114-115:
Again, one could ask, “why is there an M at all?” And, certainly one could engage in speculation concerning M with metric-SET configurations and/or adynamical global constraints that do not represent our experience. Such counterfactual speculation wouldn’t lend itself to empiricism, by definition, but we wouldn’t condemn it as an “unworthy academic exercise” either. The point is that while we speak of doing physics from a God’s-eye view, given our contextuality and relationalism, there is no literal “view from nowhere” [Nagel, 1986] from which to ask “why does the entire relational block universe exist?” Such questions presuppose the dynamical perspective and the only answer one can give to such questions in our view will be in terms of counterfactual adynamical global constraints and alternative metric-SET configurations, that is, answers residing outside the purview of empirical science.
Again, these mysteries arise because the time-evolved bias of our ant’s-eye view demands dynamical explanation and a dynamical story about the universe traced backward in time leads ultimately to conditions in the very early universe. Again, per Wilczek, “The account it gives—things are what they are because they were what they were—raises the question, Why were things that way and not any other?” [Wilczek, 2016, p. 37]. The key to avoiding this explanatory problem is to relegate dynamical explanation based on time-evolved stories to secondary (non-fundamental) status and accept that the more general block universe explanation based on a spatiotemporally global constraint is truly fundamental. This is adynamical explanation per the Lagrangian Schema Universe. In this more general adynamical explanation, Einstein’s equations are understood as a global constraint, that is, a self-consistency criterion for the metric and SET on the spacetime manifold M. While time-evolved stories can certainly be told in GR solutions, there well may be events in a GR solution that resist such dynamical explanation, for example, the origin of the universe or the question “why were things that way and not any other?” In those cases, we just have to accept that reality is best understood adynamically in spatiotemporally holistic fashion.
So, you cannot be "Skowed" if you want to appreciate the explanatory power of the "all-at-once" view and rise to Wilczek's challenge. You must set aside your dynamical bias as you read the book!
In this Physics Forums Insight, I show how the Popescu-Rohrlich (PR) correlations provide an unreasonable advantage in a particular “quantum guessing game” using a pedagogical counterpart from the book “Totally Random: Why Nobody Understands Quantum Mechanics” by Tanya Bub and Jeffrey Bub (Princeton University Press, 2018).
I show that the PR correlations are not just a little bit better than quantum correlations for the quantum guessing game, they are unreasonably effective. In fact, they violate the conservation of binary information, which translates into conservation of angular momentum on average when the information regards spin as I showed in Why the Quantum. So, it is probably the case that a physical instantiation of the PR correlations is a pipe dream akin to a perpetual motion machine.
In this Physics Forums Insight I introduce the quantum mystery called “Wigner’s friend.” As in my previous Insights, I show how this mystery results from dynamical/causal explanation per the “ant’s-eye view” and is resolved by spatiotemporal-constraint-based explanation in the block universe view (Wilzcek’s “God’s-eye view”).
In 1981, Mermin published a now famous paper titled, "Bringing home the atomic world: Quantum mysteries for anybody." Therein, he presented the 'Mermin device' that illustrates the conundrum of entanglement per the spin singlet state for the "general reader." He then challenged the "physicist reader" to explain the way the device works "in terms meaningful to a general reader struggling with the dilemma raised by the device." In this paper, I show how the conservation of angular momentum on average answers that challenge, but still leaves a mystery for those who seek hidden variables or 'causal influences' behind this otherwise straightforward conservation principle.
To answer Wheeler's question "Why the quantum?" via quantum information theory according to Bub, one must explain both why the world is quantum rather than classical and why the world is quantum rather than superquantum, i.e., "Why the Tsirelson bound?" We show that the quantum correlations resulting from spin one-half states, i.e., the spin singlet state and 'Mermin photon state', which uniquely produce the Tsirelson bound for the Clauser-Horne-Shimony-Holt (CHSH) quantity, can be derived from the conservation of angular momentum (on average) for the quantum exchange of momentum. This explanation of the Tsirelson bound does not require hidden variables or 'causal influences', local or nonlocal. Since superquantum correlations exceed quantum correlations, we know that they would also violate conservation of angular momentum and we show how this happens using the Popescu-Rohrlich (PR) correlations. Thus, quantum correlations responsible for the Tsirelson bound satisfy conservation of angular momentum for the quantum exchange of momentum while both classical and superquantum correlations can fail to satisfy this constraint. We generalize the result to conservation per any measurement associated with a Bell basis state. While this constraint is not surprising per se, the details on how it obtains evidence a deeper principle at work in Nature, i.e., no preferred reference frame.
This is a link to our OUP Blog post, "Ascending to the god's-eye view of reality."
A recurring theme in natural philosophy is the tension between the God's-eye view of reality comprehended as a whole and the ant's-eye view of human consciousness, which senses a succession of events in time. Since the days of Isaac Newton, the ant's-eye view has dominated fundamental physics. We divide our description of the world into dynamical laws that, paradoxically, exist outside of time according to some, and initial conditions on which those laws act. The dynamical laws do not determine which initial conditions describe reality. That division has been enormously useful and successful pragmatically, but it leaves us far short of a full scientific account of the world as we know it. The account it gives – things are what they are because they were what they were – raises the question, Why were things that way and not any other? The God’s-eye view seems, in the light of relativity theory, to be far more natural. Relativity teaches us to consider spacetime as an organic whole whose different aspects are related by symmetries that are awkward to express if we insist on carving experience into time slices. Hermann Weyl expressed the organic view memorably in his 1949 book Philosophy of Mathematics and Natural Science (Princeton University Press, page 116):
"The objective world simply is, it does not happen. Only to the gaze of my consciousness, crawling upward along the life line of my body, does a section of this world come to life as a fleeting image in space which continuously changes in time."
To me, ascending from the ant’s-eye view to the God’s-eye view of physical reality is the most profound challenge for fundamental physics in the next 100 years.
Frank Wilczek: Physics in 100 Years. Physics Today 69(4), 32-39 (2016).
Theoretical physics and foundations of physics have not made much progress in the last few decades. Whether we are talking about unifying general relativity and quantum field theory (quantum gravity), explaining so-called dark energy and dark matter (cosmology), or the interpretation and implications of quantum mechanics and relativity, there is no consensus in sight. In addition, both enterprises are deeply puzzled about various facets of time including above all, time as experienced. The authors argue that, across the board, this impasse is the result of the “dynamical universe paradigm,” the idea that reality is fundamentally made up of physical entities that evolve in time from some initial state according to dynamical laws. Thus, in the dynamical universe, the initial conditions plus the dynamical laws explain everything else going exclusively forward in time. In cosmology, for example, the initial conditions reside in the Big Bang and the dynamical law is supplied by general relativity. Accordingly, the present state of the universe is explained exclusively by its past. This book offers a completely new paradigm (called Relational Blockworld), whereby the past, present and future co-determine each other via “adynamical global constraints,” such as the least action principle. Accordingly, the future is just as important for explaining the present as is the past. Most of the book is devoted to showing how Relational Blockworld resolves many of the current conundrums of both theoretical physics and foundations of physics, including the mystery of time as experienced and how that experience relates to the block universe.