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- Henry P. Stapp, Philosophy of Mind and the Problem of Free Will in the Light of Quantum Mechanics.Arguments pertaining to the mind-brain connection and to the physical effectiveness of our conscious choices have been presented in two recent books, one by John Searle, the other by Jaegwon Kim. These arguments are examined, and it is explained how the encountered difficulties arise from a defective understanding and application of a pertinent part of contemporary science, namely quantum mechanics. The principled quantum uncertainties entering at the microscopic levels of brain processing cannot be confined to the micro level, but percolate up to the macroscopic regime. To cope with the conflict between the resulting macroscopic indefiniteness and the definiteness of our conscious experiences, orthodox quantum mechanics introduces the idea of agent-generated probing actions, each of which specifies a definite set of alternative possible empirically/experientially distinguishable outcomes. Quantum theory then introduces the mathematical concept of randomness to describe the probabilities of the various alternative possible outcomes of the chosen probing action. But the agent-generated choice of which probing action to perform is not governed by any known law or rule, statistical or otherwise. This causal gap provides a logical opening, and indeed a logical need, for the entry into the dynamical structure of nature of a process that goes beyond the currently understood quantum mechanical statistical generalization of the deterministic laws of classical physics. The well-known quantum Zeno effect can then be exploited to provide a natural process that establishes a causal psychophysical link within the complex structure consisting of a stream of conscious experiences and certain macroscopic classical features of a quantum mechanically described brain. This naturally created causal link effectively allows consciously felt intentions to affect brain activity in a way that tends to produce the intended feedback. This quantum mechanism provides an eminently satisfactory alternative to the classical physics conclusion that the physical present is 1 completely determined by the physical past, and hence provides a physicsbased way out of the dilemma that Searle and Kim tried to resolve by philosophical analysis..
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A simple exactly solvable model is given of the dynamical coupling between a person’s classically described perceptions and that person’s quantum mechanically described brain. The model is based jointly upon von Neumann’s theory of measurements and the empirical findings of close connections between conscious intentions and synchronous oscillations in well separated parts of the brain. A quantum-Zeno-effect-based mechanism is described that allows conscious intentions to influence brain activity in a functionally appropriate way. The robustness of this mechanism in the face of environmental decoherence effects is emphasized.
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René Descartes proposed an interactive dualism that posits an interaction between the mind of a human being and some of the matter located in his or her brain. Isaac Newton subsequently formulated a physical theory based exclusively on the material/physical part of Descartes’ ontology. Newton’s theory enforced the principle of the causal closure of the physical, and the classical physics that grew out of it enforces this same principle. This classical theory purports to give, in principle, a complete deterministic account of the physically described properties of nature, expressed exclusively in terms of these physically described properties themselves. Orthodox contemporary physical theory violates this principle in two separate ways. First, it injects random elements into the dynamics. Second, it allows, and also requires, abrupt probing actions that disrupt the mechanistically described evolution of the physically described systems. These probing actions are called Process 1 interventions by von Neumann. They are psycho-physical events. Neither the content nor the timing of these events is determined either by any known law, or by the afore-mentioned random elements. Orthodox quantum mechanics considers these events to be instigated by choices made by conscious agents. In von Neumann’s formulation of quantum theory each such intervention acts upon the state of the brain of some conscious agent. Thus orthodox von Neumann contemporary physics posits an interactive dualism similar to that of Descartes. But in this quantum version the effects of the conscious choices upon our brains are controlled, in part, by the known basic rules of quantum physics. This theoretically specified mind-brain connection allows many basic psychological and neuropsychological findings associated with the apparent physical effectiveness of our conscious volitional efforts to be explained in a causal and practically useful way..
In the context of theories of the connection between mind and brain, physicalism is the demand that all is basically purely physical. But the conception of “physical” embodied in this demand is characterized essentially by the properties of the physical that hold in classical physical theories. Certain of those properties contradict the character of the physical in quantum mechanics, which provides a better, more comprehensive, and more fundamental account of phenomena. It is argued that the difficulties that have plagued physicalists for half a century, and that continue to do so, dissolve when the classical idea of the physical is replaced by its quantum successor. The argument is concretized in way that makes it accessible to non-physicists by exploiting the recent evidence connecting our conscious experiences to macroscopic measurable synchronous oscillations occurring in wellseparated parts of the brain. A specific new model of the mind-brain connection that is fundamentally quantum mechanical but that ties conscious experiences to these macroscopic synchronous oscillations is used to illustrate the essential disparities between the classical and quantum notions of the physical, and in particular to demonstrate the failure in the quantum world of the principle of the causal closure of the physical, a failure that goes beyond what is entailed by the randomness in the outcomes of observations, and that accommodates the efficacy in the brain of conscious intention.
A criterion for the existence of human free will is specified: a human action is asserted to be a manifestations of human free-will if this action is a specific physical action that is experienced as being consciously chosen and willed to occur by a human agent, and is not determined within physical theory either in terms of the physically described aspects of nature or by any non-human agency. This criterion is tied to the structure of a physical theory. It is noted that the orthodox quantum mechanics that flows from John von Neumann’s analysis of the process of measurement in quantum theory is described in terms of three processes that are effectively based on a three-level conception of reality. Von Neumann’s “Process 2” is the deterministic evolution, via the Schroedinger equation, of a physically described aspect of reality, the quantum state. His “Process 1” is the physically described aspect of a psychophysical probing action whose psychologically described aspect is an increment in the knowledge of a probing agent/observer. Process 3, in Dirac’s words, is “a choice on the part of nature” of the response to such a probing action. It is argued here that all three levels of this quantum structure, the physically described quantum state, the probing knowledge-acquiring agents, and the response-choosing nature, are all best conceived as idea-like in character. Quantum mechanics, though puzzling when viewed from the inappropriate perspective of the mechanistic classical physics, becomes rationally coherent when the underlying reality is conceived to be not a physically described classical monism, but rather an ideabased quantum triality. This idea-based conception of reality evades the pitfalls of nonphysics-based idealism by being erected directly upon the basic concepts of pragmatic empirically validated quantum mechanics. However, the dynamical structure of quantum theory contains certain causal gaps..
Discussion of Henry P. Stapp, Philosophy of Mind and the Problem of Free Will in the Light of Quantum Mechanics
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