Challenges of Quantum Physics

Even if Einstein’s basement level of physical law is not discovered, allowing for an expansion of Newtonian physics that could encompass all size scales, the question of whether or not physical events are “determined” requires that we define the concept “determined.” If it means that physical events at very small scales cannot be predicted by humans, except in some probabilistic sense, then it is still possible to claim that these events are nevertheless determined by the particles (and photons) in accordance with laws that govern the particles, even though humans can’t figure out how these things happen. This form of “strict determinism” is the simplest mental model for understanding reductionism.

Even the more traditional view, in which particles behave randomly within probabilistic limits, is compatible with reductionism.  Reductionism does not require that the strict form of determinism be true.  Reductionism merely requires that a physical event that is describable at one “level of physical explanation” be theoretically redundant to a description of the same event at a lower “level of physical explanation.” 

The reader is entitled to object: “Wait a minute! What are ‘levels of physical explanation’ and how did they enter this discussion?”

The matter of “levels of physical explanation” must be dealt with for the reader who is not prepared to accept the existence of a basement level of physical law. Such a reader will insist on the notion, possibly correct, that small scale physical events are inherently probabilistic, and that even a hypothetically complete knowledge of physical conditions at one moment does not guarantee a specific outcome at the next moment. In either case, a discussion of “levels of physical explanation” should be useful to readers of both persuasions.

Levels of Physical Explanation

In the physical sciences it is common to treat a physical process at a “higher level” than atoms interacting in accordance with the most basic level of physical law, a = F/m and quantum physics.  Instead, other “laws” are constructed for everyday settings, either derived from the basic level of laws or derived from experiment and deemed compatible with the basic laws. Two examples will serve to illustrate this.

First, consider the atmosphere, which consists of an immense number of molecules. Any thought of using a = F/m applied at the level of molecules for the purpose of predicting the weather would be silly. It would be a silly idea because of its impracticality, for not only is there no way to know the position and velocity of all the molecules in the atmosphere at a given time for establishing the "initial conditions" required for subsequent calculation using a = F/m, but no known computer could perform this arduous calculation for the entire atmosphere.  Rather, the meteorologist employs a “higher level of physical explanation” by inventing “laws” that govern aggregate properties. Examples of aggregate properties are "atmospheric pressure," “temperature,” "wind speed" and “coriolis force” (not a force at all, but a handy invention).  Each of these constructions simplifies the task of getting a job done. These higher level properties are useful to the forecaster, and they are useful to the atmospheric scientist trying to understand atmospheric behavior.

In each case the invented property and rules for using it can be derived from a = F/m, so these handy properties and rule for usage are “emergent properties” of the basic level of physical laws. Every atmospheric scientist would acknowledge that whenever a meteorologist relies on a handy rule, such as “wind speed is proportional to pressure gradient,” what is really occurring in the atmosphere is the unfolding of an immense system of particles obeying a = F/m. 

Just because scientists find it useful to employ "emergent properties" does not mean that the emergent properties exist; rather, they are no more than a useful tool for dealing with a complex system. A "pressure gradient" doesn't exist in nature; it exists only in the minds of humans. Model idealizations of an atmosphere can be used to prove, using a = F/m, that the thing called a "pressure gradient" is associated with wind, but these very proofs belie the existence of the concept, for they "invent" the concept of a pressure gradient for use in a model that then uses a = F/m for aggregations of molecules to calculate aggregate air motions which show that these motions should be associated with the invented property called "pressure gradient."  The handy meteorology rules, and their "emergent property" tools, are fundamentally redundant to a = F/m.

The second example of a “higher level of physical explanation” involves table salt.  Sodium and chlorine atoms combine to form NaCl molecules, which under certain conditions can form a solid crystal that we know in everyday life as common table salt. The formation of the NaCl molecule, and its arrangement into a crystal, are due to simple electrical forces that can be understood using quantum physics and a = F/m. Only molecules that have a specific symmetry of electrical fields will form crystals when they are close to each other.

The regular spacing of NaCl molecules, forming a 3 dimensional lattice, is an "emergent property" of solid salt, and is an inherent outcome of our quantum physics and a = F/m understanding of how particles interact. Even though the lattice structure of a salt crystal is not the most basic level for understanding things, it can be a far more convenient starting point for an investigation of other properties of the material than the most basic level of physical laws; but this does not invalidate the position that everything about a salt crystal is the result of an unfolding of basic physical laws upon an immense number of particles.

Returning to the issue of whether quantum physics requires that phenomena within an atom be strictly determined versus probabilistic, the reductionist position is that a resolution of this matter is unnecessary since in either case phenomena at higher levels of explanation can, in theory, be reduced to events governed by the basic level of physical laws:  a = F/m and quantum physics.  This is a true statement regardless of one’s belief on the determinate or probabilistic nature of quantum physics.

The refinements of modern physics do not detract from the central concept of materialism, which is that everyday (large-scale) phenomena are the result of the mindless interaction of a myriad of tiny particles in accordance with invariant laws of physics. Reductionists acknowledge the importance of the many levels for explaining complex phenomena, but they insist that all levels higher than the basic level of physical explanation are fundamentally “unreal” and superfluous, even though the higher level of explanation may remain more “useful” than a lower level of explanation.

Science embraces what might be termed the "first law of reductionism," that whenever a phenomenon can be explained by recourse to a more basic level of physical law, the “higher level” explanation should only be used when it is drastically simpler to use and unlikely to be misleading. Whenever a higher level of explanation is used, there should be an acknowledgement that it is being used for convenience only.

Living Systems

Reductionism views "mind" as an "emergent property" of complex living systems, resulting from the complex interaction of electrons, protons, etc. "Thoughts, emotions, intentions" and other everyday mental phenomena are technically superfluous concepts for anyone wishing to explain ultimate causes for events, since physics makes a good case for being able to conceptually account for the entire unfolding motion of particles that compose the material world, including those particles that constitute a brain.

Such things as "thoughts, emotions and intentions" are mental constructions of the brain that in everyday situations are more "useful" than the laws of physics.  But, as useful as they are, since they are not actually causing the movement of particles in the living organism, it can be said that they don't exist at the most fundamental level of understanding.  Even “free will” must be shorn of its essential features, and recast as another "emergent" product of real causes. 

It should go without saying, but I will say it anyway, that Reductionism has no place for magic, spirits, mysticism, prayer and God, and relegates them to a category of "non-existent" products of mental activity which may have been adaptive (for the genes) at some time in the human evolutionary past.

Consciousness is an emergent phenomenon, just as the "wind" is an emergent phenomenon. The person who prefers to employ the higher level concept “wind” instead of dealing with an immense number of molecules can be excused on the grounds that “wind” is a tractable concept for getting a job done whereas an immense number of molecules subject to a = F/m is not tractable. A psychologist can likewise be excused for preferring the concept “consciousness” over an elaborate theory of interconnected neurons. It would therefore be unwise to object to the use of “consciousness” on the basis that it is superfluous and non-existent. Consciousness and the wind are both superfluous and non-existent, technically speaking, but they are useful emergent phenomena. 

The reader may balk at extrapolating emergent phenomena in physical systems to living organisms. Nevertheless, a living organism IS a physical system, and the movement of particles in a living system is just as determined by physical laws as are the movements of molecules in the atmosphere. This is the essence of “levels of physical explanation” and "emergent phenomena" as viewed by a reductionist.

I claim that the entire scientific enterprise is "reductionist" since the goal of scientific investigations is to "reduce" an observed phenomenon to a simpler phenomenon by employing the laws of physics. This “reduction” to a lower level of physical explanation can be done explicitly, or it can be done implicitly by presenting a principle that might achieve the explanation at the lower level. The following exercise illustrates a way to implicitly disprove the existence of free will (as it is commonly understood), prayer, guardian angels, God, the Devil, or any other weird entity.


Figure A.01. What's wrong with this diagram? The arrows indicate a few of the forces "felt by" the central proton. These forces exist because of nearby particles. Physics 101 teaches that there are only 4 forces that influence the motion of particles:  gravity, electromagnetism, and the nuclear and weak forces. (In this figure I don't bother listing the nuclear and weak forces; they are unimportant for all scales larger than atomic ones.)  If other forces existed then laboratory experiments would show particles departing from expected motions and this would then allow for the existence of mysterious other forces to be postulated, such as the ones indicated in the figure. However, all well‑controlled experiments to date can be accounted for by invoking no more than the 4 known forces of nature, so the "hard core reductionist" concludes that such things as God, prayer, free will etc. are "emergent" properties of complex living systems of particles, best described as "existing" only at a redundant “higher” level of understanding. 

Recall that Newtonian physics employs the equation a = F/m to describe the motions of particles, where a is the acceleration of a particle, F is the sum of forces acting upon it, and m is the particle's mass. For a system of N particles, each particle "feels" (its motion is influenced by) the other N-1 particles, according to:  a = (F1 + F2 + F3 + ... FN-1)/m, where each F is the sum of the 4 force types (gravity, electromagnetism, etc.). In the real world, where the number of particles is astronomical, N is so large that it is theoretically impossible to perform such a calculation (though it can still be imagined as a "thought experiment"). Classical physics is a paradigm for understanding the universe of particles as an immense pinball machine, or billiard table, with the exception that the balls interact in more complicated ways than merely bouncing off each other elastically when they "hit." But this mental picture was a necessary early step in comprehending the world, and for the bulk of science it is a sufficient paradigm.

As the diagram in Fig. 1.01 implies, there's no room for “will” or “prayer” or even "God" since these things would have to conjure forces in a way that leads to desired "emergent property" outcomes for not just one particle, but an immense number of particles.  This is a preposterous idea!  

Who would deny that living things are made up of the same electrons, protons, etc that constitute inanimate things? And is it not a conservative assertion to assume that electrons and protons found in animate objects are moved by natural forces, and in accordance with the same a = F/m law, that applies to electrons and protons found in inanimate objects?

This is a profound assertion! If a person's brain is made up of electrons and protons that obey a = F/m, then the brain is a "mechanism." It changes state in accordance with the same basic laws of nature that control a machine. The brain is immensely complicated, and masks the fundamental simplicity of what is happening inside; the particles within are moved by the same forces that move simple systems; and it is moved by no other forces! 

If this is true, then "free will" must be an illusion. Schopenhauer captured the essence of this idea when he wrote "A man can surely do what he wills to do, but he cannot determine what he wills." Nevertheless, by carefully defining "free will" it should be possible to rescue the essential idea of free will from reductionism.  The only way I can imagine saving some semblance of meaning for “free will” is to define it carefully, such as: “free will is the perception that events happen differently after experiencing a resolve to influence future events.” This is a tricky definition, for it retains some of the every day feeling of what we refer to by the term, yet it is cleverly compatible with reductionism. Our vision of future events prior to experiencing a resolve to act fails to take into account the impending resolve. Moreover, our imagined vision of the future is based on incomplete and always flawed information.  Since the problem of free will is a concept at a very “high level of explanation” it is unlikely to engage reductionist thinkers.

Whenever an experiment is conducted that enables the forces upon a particle to be evaluated, the particle's movement is observed to obey a = F/m. This is true when the particle is a simple subatomic particle, like an electron or proton, and also when the particle is more complicated, like an atom, molecule or group of molecules. There is every reason to believe that a = F/m is true for ever more complicated arrangements of particles, since any configuration of particles can be viewed as a system of many simple configurations ‑ for which we have confidence that a=F/m applies. 

It has been argued that the physicist exhibits "faith" in extending what is observably true in simple settings to more complicated ones. This assertion of faith is true, but the faith follows from the physicist's desire to invoke a minimum of assumptions for any explanation. Adopting a = F/m for simple situations is an assumption which works, and extending it to more and more complicated situations is an additional assumption; but this path to explanations is a "minimum assumption" path, and it has survived every challenge.

Some Practical Considerations Concerning Levels of Explanation 

The brain evolved, like every other organ, to enhance survival of the genes that encode for its assembly. It should be no surprise, therefore, to find that it is an imperfect instrument for comprehending reality. If it is more efficient to construct brain circuits for dealing with the world using concepts such as spirits and prayer, rather than reductionist physics, then the "forces of evolution" can be expected to select genes that construct brain circuits that employ these pragmatic but false concepts. Since no tasks pertaining to survival require the a = F/m way of thinking, the brain will find this to be a difficult concept. It is a triumph of physics to have discovered that a = F/m and quantum physics rule everything!

How might someone who embraces reductionism be affected by it? Does reductionism have any practical uses? 

A reductionist would reject suggestions that are clearly incompatible with reductionism. This sounds straightforward, but it has a subtle meaning. Entire categories of "explanation" fail to satisfy the reductionist requirement. To say that the wind is the action of the "wind spirit" is simply a non‑explanation. Not only does it call for an explanation of what the wind spirit is, and how it came to be, etc, it is totally unnecessary. There will always be a simpler explanation, such as "a high pressure system is located to our north and the air is flowing away from it, toward a neighboring low pressure region." This explanation, in its turn, can theoretically be simplified by invoking the physical chemistry concepts embodied in the perfect gas law equation PV=nRT (pressure, volume, number of moles of gas, Rydberg constant, and temperature). This equation in turn can be simplified even further by invoking a = F/m, which in fact is used in deriving PV=nRT. Thus, the reductionist can, in theory, "reduce" a phenomenon high in the conceptual hierarchy to those at the lowest level in the hierarchy. Any hypothetical explanation that is hopelessly incapable of being reduced to basic physical laws deserves rejection.

It is important to understand that if a person "chooses" to remain at the most basic level of physical explanation, where only a = F/m and quantum physics explanations can be invoked, then the concepts of P, V, n, R and T, for example, are superfluous, and while thinking at this level the concepts don't exist!  But if a person chooses to view the world at a next higher level, he will invoke PV=nRT, define the terms (pressure is the force per unit area per unit time caused by momentum change of particles bouncing off a surface, temperature is the average kinetic energy of the population of particles, etc), and proceed without explicit use of a = F/m. A meteorologist will want to go one level higher and make use of pressure gradients, coriolis force (a fictitious force that makes things easier to work with), eddy diffusion coefficients, etc. For him, there is no explicit use of a = F/m, nor of PV=nRT, yet all such concepts are inevitable consequences of a = F/m.  Notice that whichever level is chosen, all concepts at higher levels are redundant, and non‑existent (for as long as thought remains at the lower level). 

Whereas I chose examples in the atmospheric sciences, the concepts apply to all other sciences. In the life sciences, for example, a next higher level might be that of the molecular biologist. He works with strands of long molecules called RNA and DNA. It is useful to think of these long molecules as consisting of sequences of the nucleotides thymine, cystosine, adenine, guanine and uracil. Laws at this level specify that cytosine only pairs with guanine (and visa versa) in forming a DNA molecule, etc. No explicit use is made of a = F/m, but notice also that the molecular biologist also has no use for such concepts as "consciousness" or "free will." These and other higher level concepts are redundant, and don't exist, while remaining at the molecular biology level of understanding living phenomena.

At an even higher level in the life sciences, consider the neuropsychologist. He wants to know where nerve cells in the brain connect, and which hormones are released by a gland when activated by a specific nerve signal, etc. He does not make explicit use of a = F/m, or DNA, or most other molecular biology concepts. For the neuropsychologist, such concepts as "free will" and "consciousness" seem forever appealing yet elusive. This is because free will and consciousness are concepts that belong to a higher level, psychology. The neuropsychologist should not invoke these higher level concepts to give an account of phenomena observed at the neuropsychology level. If he tries to invoke them, he is attempting to bridge levels, and this task is fraught with pitfalls. 

I do not object to the use of higher level concepts provided the user is mindful of the concept’s place in the hierarchy of levels of explanation. A scientist must always be aware that these many levels exist, and he should be prepared to view a problem from the next lower level if that is feasible, and even the next higher level if the problem seems otherwise intractable.

A naive person might believe that the primitive person, viewing everything in terms of spirits, is thinking at a higher level than the scientist. This would be a ludicrous belief. A primitive is a lazy and unsophisticated thinker. He is totally oblivious to reductionist "levels of thought." As I will describe later, he uses a brain part that is incapable of thinking rationally: the right prefrontal cortex. Human evolution's latest, and possibly most magnificent achievement, is the left prefrontal cortex, which evolution uses to usurp functions from the right prefrontal cortex when rational thought is more appropriate (i.e., feasible). Too often contemporary intellectuals will unthinkingly succumb to the pull of primitive thought, as when someone proudly proclaims that they are “into metaphysics" (an oxymoron). 

A fuller exposition of this topic cannot be given without a background of material that will be presented in later chapters. For now, I will merely state that mysticism is a natural way of thought for primitive humans. It is "easier" for them to invoke a "wind spirit" explanation than the reductionist ones, such as a = F/m, or higher level derivative physical concepts. They do this without realizing how many ad hoc assumptions they are creating, which in turn require explanations, and this matter is never acknowledged (as with invoking God as an explanation, without explaining "God"). Their thinking may seem acceptable from the standpoint of a right prefrontal cortex (or "efficient" from the perspective of the genes that merely want to create a brain that facilitates the gene's "goal" of existing in the future), but it is terribly misguided from the standpoint of the thinker endowed with a functioning left prefrontal cortex, that demands rational explanations with a minimum of assumptions. This unthinking proliferation of ad hoc assumptions bothers the reductionist, but it doesn't bother the unsophisticated primitive.

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