QUANTUM MECHANICS : THEORIES OF CONSCIOUSNESS (Part1)

QUANTUM MECHANICS : THEORIES OF CONSCIOUSNESS 

(Part1)

Quantum mechanical theories of consciousness are contrasted to classical ones. A key difference is that the quantum laws are fundamentally psychophysical and provide an explanation of the causal effect of conscious effort on neural processes, while the laws of classical physics, being purely physical, cannot. The quantum approach provides causal explanations, deduced from the laws of physics, of correlations found in psychology and in neuropsychology.

Introduction

Isaac Newton initiated in the seventeenth century an approach to understanding nature that, with important contributions from Clerk Maxwell and Albert Einstein, developed into what is called classical mechanics. That theory is now known to be fundamentally incorrect. It was replaced around 1926 by a profoundly different theory called quantum mechanics. A principal conceptual difference between classical mechanics and its quantum successor is that the former is exclusively physical whereas the latter is essentially psychophysical. In particular, classical mechanics is theory of a material physical world conceived to be completely specified by numbers assigned to points in space and time, and to be, moreover, dynamically complete, in the sense that the behavior of these numbers for all times is completely specified by laws and initial conditions that involve only these numbers themselves. Contrastingly, orthodox quantum mechanics brings into the dynamics certain conscious choices that are not determined by the currently known laws of physics but have important causal effects in the physical world.   

The entry of these causally efficacious conscious choices into contemporary physics has led some quantum physicists to believe that an adequate scientific theory of the conscious brain must be quantum mechanical. This view is challenged by some non-physicists, who argue that quantum theory deals with microscopic atomic-level processes whereas consciousness is associated with macroscopic neuronal processes, and that the concepts of classical physics provide an adequate understanding of such macroscopic systems.

That argument is not valid. Quantum mechanics deals with the observed behaviors of macroscopic systems whenever those behaviors depend sensitively upon the activities of atomic-level entities. Brains are such systems Their behaviors depend strongly upon the effects of, for example, the ions that flow into nerve terminals. Computations show that the quantum uncertainties in the ion-induced release of neurotransmitter molecules at the nerve terminals are large (Stapp, 1993, p.133, 152). These uncertainties propagate in principle up to the macroscopic level. Thus quantum theory must be used in principle in the treatment of the physical behavior of the brain, in spite of its size.   

The entry into quantum dynamics of experiential elements, and in particular of our conscious choices, is rendered possible by the effective elimination from quantum mechanics of the classical concept of material substance. Quantum theory retains the core feature of classical physics, namely a structure of mathematical quantities assigned to points in space and time. But both the behavior and the significance of this structure is greatly altered. The mathematical structure represents no longer a classically conceived material universe but rather an informational structure that represents, in effect, the knowledge associated with psychophysical events that have already occurred, and also certain objective tendencies (propensities) for the occurrence of future psychophysical events This conceptual revision is epitomized by the famous pronouncement of Heisenberg (1958, p.100):

“The conception of objective reality of the elementary particles has thus evaporated not into the cloud of some obscure new reality concept but into the transparent clarity of a mathematics that represents no longer the behavior of particles but rather our knowledge of this behavior.”

   

The aim of this chapter is to explain briefly, in plain words, how this enormous change came about, how it works, and how this altered conception of the role of consciousness in physics impacts on psychology and neuroscience.

Origin of quantum mechanics

Quantum mechanics was initiated by a discovery made by Max Planck in 1900. Planck was studying the distribution over frequencies of the radiant energy emitted from a tiny hole in a hollow container. Classical physics gave clear predictions about the dependence of this energy distribution upon the temperature of the container, but those predictions did not match the empirical facts.

Planck found that the empirical data could be accounted for if one assumed that the radiant energy associated with each given frequency was concentrated in units, or quanta, with the amount of energy in a unit being directly proportional to the frequency of the radiation that carried it. The constant of proportionality was measured by Planck, and is called Planck’s constant.

This discovery was followed by a flood of empirical data that tested various predictions of classical physics that depended sensitively on the classical conceptions of such things as electrons and electro-magnetic radiation. The data revealed fascinating mathematical structures, which seemed to involve Planck’s constant, but, like Planck’s data, was essentially incompatible with the classical materialist conception of the world.

Many of the best mathematicians of the generation, men such as Hilbert, Jordan, Weyl, von Neumann, Born, Einstein, Sommerfeld, and Pauli, struggled to unravel this mystery, but it was not until 1925 that the key step was made. Heisenberg found that correct predictions could be obtained if one transformed classical mechanics into a new theory by a certain “quantization” procedure. This procedure replaced the numbers that specified the structure of the classically conceived material universe by actions. Actions differ from numbers in that the ordering of numerical factors does not matter---2 times 3 is the same as 3 times 2---whereas the order in which two actions are applied can matter.

Problems of interpretation

This replacement of numbers by actions is the mathematical foundation of quantum mechanics. But an adequate physical theory requires more than just mathematical rules. It requires also a conceptual framework that allows certain mathematical statements to be tied to human experiences. In classical mechanics the interpretive framework that ties the mathematics to experience does not disturb the mathematics. It envelops the mathematical structure but does not affect it.  The basic idea of the classically conceived connection between the physically and psychologically described aspects of nature is a carry-over from the planetary dynamics that was the origin of classical mechanics: the locations of objects are regarded as being directly knowable, without producing any effects on those objects. But in quantum mechanics the numbers that in classical mechanics represent, for example, the locations of various material objects are replaced by actions. These actions are associated with the process of acquiring information or knowledge pertaining to the location of that object, and this action normally affects the state that is being probed: the act of acquiring knowledge about a system becomes entangled in a non-classical way with the information-bearing quantum mechanical state of the system that is being probed.

This elimination of the numbers that were imagined to specify the physical state of the material world, and their replacement by actions associated with the acquisition of knowledge, raises huge technical difficulties. The needed conceptual adjustments were worked out principally by Bohr, Heisenberg, Pauli, and Born. The center of this activity was Bohr’s institute in Copenhagen, and the conceptual framework created by these physicists is called The Copenhagen Interpretation. 

The Copenhagen interpretation

A key feature of the new philosophy is described by Bohr:

In our description of nature the purpose is not to disclose the real essence of phenomena but only to track down as far as possible relations between the multifold aspects of our experience.  (Bohr, 1934, p.18)

...the appropriate physical interpretation of the symbolic quantum mechanical formalism amounts only to prediction of determinate or statistical character, pertaining to individual phenomena appearing under conditions defined by classical physics concepts. (Bohr, 1958, p.64).

The references to `"classical physics concepts'' are explained as follows:

...it is imperative to realize that in every account of physical experience one must describe both experimental conditions and observations by the same means of communication as the one used in classical physics. (Bohr, 1958, p.88).

The decisive point is to recognize that the description of the experimental arrangement and the recording of observations must be given in plain language suitably refined by the usual physical terminology. This is a simple logical demand since by the word “experiment” we can only mean a procedure regarding which we are able to communicate to others what we have done and what we have learnt (Bohr, 1958, p 3)

Bohr is saying that scientists do in fact use, and must use, the concepts of classical physics in communicating to their colleagues the specifications on how the experiment is to be set up, and what will constitute a certain type of outcome. He in no way claims or admits that there is an actual reality out there that conforms to the precepts of classical physics.

But how can one use jointly and consistently these two mutually inconsistent descriptions of nature? That is the problem that the Copenhagen Interpretation solves, at least for all practical purposes.

Quantum dualism

The Copenhagen solution is to divide nature into two parts. One part is the observing system, including the bodies, brains, and minds of the human beings that are setting up the experimental situations and acquiring, via experiential feedbacks, increments in knowledge. This observing part includes also the measuring devices.  This observing system is described in ordinary language refined by the concepts of classical physics. Thus the agent can say “I placed the measuring device in the center of the room, and one minute later I saw the pointer swing to the right.” The agent’s description is a description of what he does---of what probing actions he takes---and of the experienced consequences of his actions. The descriptions in terms of the language and concepts of classical physics are regarded as part of this first kind of description.

The other part of nature is the system being probed by the classically conceived and described observing system. This probed system is described in the symbolic language of quantum mathematics.

In classical physics the classical concepts are asserted to be applicable in principle right down to the atomic level. But according to the quantum precepts the quantum mathematical description must be used for any properties of the atomic entities upon which observable features of nature sensitively depend.

This separation between the two parts of nature is called the Heisenberg cut. Above the cut one uses experience-based classical descriptions, while below the cut one uses the quantum mathematical description.

The cut can be moved from below a measuring device to above it. This generates two parallel descriptions of this device, one classical and the other quantum mechanical. The quantum description is roughly a continuous smear of classical-type states. The postulated theoretical correspondence, roughly, is that the smeared out mathematical quantum state specifies the statistical weights of the various alternative possible classically described experienceable states. The predictions of the theory thereby become, in general, statistical predictions about possible experiences described in the conceptual framework of classical physics.

There is, however, a fly in the ointment: In order to extract statistical predictions about possible experiences, some specific probing question must be physically posed. This probing question must have a countable set of experientially distinct alternative possible responses. “Countable” means that the possible responses can be placed in one-to-one correspondence with the whole numbers 1, 2, 3, …, or with some finite subset of these numbers. But the number of possible classically describable possibilities is not countable: there is a continuous infinity of such possibilities. So some decision must be made as to which of the possible probing questions will be physically posed.

Conscious choices

The mathematical structure of the theory does not specify what this question is, or even put statistical conditions on the possibilities. Thus the mathematical theory is dynamically incomplete on three counts: it fails to specify which probing question will be posed, when it will be posed, and what response will then appear. The theory does, however, assign a statistical weight (probability) to each of the alternative possible responses to any question that could be posed.

 

Von Neumann gave the name Process 1 to the physical posing of a probing question. He specified its general mathematical form, and sharply distinguished it from the very different Process 2, which is the mathematically specified evolution of the quantum state in accordance with the rules specified by the quantization procedure. Process 1 events intervene abruptly, from time to time, in the orderly evolution specified by Process 2.

How does orthodox Copenhagen quantum theory resolve this critical problem of the mathematical indeterminateness of the choices of the needed Process 1 probing actions?