I've been trying to write-up a concise, clear, and coherent argument against the idea that determinism, or more precisely any deterministic worldview that implicitly or explicitly relies in some way on determinism in physics, is flawed. I have thus far failed to write anything that met all three criteria. I have therefore included a draft of a (fairly) concise (at least for me) version that I hope others might find interesting enough (or confusing enough) to make suggestions concerning, pose questions about, point out flaws made, or post reactions/criticisms more generally. Thanks!
Consider the classical and infamous formulation of determinism given by Laplace:
“We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.”
[Nous devons donc envisager l'état présent de l'univers comme l'effet de son état antérieur, et comme la cause de celui qui va suivre. Une intelligence qui pour un instant donné connaîtrait toutes les forces dont la nature est animée et la situation respective des êtres qui la composent, si d'ailleurs elle était assez vaste pour soumettre ces données à l'analyse, embrasserait dans la même formule les mouvements des plus grands corps de l'univers et ceux du plus léger atome: rien ne serait incertain pour elle, et l'avenir, comme le passé, serait présent à ses yeux.]
This”intelligence” or “intellect” which is capable of representing and analyzing the configuration state of the universe at a particular moment is, according to the deterministic worldview, at least in principle capable of predicting all future states arbitrarily far into the future. Everything is determined.
It is important to understand that Laplace intended this “intellect” to be a kind of idealized physicist/natural philosopher, not a deity or some being with magical abilities. One could consider this “intellect” as a kind of epistemic determinism in which, at least in principle, given complete knowledge of the state of any and all systems (including the entire cosmos) at some point in time, all future states can in principle (if not in practice) be known. A better way of understanding “Laplace’s demon” (why it is often described as a demon, including in the Wikipedia article, I don’t know) is as a physicist with a computer capable of storing the data of all forces acting on all “items of which nature is composed” and the positions of these items, and of plugging them into the requisite equations from physics (e.g., Newton’s equations of motion).
Either interpretation emphasizes the fallacy inherent in this conception of deterministic laws of physics. In classical physics and largely in modern physics, we extrapolate general laws by isolating various systems and studying how they “evolve” in time. We then generalize regularities found, encoding them in equations such as the (second-order) partial differential equation Force= mass * acceleration or Maxwell’s equations. The problem is that in all laws and theories derived from this method, from Newton’s laws to Einstein’s equations, we have removed ourselves. To illustrate this better, let’s consider Laplace’s intellect again.
As an idealized physicist, this “intellect” exists in the universe, as does whatever means (enormous brain, computer, etc.) it uses to store the configuration state of the universe and analyze it using the mathematics of the laws of physics. To simplify things, let’s assume that the “intellect” consists of a physicist plus a computer which can be fed the data of the state of the ‘universe system” at some time and calculate all future states using the equations of the laws of physics. The physicist and the computer exist in the universe. Thus the computer must, in addition to storing the requisite information on the rest of the universe, encode the precise configurations of particles which compose itself and the physicist. But this means that the computer must store this information somewhere, and that place ALSO exists in the universe. This in turn means that the physical particles that make-up this storage must be encoded by the computer for analysis. Ad infinitem.
Put differently, in order for any intellect that isn’t supernatural to be able to encode the specifications on the configuration of all particles in the universe, this intellect must encode include its own state. But to represent its own state physically (to encode or “store” it as data) it needs to expand the universe (it needs more particles than itself and the rest of the universe to represent the state of itself and the rest of the universe).
Put MOST simply, I can’t encode the state of the universe and analyze these data to calculate the future without being outside of the universe.
THAT’s the fallacy of the deterministic description of the cosmos from the perspective of physics. No matter how many times we analyze isolated systems to extract general laws that describe the evolution of general systems, we do so by writing ourselves out of the picture.
Quantum indeterminism is arguably nothing more radical than our own intuition. We cannot sufficiently isolate quantum systems in a way that allows us to pretend we aren’t conscious agents setting up experiments, making calculations, and building models. We can’t be “passive” observers whose observations don’t disturb the systems, but necessarily are participatory observers (to use Wheeler’s phrase). The indeterminacy of quantum theory is perhaps most important because it highlights the fact that in order to pretend classical physics shows the classical world is deterministic we had to
1) Pretend we, as the observers studying these systems, didn’t exist (that we could sufficiently isolate systems to ignore the influence of observation/measurement)
2) Having written ourselves out of the description, we were logically justified in then including ourselves in the domain of the applications of our descriptions (equations/laws).
This last point has been made elsewhere, and I include an example of another’s formulation:
“A key observation which is central to our argument is that it is fallacious to take methods and formal frameworks which have proved successful when applied to small subsystems of the universe and apply them to the universe as a whole...the [reason] Newtonian paradigm cannot be extended to the whole universe is that its success relies on our ability to cleanly separate the roles of the initial conditions from the laws in explanations of physical phenomena. But this separation in turn relies on our ability to do an experiment many times while varying the initial conditions. Only by making use of the freedom to run an experiment over and over again with different initial conditions can we determine what the laws are – for the laws code regularities that are invariant under variation of the initial conditions.”
Smolin, L., and Unger, R. M. (2015). The Singular Universe and the Reality of Time. Cambridge University Press.
It is often argued or claimed that quantum mechanics and quantum theory more generally offer some kind of alternative to the determinism of classical physics, and moreover the ONLY alternative. This is not really correct. In reality, quantum physics showed us that we made a serious logical fallacy in extending the laws we developed by extrapolating from the dynamics of mechanical systems in some idealized isolation to the whole of reality. Quantum physics forced us to include ourselves as observers and stop pretending that our descriptions of mechanical systems were limited to these.
As a final demonstration of the flaws of thinking classical deterministic physics could, even in principle, apply to us, consider the infamous law of the conservation of energy (or of momentum, or of energy-momentum). It is often not stated that this law (or these laws) only holds for isolated (or more accurately “closed”) systems. In experimental practice, the violation of the conservation of energy is practically a given, because
1) We are never able to actually create closed systems or model systems as closed without being inaccurate
&
2) Whenever we do not find energy to be conserved, we either modify theory (e.g., by changing the conservation law to the conservation of energy-momentum, among other things), or far more commonly we conclude that the system wasn’t “closed”. In other words, the criterion that the conservation of energy holds only for closed systems is used to determine whether a system is closed.
It is the second of these that is the more important. It is circular (at least partially). The energy is conserved in any system which is closed, but we don’t have any way of determining whether a system is closed without conservation laws. More fundamentally, every experiment that is closed doesn’t include the scientists running the experiment, and thus even in principle there can be no experiment which shows that the most fundamental conservation laws hold in general because such an experiment would include systems outside of the experiment (namely, the experimenters and whatever technology they used).
The only scientific foundations for determinism (classical physics, which is deterministic) only works because in classical physics we use free will to determine how to measure/observe systems which we have excluded ourselves from, and then include ourselves and everything else as being governed by the descriptions we obtain from these observations/measurements.
Consider the classical and infamous formulation of determinism given by Laplace:
“We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.”
[Nous devons donc envisager l'état présent de l'univers comme l'effet de son état antérieur, et comme la cause de celui qui va suivre. Une intelligence qui pour un instant donné connaîtrait toutes les forces dont la nature est animée et la situation respective des êtres qui la composent, si d'ailleurs elle était assez vaste pour soumettre ces données à l'analyse, embrasserait dans la même formule les mouvements des plus grands corps de l'univers et ceux du plus léger atome: rien ne serait incertain pour elle, et l'avenir, comme le passé, serait présent à ses yeux.]
This”intelligence” or “intellect” which is capable of representing and analyzing the configuration state of the universe at a particular moment is, according to the deterministic worldview, at least in principle capable of predicting all future states arbitrarily far into the future. Everything is determined.
It is important to understand that Laplace intended this “intellect” to be a kind of idealized physicist/natural philosopher, not a deity or some being with magical abilities. One could consider this “intellect” as a kind of epistemic determinism in which, at least in principle, given complete knowledge of the state of any and all systems (including the entire cosmos) at some point in time, all future states can in principle (if not in practice) be known. A better way of understanding “Laplace’s demon” (why it is often described as a demon, including in the Wikipedia article, I don’t know) is as a physicist with a computer capable of storing the data of all forces acting on all “items of which nature is composed” and the positions of these items, and of plugging them into the requisite equations from physics (e.g., Newton’s equations of motion).
Either interpretation emphasizes the fallacy inherent in this conception of deterministic laws of physics. In classical physics and largely in modern physics, we extrapolate general laws by isolating various systems and studying how they “evolve” in time. We then generalize regularities found, encoding them in equations such as the (second-order) partial differential equation Force= mass * acceleration or Maxwell’s equations. The problem is that in all laws and theories derived from this method, from Newton’s laws to Einstein’s equations, we have removed ourselves. To illustrate this better, let’s consider Laplace’s intellect again.
As an idealized physicist, this “intellect” exists in the universe, as does whatever means (enormous brain, computer, etc.) it uses to store the configuration state of the universe and analyze it using the mathematics of the laws of physics. To simplify things, let’s assume that the “intellect” consists of a physicist plus a computer which can be fed the data of the state of the ‘universe system” at some time and calculate all future states using the equations of the laws of physics. The physicist and the computer exist in the universe. Thus the computer must, in addition to storing the requisite information on the rest of the universe, encode the precise configurations of particles which compose itself and the physicist. But this means that the computer must store this information somewhere, and that place ALSO exists in the universe. This in turn means that the physical particles that make-up this storage must be encoded by the computer for analysis. Ad infinitem.
Put differently, in order for any intellect that isn’t supernatural to be able to encode the specifications on the configuration of all particles in the universe, this intellect must encode include its own state. But to represent its own state physically (to encode or “store” it as data) it needs to expand the universe (it needs more particles than itself and the rest of the universe to represent the state of itself and the rest of the universe).
Put MOST simply, I can’t encode the state of the universe and analyze these data to calculate the future without being outside of the universe.
THAT’s the fallacy of the deterministic description of the cosmos from the perspective of physics. No matter how many times we analyze isolated systems to extract general laws that describe the evolution of general systems, we do so by writing ourselves out of the picture.
Quantum indeterminism is arguably nothing more radical than our own intuition. We cannot sufficiently isolate quantum systems in a way that allows us to pretend we aren’t conscious agents setting up experiments, making calculations, and building models. We can’t be “passive” observers whose observations don’t disturb the systems, but necessarily are participatory observers (to use Wheeler’s phrase). The indeterminacy of quantum theory is perhaps most important because it highlights the fact that in order to pretend classical physics shows the classical world is deterministic we had to
1) Pretend we, as the observers studying these systems, didn’t exist (that we could sufficiently isolate systems to ignore the influence of observation/measurement)
2) Having written ourselves out of the description, we were logically justified in then including ourselves in the domain of the applications of our descriptions (equations/laws).
This last point has been made elsewhere, and I include an example of another’s formulation:
“A key observation which is central to our argument is that it is fallacious to take methods and formal frameworks which have proved successful when applied to small subsystems of the universe and apply them to the universe as a whole...the [reason] Newtonian paradigm cannot be extended to the whole universe is that its success relies on our ability to cleanly separate the roles of the initial conditions from the laws in explanations of physical phenomena. But this separation in turn relies on our ability to do an experiment many times while varying the initial conditions. Only by making use of the freedom to run an experiment over and over again with different initial conditions can we determine what the laws are – for the laws code regularities that are invariant under variation of the initial conditions.”
Smolin, L., and Unger, R. M. (2015). The Singular Universe and the Reality of Time. Cambridge University Press.
It is often argued or claimed that quantum mechanics and quantum theory more generally offer some kind of alternative to the determinism of classical physics, and moreover the ONLY alternative. This is not really correct. In reality, quantum physics showed us that we made a serious logical fallacy in extending the laws we developed by extrapolating from the dynamics of mechanical systems in some idealized isolation to the whole of reality. Quantum physics forced us to include ourselves as observers and stop pretending that our descriptions of mechanical systems were limited to these.
As a final demonstration of the flaws of thinking classical deterministic physics could, even in principle, apply to us, consider the infamous law of the conservation of energy (or of momentum, or of energy-momentum). It is often not stated that this law (or these laws) only holds for isolated (or more accurately “closed”) systems. In experimental practice, the violation of the conservation of energy is practically a given, because
1) We are never able to actually create closed systems or model systems as closed without being inaccurate
&
2) Whenever we do not find energy to be conserved, we either modify theory (e.g., by changing the conservation law to the conservation of energy-momentum, among other things), or far more commonly we conclude that the system wasn’t “closed”. In other words, the criterion that the conservation of energy holds only for closed systems is used to determine whether a system is closed.
It is the second of these that is the more important. It is circular (at least partially). The energy is conserved in any system which is closed, but we don’t have any way of determining whether a system is closed without conservation laws. More fundamentally, every experiment that is closed doesn’t include the scientists running the experiment, and thus even in principle there can be no experiment which shows that the most fundamental conservation laws hold in general because such an experiment would include systems outside of the experiment (namely, the experimenters and whatever technology they used).
The only scientific foundations for determinism (classical physics, which is deterministic) only works because in classical physics we use free will to determine how to measure/observe systems which we have excluded ourselves from, and then include ourselves and everything else as being governed by the descriptions we obtain from these observations/measurements.
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