Neutral monism, perspectivism and the quantum dualism: An essay
aa r X i v : . [ phy s i c s . h i s t - ph ] J u l Neutral monism, perspectivism and the quantum dualism:An essay
Badis YdriDepartment of Physics, Annaba University,Annaba, Algeria.July 10, 2020
Abstract
Quantum mechanics in the Wigner-von Neumann interpretation is presented. This ischaracterized by 1) a quantum dualism between matter and consciousness unified withinan informational neutral monism, 2) a quantum perspectivism which is extended to a com-plementarity between the Copenhagen interpretation and the many-worlds formalism, 3) apsychophysical causal closure akin to Leibniz parallelism and 4) a quantum solipsism, i.e.a reality in which classical states are only potentially-existing until a conscious observationis made.
Contents A revamping of the Wigner-von Neumann interpretation [1, 2] is presented which involvesin an essential way i) perspectivism [3] and quantum logic [4] and ii) naturalistic dualism [5](quantum matter and classical consciousness are distinct aspects of a more neutral substance,i.e. neutral monism).The resulting quantum dualism involves an extension of Bohr’s complementarity [6] to aprinciple of complementarity between the local first-person subjective observers of the Copen-hagen interpretation and the global third-person objective observers of the many-worlds for-malism.The collapse of the wave function (which is tied to the arrow of time and a comptabilisticaccount of free will) is seen as a psychophyscial force connecting the physical and mentalsimilar (but acts in opposite direction) to the psychophysical force producing qualia. Therelation between the physical and the mental is modeled on the many-minds interpretation [7]producing therefore a mental causation similar to Leibniz parallelism (see [10] and referencestherein).This form of causation produces also a weaker form of solipsism consistent with Bell’stheorem [11,12]. Indeed, it is argued that this quantum dualism is characterized by an apparentsubjective idealism (solipsism) in which the consciousness of the first-person observer causesthe potentially-existing classical (pointer) states to actualize only in the sense of psychophysicalparallelism.In summary, this effective quantum dualism (with its fundamental description as an infor-mational neutral monism) is quite different from both the classical Cartesian dualism [13]andthe classical Spinozian neutral monism [14]. It seems to avoid the two main problems of classicalphysicalism [15]: i) the problem of mental causation (many-minds formulation and psychophys-ical parallelism) and ii) the hard problem of consciousness (naturalistic dualism). However, thissingle-world quantum dualism is dual (in virtue of quantum perspectivism) to a pure physical-ism in a many-worlds where the Heisenberg cut [23] is placed at infinity, unitarity is the onlylaw and there is no collapse.
The Schrodingers cat experiment [16] is perhaps the most illuminating thought experimentwhich can be used to delineate precisely what the measurement problem in quantum mechanicsreally is. The physical system under consideration consists of a radioactive atom plus a catenclosed within the wall of a room together with a first-person observer called Schrodingerstanding outside the room.A third-person observer (let us call him Wigner) is standing outside a larger room whichencapsulates the Schrodinger’s cat experiment, i.e. we are in fact considering a variant of thell rights reserved to Badis Ydri Wigner’s friend experiment [17] where Schrodinger plays effectively the role of the friend.A typical quantum process consists then of the following four stages:1. The initial state of the observer outside the room is | happy i , of the cat inside the roomis | alive i and of the radioactive atom is | undecayed i .2. After one hour there a fifty percent chance that the radioactive atom will decay thusactivating a mechanism which releases a poison that kills the cat instantly. The states ofthe system radioactive atom+ cat after one hour is given therefore by the entangled state | ψ i = 1 √ | i + | i ) . (2.1)Where | i = | alive i| undecayed i , | i = | dead i| decayed i . (2.2)The entangled state | ψ i means that a microscopic event (the decaying of the radioactiveatom) is amplified to a macroscopic event (the life or death of the cat) thus the linearsuperposition principle which is known to be experimentally satisfied in all quantumsituations is transferred to classical scales where only one branch of the wave function isobserved to be realized at any one time. Indeed, the cat can be thought of as performinga measurement on the atom and finding it decayed and hence the cat dies in one branch ofthe wave function or finding it undecayed and hence the cat survives in the other branchof the wave function.3. In the third stage the observer (Schrodinger) makes his measurement on the state of theentangled system atom+cat by entering the room and looking at the cat thus becom-ing himself entangled with it. The complete entangled state is again given by a linearsuperposition of the form (2.1), viz | Ψ i = 1 √ | i + | i ) . (2.3)But the two branches | i and | i are now given by the states | i = | happy i| alive i| undecayed i , | i = | sad i| dead i| decayed i . (2.4)Thus, in the branch | i the observer is happy to see that the cat is alive because theatom did not decay whereas in the other branch | i the observer is sad to see the cat isll rights reserved to Badis Ydri dead because the atom decayed. These two states are maximally entangled and that iswhy the state | Ψ i is called pre-measurement state. Indeed, this pre-measurement statecontains coherence and interference between the branches and the pointer states | i and | i (which form the preferred-basis observed at the classical and macroscopic levels) arestill not actually realized. In fact, these states effectively do not exist before the completedmeasurement [11, 12]. The coherence and interference between the branches can be seenexplicitly from the pure density matrix ρ associated with the pure state | Ψ i given explicitlyby ρ = | Ψ ih Ψ | = 12 | ih | + 12 | ih | + 12 | ih | + 12 | ih | . (2.5)The last two terms are the interference terms and interference, as poignantly stated byFeynman, is the hallmark or even the mother of all quantum behavior.From the perspective of the third-person observer (Wigner) the conscious states (happy,sad) of the first-person observer (Schrodinger) do not effectively exist before reducing thewave function (2.3) in the same way that the states (alive, dead) of the classical cat donot exist until the measurement is completed. Thus, the first-person observer in the pre-measurement state acts in some sense as a philosophical zombie. In the words of Wignerhis friend Schrodinger is ”in a state of suspended animation” before the measurement,i.e. while the superposed state | Ψ i given by (2.3) remains coherent.4. The fourth and last stage is the completed measurement which is described by the reduceddensity matrix ρ r = 12 | ih | + 12 | ih | . (2.6)Thus, the off-diagonal elements responsible for interference are canceled and we end upwith ordinary probabilities for mutual exclusive events, i.e. either the cat is alive or isdead with probability equal one half for each. However, this is a mixed density matrixsince there is no state | Ψ i in the Hilbert space for which ρ r = | Ψ ih Ψ | .The completed measurement is therefore given by the (discontinuous, irreversible, instan-taneous, non-deterministic and non-unitary) transition ρ −→ ρ r . (2.7)This is the collapse or reduction postulate and there is no known process in nature whicheffectuates this transition explicitly. This is the measurement problem. Decoherence [18]tries to effectuate a collapse-like transition by means of a unitary process which couplesll rights reserved to Badis Ydri the system to the environment but this is beside the point since our fundamental workingassumption here is that the above process (2.7) is necessarily non-unitary with respect tothe first-person observer.We have thus two fundamental quantum processes as formulated originally by von Neumannin his book [1]: • Process I which is given by the collapse of the wave function (occurring in stage four). • Process II which is given by the the unitary evolution in time generated by a Hamiltonian H , i.e. it is given by the Schrodinger equation (controlling stages one, two and three).The Copenhagen interpretation is a broad interpretative framework of quantum mechanicsdue originally to Bohr [6] which can be mainly characterized by the assumption that the collapseof the wave function is a genuine independent and fundamental process in nature (a fifth forceof a sort) which is not reducible to any of the other known interactions. This assumption is ofcourse also shared by many other interpretations of quantum mechanics.The weaker assumption that the collapse postulate is an approximation to some more fun-damental unitary law of nature is the main characterization of the many-worlds formalism [19]and similar interpretations. See also [20].These two standpoints are generally taken to be mutually exclusive interpretations of thelaws of quantum mechanics which is quite an unfortunate situation. Indeed, it is always as-sumed either explicitly or implicitly that the collapse of the wave function and the subsequentactualization of the classical states of the cat as seen by the first-person observer (Schrodinger)is a fact in gross contradiction with the branching of the wave function, i.e. the real existenceof a coherent linear superposition of the classical states of the cat as seen by the third-personobserver (Wigner).The central thesis of this essay is precisely the converse claim, i.e. that the Copenhageninterpretation and the many-worlds formalism are not contradictory but they are in fact comple-mentary. The Copenhagen interpretation provides the local perspective of reality whereas themany-worlds provides the global perspective or view of reality. This is similar to the black holecomplementarity principle in which the descriptions given by the asymptotic (Schwarzschild)and infalling observers although they may look contradictory lassically are in fact complemen-tary semi-classically.Thus, a more complete and comprehensive interpretation of quantum mechanics admitsthe collapse of the wave function as a fundamental process of nature brought about by theobservation of first-person local (or simulated as we will discuss in the conclusion) observersbut also admits that the laws of nature are fully unitary, i.e. the branching of the wavefunction and the superposed states are real effect in the world with respect to third-personglobal (unsimulated) observers. It only seems that the world is full of the first kind of observerswho exist in local system of coordinates not allowing them to access easily the full structure ofthe ”curved manifold” of reality. See also Tegmark for example in [21].ll rights reserved to Badis Ydri An independent argument for the complementarity relation between the Copenhagen inter-pretation and the many-worlds formalism is given by the thought experiment considered BySusskind in [22] which involves among other things the properties of entanglement entropy andblack holes.
The observer plays a fundamental role in quantum mechanics. The first-person observers ofthe Copenhagen interpretations (which dominate the world) provide the local view of realitywhile the third-person observers of the many-world formalism provide the global view of reality.Therefore, quantum mechanics is strongly perspectival in character which was formalizedusing the language of quantum logic in [3]. In philosophy, perspectivism is the view due orig-inally to Nietzsche in which it is maintained that all reality is actually perspectival, i.e. thereis no an objective reality out there independent from the knowing subject and free from inter-pretations and perspectives [8] (see also Leibniz and his theory of monads [10]). Perspectivesfor Nietzsche provide an ”optics” of knowledge and they constitute the fundamental conditionof the conscious observer in his search for value and meaning in existence and life. Somewhatmore precisely, perspectivism can be interpreted as a middle position between metaphysicalrealism and relativism akin of Putnam’s internal realism [9].For our purposes, every physical theory is characterized by a certain logic L . For example,the logic of classical mechanics is a Boolean algebra L which is an orthocomplemented dis-tributive lattice based on the power set of the phase space Σ. In other words, Classical events(also called experimental propositions) are subsets of the phase space, pure states semanticallydecide the truth value of experimental propositions, and the corresponding Boolean algebraunderlies Kolmogorovian probability theory.On the other hand, it was shown by Birkhoff and von Neumann in their seminal paper [4] thatthe logic L underlying quantum mechanics is given by the Hilbert lattice of projection operatorson the Hilbert space H which is a non-Boolean, non-distributive and orthocomplemented lattice.Therefore the quantum events (or experimental propositions) are given in this case by closedlinear subspaces of the Hilbert space, i.e. by projection operators while pure states decides thetruth value only probabilistically, and the corresponding Hilbert lattice or logic of projectorsunderlies the standard Born’s rule.The differences between the Boolean algebra of the phase space and the Hilbert lattice ofprojectors stems mostly from the logical disjunction operation OR which in the classical caseis given by the union of subsets of the phase space whereas in the quantum case it is given bythe direct sum of closed linear subspaces of the Hilbert space.The problem of the classical limit in this context is seen as the problem of which projectorsand their corresponding closed linear subspaces will tend in the limit ~ −→ In the classical case there is therefore a single perspective (corresponding to the Booleanstructure of the classical logic) relative to which we can observe every possible measurableproperty of the system but in the quantum case there is no single privileged perspective butinstead there is an intricate web of non-trivially interlocked classical perspectives each of whichcorresponds to a maximal Boolean subalgebra (also called a block) of the Hilbert lattice. Ablock corresponds naturally to a maximal number of compatible and therefore comeasurableobservables which can only be defined locally but not globally. In other words, every block isonly locally measurable, i.e. it can not be defined globally independently of the simultaneousmeasurement of the other blocks.The Hilbert lattice in two dimensions can be viewed as a non-trivial disjoint union (past-ing) of blocks. However, by Gleason’s theorem [24] and its generalization the Kochen-Speckertheorem [25] the Hilbert lattice does not admit in general a Boolean reduction, i.e. there isno a homomorphism from the Hilbert lattice into a Boolean algebra or to a disjoint collection(pasting) of Boolean algebras which is perhaps the best characterization of the measurementproblem. It is worth pointing out that the insistence on the Boolean character is precisely theassumption of reality envisaged by the EPR argument [26].Thus, in quantum mechanics the Hilbert lattice admits a decomposition into maximalBoolean subalgebras or blocks which define an intricate web of non-trivially interlocked clas-sical perspectives. These perspectives are complementarity to each other and their totalitydefines an omni-perspective (which is seeing everything from everywhere as defined by Niet-zsche originally) which is the maximal possible perspective allowed by quantum mechanics.These perspectives are associated naturally with the first-person observers of the Copenhageninterpretation.The perspective of the third-person observer of the many-worlds formalism which sees coher-ent linear superpositions of classical states (such as a dead and alive cats) is a non-perspective(which is seeing everything from nowhere, i.e. a God’s eye view of a sort which is againNietzsche’s terminology) which is logically impossible according to Nietzsche. However, thisimpossibility is simply due as we have seen to the fact that the world is full of first-orderobservers who are not directly aware of coeherent linear superpositions, i.e. consciousness isthrough and through classical which is our second most important thesis in this essay.Hence the complementarity between the many-worlds formalism and the Copenhagen in-terpetation proposed in this essay is nothing else but an extension of Bohr’s complementar-ity principle which holds among first-person observers providing classical perspectives on theworld [6].
The Heisenberg cut [23] which demarcates the boundary between the observer (classical)and the observed (quantum) plays for the first-person Copenhagen observer a role similar tothe role played for the asymptotic Schwarzschild observer by the event horizon (which separatesll rights reserved to Badis Ydri the inside and outside of the black hole). Indeed, the placement of the cut although arbitraryit should be thought of as separating the accessible quantum degrees of freedom (associatedwith the observed physical system or with the entirety of the physical universe) from theinaccessible classical degrees of freedom (those associated with the observer or more preciselywith her consciousness) in the same way that the event horizon separates the accessible degreesof freedom (those outside the horizon) from the inaccessible degrees of freedom (those insidethe horizon). Thus, the fundamental quantum duality proposed in this essay between observerand observed is really a duality between a strictly quantum physical universe and an exactlyclassical consciousness. This is a naturalistic dualism not necessarily a Cartesian one as we willnow elucidate further.The location of the Heisenberg cut is quite arbitrary under the hypothesis of physicalismwhich entails in particular the assumptions i) of material monism and ii) that the physicalworld is causally closed. Indeed, if there is nothing else but the material substance then there isno intrinsic difference between the observer and the observed and the world is strictly causallyclosed. As a consequence there can be no Heisenberg cut and no collapse of the wave function.This picture holds true in the many-worlds formalism. The Heisenberg cut is therefore inexistentwith respect to the hypothetical third-person observers in the same way that for the infallingobserver who is freely falling into the black hole the horizon is no special place in spacetimesince she sees nothing special happening there (equivalence principle). These global third-person observers although they are hypothetical (since they are not directly observed in theworld around us) their existence is fully logical (in contrast to Nietzsche view).However, there is another complementary perspective associated with the realistic local first-person observers of the Copenhagen interpretation and with respect to whom i) there is indeeda fundamental distinction between the observer (classical system) and the observed (quantumsystem) and ii) the collapse of the wave function is a genuine physical effect which is actuallyverified experimentally. See quantum Zeno effect [27, 28].It can be argued in this case, by following von Neumann, that the most natural placementof the Heisenberg cut is the interface between the consciousness of the observer, considered asa different substance, and the physical brain which is a part of the material substance (see forexample [29] and references therein). The degrees of freedom associated with consciousnessare thus constituted of a mental substance (a kind of dark energy which underlies mentalphenomena) which is inaccessible to the first-person observers since the only degrees of freedomwhich can be physically accessed in the usual way by any observer (local or global) must bepart of the material substance. Thus, these degrees of freedom are inaccessible since they lieeffectively behind a horizon (the Heisenberg cut) and therefore they are analogous to the degreesof freedom found behind the horizon of a black hole which are inaccessible to the asymptoticobserver.Physicalism, i.e. the view that everything is reduced to matter and that the world is causallyclosed underlies all of physics including quantum mechanics.But this idea of physicalism (or something near enough as advocated for from a physicalistpoint of view in [15]) is already challenged in the philosophy of mind by many philosophersll rights reserved to Badis Ydri such as Nagel [30] and Chalmers [5].For example, according to Chalmers in his theory of ”naturalistic dualism”, both the usualdegrees of freedom of matter and the degrees of freedom associated with consciousness areequally fundamental and can not be reduced to one another. In this case an appropriateontology is really a double-aspect theory (such as the neutral monism of Spinoza) in which thematerial physical substance and the mental psychological substance are two aspects of a moreneutral and a more fundamental substance which could perhaps be information, i.e. the ”itfrom bit” of Wheeler [31] (see also Sayre [32]). This is therefore a non-reductive theory whichcontains, beside the usual physical laws, psychophysical laws (or further facts) which determinehow the mental arises from the physical. More precisely, subjective experience or qualitativeconsciousness (or qualia) may arise from (caused by) the physical but it is not entailed by thephysical, i.e. it is ontologically distinct and hence it can not be reduced to it.Qualia is the so-called hard problem of consciousness which can not be explained function-ally in contrast with the easy problems of consciousness which according to Chalmers can beexplained functionally or neuronally (lower-level) or cognitively (higher level). This phenomenalconsciousness (also called qualia) is what is associated with the subjective first-person experi-ences (like those of the Copenhagen observers) whereas functional consciousness or awarenessis what is associated with the objective third-person experiences (like those of the many-worldobservers).The role of the third-person observers of the many-worlds formalism seems also to be verysimilar to the role of the philosophical zombies in Chalmer’s theory in the sense that they areboth logically possible although they are not directly seen in nature which means in particularthat qualia, sentience, thought, value and perhaps even intentionality and alike (which involvea first-person experience) require further facts for their explanation.Thus, there exists an explanatory gap as we go from the objective third-person level to thesubjective first-person level of consciousness which can only be accounted for by an effectivetheory of naturalistic dualism which should admit neutral monis as an underlying fundamentaltheory.Physicalism is then challenged by the subjective experiences (which are tied to the existenceof qualia such as color) of first-person conscious observers existing in this world. But physicalismseems also to be challenged by the experiences of these first-person observers, considered withinthe Copenhagen interpretation, who can observe the collapse of the wave function (a fact tiedto the conscious experience of time and comptabilist free will).Indeed, in the same way that neuronal interactions in the brain (themselves due to theinteraction of the brain with the physical system mediated by the environment) give rise tothe subjective experience of color (the redness of the red for example) which is ontologicallydistinct from the brain itself, the interactions of the ontologically distinct degrees of freedomassociated with the consciousness of the observer with the observed physical system (mediatedthrough the brain and then the environment) give rise to the so-called collapse of the wavefunction (dead or alive cat). It appears therefore that the collapse as a (fifth) force works inthe opposite direction of the psychological force producing qualia.ll rights reserved to Badis Ydri By accepting consciousness as ontologically different substance with independent degrees offreedom beside the usual physical particles and fields of the material substance we reach theinescapable conclusion that the Heisenberg cut between the classical conscious observer andthe quantum observed system should be necessarily and naturally placed at the demarcationline between the physical brain and the non-physical mind. At this point, the Cophenhageninterpertation is essentially and effectively reduced to its logical limit which is the Wigner-vonNeumann interpretation also called ”the mind causes collapse” interpretation.The complementarity between the Copenhagen interpretation and the many-worlds formal-ism implies therefore a disitinct dualism (quantum dualism) between consciousness (here in theform of the collapse of the wave function which is caused by the measurement of first-personobservers) and matter (here in the form of the unitary branching of parallel worlds and theirlinear coherent superposition as seen by third-person observers).This is different from Cartesian dualism, shares some common features with naturalisticdualism but really it should be viewed as some form of neutral monism in which reality isconstituted neither of consciousness nor of matter but of a more neutral substance with con-sciousness and matter being two different facets of it (not necessarily the only ones). Thequantum dualism used by the first-person observers existing in this world should also be seenas complementary to the physicalism used by the hypothetical third-person observers of themany-world formalism (who are akin to the philosophical zombies of naturalistic dualism).However, in naturalistic dualism the qualitative consciousness states (color and qualia ingeneral) although ontologically independent of the physical they are produced by a physicalsystem (the brain) but in the quantum dualism it is the classical physical states that are pro-duced (brought from potentiality to actuality) by the ontologically independent consciousnessof the first-person observers (through the collapse) which leads directly to the (far-fetched onthe view of many) proposition of solipsism. The complementarity relation between the Copen-hagen interpretation and the many-worlds formalism is thus translated into a complementarityrelation between solipsism and many-worlds which should be viewed as dual properties.Indeed, if by Bell’s theorem the classical pointer or preferred states of a quantum system donot actually exist (but only exist in potentiality) until a quantum measurement is completed,and if by the Wigner-von Neumann interpretation a quantum measurement requires for itscompletion the free action of a conscious observer, then it follows naturally and logically thatthe degrees of freedom of the consciousness of the observer are responsible for bringing theclassical states from potentiality into actuality which we see as collapse.A somewhat explicit mechanism for the action of consciousness on matter can be given inanalogy with the many-minds interpretation [7] as follows.The hypothetical third-person observer (Wigner) of the many-worlds sees directly the coher-ent linear superposition (2.3), i.e. the superposition of the decayed-atom/dead-cat/sad-observerand undecayed-atom/living-cat/happy-observer (where the ”observer” here refers only to thephysical brain states of the first-person observer).ll rights reserved to Badis Ydri By assuming an infinity of classical mind states, associated with the non-physical degrees offreedom of consciousness, evolving stochastically in time with a probability given by the Born’srule then it is observed that each mind state evolves in a stochastic way to either being attachedto the decayed-atom/dead-cat/sad-observer branch or to the undecayed-atom/alive-cat/happy-observer branch. In other words, the first-person observer (Schrodinger) in the superposition(2.3) becomes fully conscious of the content of the classical state to which it is attached whichappears therefore, from his perspective, as a collapse. This is the sense in which ”consciousnesscauses collapse” which is ultimately due to the fact that the classical mind or consciousness andthe quantum matter both obey Born’s rule which indicates that the underlying fundamentalneutral substance also obeys the Born’s rule. Also, it is not difficult to appreciate that thisform of mental causation is nothing but the Leibnizian psychophysical parallelism [10].Thus, from the perspective of the subjective experiences of the first-person observer it isthe mental degrees of freedom that guide the time evolution of the physical (solipsism of theWigner-von Neumann interpretation) whereas from the fact that quantum mechanics is morefundamental than classical mechanics it is seen that it is the physical degrees of freedom thatguide the time evolution of the mental (third-person observer of the many-worlds). This dualitybetween the two descriptions is of course due to the fact that both the classical mental and thequantum physical obey in this scheme the Born’s rule. But is really quantum mechanics morefundamental than classical mechanics or are they really two independent descriptions of twoontologically distinct substances of nature?An independent argument for ”the mind causes collapse” interpretation is the largely un-derestimated or even underrated Wigner’s friend experiment. Indeed, before Wigner performshis measurement the state | Ψ i of the joint system Schrodinger+cat+atom is given by the max-imally entangled pre-measurement state (2.3). Wigner can surely ask his friend Schrodingerwhether or not he saw a dead cat and then inspect the system cat+atom. The probabilitiesaccording to the Born rule are as follows: • There is a probability 1 / | i of a dead cat. • There is a probability 1 / | i of an alive cat.In other words, it is for certain that the friend Schrodinger will say that he found a dead or alivecat, as the case may be, before Wigner asked him. This means in particular that in the referenceframe (so to speak) of Schrodinger the state vector, even before Wigner’s measurement, wasalready either | i or | i and not their linear combination, which is in gross contradiction to thequantum mechanical rule (2.3) verified experimentally to a great accuracy.This is not to say that Schrodinger’s position is less reasonable since quantum mechanicsassumes him (in the reference frame of Wigner) to occupy the linear combination | Ψ i whichimplies in a clear sense as Wigner puts it: ”that my friend was in a state of suspended animationll rights reserved to Badis Ydri before he answered my question” [17]. In other words, third-person observes (with respect towhom there is no collapse) really act as if they were philosophical zombies.This experiment shows also among other things the non-tenability of objective collapsemodels (every measurement will produce a collapse for everybody) as opposed to the subjective-collapse models such as the Copenhagen interpretation (in which every observer is assigned acollapse in her own measurement only).In summary, quantum mechanics enjoys four properties, which if taken at face value, makesthe corresponding interpretation fall an easy prey to solipsism (or subjective idealism). Theseare:1. Quantum mechanics is naturally a dualistic theory in which the dual relation betweenobserver and observed is lifted to a dual relation between consciousness and matter con-sidered as two different aspects of a more fundamental and more neutral substance.2. Quantum mechanics is strongly perspectival in character, i.e. the role of the observer isirreducible and objective reality is nothing less or more than an omni-perspective whichis a total coherent sum of all the perspectives of all the observers existing in this world.3. The world is not causally closed (taking into account the physical alone) if observers andconsciousness can not be eliminated. Indeed, the collapse of the wave function requiresthe action of a conscious observer. In other words, consciousness acts as a kind of ”darkenergy” with causal influence on matter.4. The (classical pointer) states of the physical system (or the world) exist only potentiallyand their existence becomes actualized or realized only when a measurement is performedon the physical system (or the world) in accordance with Bell’s theorem. In other words,a transition from potential to actual existence occurs only when the wave function col-lapses. The collapse of the wave function acts therefore as a completely independent ”fifthforce” in nature connecting the mental to the physical similar to the psychophysical forceproducing qualia which connects the physical to the mental.As it turns out, most of the interpretations of quantum mechanics and most of the philosophyof (quantum) physics are in fact an attempt to explain away the above four straightforwardproperties of quantum mechanics. The only known exception to this rule is the he Wigner-vonNeumann interpretation (also called ”the mind causes collapse” interpretation) which can bedefined precisely by the above four properties.These properties amount effectively to a solipsism which is a reality in which only themind of the knowing subject or the observer is objectively real and everything else is only anappearance, i.e. an idea in the mind of the observer with no thing-in-itself behind it.However, the form of solipsism suggested by property 4 is much weaker than this since itstates that the classical states which are actualized by the act of observation are actually actu-alized by an objectively real psychophysical action of a conscious observer (since measurementll rights reserved to Badis Ydri requires a conscious observer in this scheme) and hence the action (not only the consciousness)of the observer is also real within this interpretation which should extend to the entirety of thepsychophysical world. The Wigner-von Neumann interpretation of quantum mechanics was presented in this essay.It is argued that this interpretation, if taken as an effective theory, will involve four interwovenelements which are: 1) quantum dualism, 2) perspectivism as an extended complementarityprinciple, 3) psychophysical causal closure and 4) solipsism. But as a fundamental theory theWigner-von Neumann interpretation depicts a reality of neutral monism which is complemen-tary to the physicalism of the many-worlds.Indeed, within this scheme we have from one hand the fact that in the single-world theinteractions of the ontologically distinct degrees of freedom associated with the consciousness ofthe classical observer with the physical degrees of freedom of the quantum physical system giverise to the collapse of the wave function whereas from the hand we have the complementarityrelation between the Copenhagen interpretation and the many-worlds formalism. This meansin particular that the degrees of freedom associated with the consciousness of the first-personobserver in the single-world are dual to the purely physical degrees of freedom associated withthe many-worlds. As a consequence the quantum dualism employed by the first-person observersis a complementary description to the physicalism employed by the third-person observers.The property of solipsism, which is seen as dual to the property of many-worlds, can begiven a much weaker import by appealing to the many-minds interpretation and the underlyingneutral monism.Finally, we briefly comment on two intimately related topics.
By analogy with the simulation hypothesis [34] the first-person observers of the Copenhageninterpretation (who see the collapse of the wave function) play the role of the simulated beingspopulating the simulation whereas the third-person observers of the many-worlds formalism(who are wholly unitary) play the role of the biological beings who are running the simulation.Therefore, the simulated conscious first-person observers are like players in a giant virtualreality game and what they observe in the simulation is the rendering of the content of thesimulated environment which appears to them as the the collapse of the wave function whenreality is finally experienced.For quantum systems the simulated reality is not computed until the observer or the playerseeks the experience or observation. This is simply due to the high cost of the calculations andto the limited resources available to the simulator. This is then the statement that the electronis not out there until observed (Bell’s theorem).ll rights reserved to Badis Ydri But in classical systems the numerical calculation is low cost and therefore the computerperforms the calculation well before the observation or rendering time. So the moon is reallyout there even when we are not looking at it.The above definition of physical reality as the connection between the rendering-of-the-simulated-environment to the player and the collapse-of-the-wave-function seen by the observeris based implicitly on the assumption of finite computation resources and requirement of lowcomputational complexity [35].Furthermore, if we are living in a simulated reality it is easy to imagine that the beingsrunning the simulation has also computed the other parallel branches of the world. In fact thisis only natural from the simulators point of view. These beings are the third-person observersof the many-worlds formalism who observe directly coherent linear superpositions and thus thecorresponding global structure of reality not only the local one associated with Copenhagen.The simulation hypothesis provides therefore a vivid metaphor or visualization of the laws ofquantum mechanics. But it can also be considered as a genuine metaphysical theory in its ownright. In other words, we are indeed likely to be among the simulated beings rather than amongthe biological ones. This provides therefore a powerful starting point for a new interpretationof quantum mechanics.
The fact that there are two types of change in time within the Copenhagen and Wigner-von Neumann interpretations means in particular that there are two fundamental measures oftime which are not necessarily the same. The unitary evolution of the Schrodinger equationcorresponds precisely to the objective physical time. Whereas the collapse of the wave functionin the measurement process (as seen by first-person observers such as Schrodinger) correspondsto the subjective psychological time experienced by consciousness. It is the psychological timethat has an arrow which is perspectival in character. These two times are not necessarilyidentical and they are expected to be unified (resulting in truely quantum time) within theframework of a new psychophysical theory of quantum mechanics (quantum gravity) in which afine-grained unitary time evolution must replace the gross-grained Schrodinger time evolutionwhich terminates dynamically (leaving the collapse in its place) each time a measurement isperformed by a conscious observer.The existence of two measures of time: i) the objective physical time (unitarity) and ii) thesubjective psychological time (consciousness and collapse of the wave function) could be at theroot cause of the problem of temporal non-locality in neuroscience discovered in experimentsby Libet in 1983 [33]. It was discovered in these experiments that the readiness potential inthe brain (which precedes voluntary movement) begins to rise in the brain before the consciousdecision to move. By thinking about the conscious decision to move as marking the subjectivepsychological time associated with the collapse of the wave function whereas thinking aboutthe rising of the readiness potential as marking the objective physical time we can see that thediscrepancy found by Libet can be interpreted as a slight failure of synchronization betweenll rights reserved to Badis Ydri the physical and the mental, i.e. the psychophysical parallelism is not exact. This is usuallyinterpreted as indicating a compatibilistic free will. References [1] J. von Neumann, “Mathematical Foundations of Quantum Mechanics,” First edition(1955), Princeton University Press, translated from the 1932 German original by R. T.Beyer.[2] Eugene P. Wigner, “Symmetries and Reflections,” Indiana University Press, Bloomington,1967.[3] D. A. Edwards, “The mathematical foundations of quantum mechanics,” Synthese (1979)42: 1. https://doi.org/10.1007/BF00413704.[4] G. Birkhoff, J. von Neumann, ”The Logic of Quantum Mechanics,” Annals of Mathemat-ics, 2nd Ser. 37 (4): 823843. JSTOR 1968621.[5] D. Chalmers, “The hard problem of consciousness,” D. Chalmers, “Naturalistic dualism,”In M. Velmans, S. Schneider, The blackwell companion to consciousness, Blackwell Pub-lishers Ltd, 2007. See also his book ”The character of consciousness”, Oxford UniversityPress (2010).[6] N. Bohr, “Essays 1958-62 on Atomic Physics and Human Knowledge,” Wiley, 1963.N. Bohr, ”Discussions with Einstein on Epistemological Problems in Atomic Physics”.From Albert Einstein: Philosopher-Scientist (1949), publ. Cambridge University Press,1949. Niels Bohr’s report of conversations with Einstein.[7] D. Albert, B. Lower, “Interpreting the Many Worlds Interpretation,” Synthese, 77, pp.195213, 1988.[8] Nietzsche, Friedrich Wilhelm, Walter Arnold Kaufmann, and R.J. Hollingdale. The Willto Power. New York: Vintage Books, 1964. 481, p. 267. Friedrich Wilhelm Nietzsche andWalter Arnold Kaufmann. The Gay Science; With a Prelude in Rhymes and an Appendixof Songs. New York: Random House, 1974. Section 374, p. 336.) Friedrich Nietzsche, Onthe Genealogy of Morality: A Polemic. trans. Maudemarie Clarke and Alan J. Swenswen.Indianapolis: Hackett Publishing, 1998.)[9] Anderson, R. Lanier, Truth and Objectivity in Perspectivism, Synthese (1998) 115:1-32.[10] M. Kulstad and L. Carlin, Laurence, ”Leibniz’s Philosophy of Mind”, The Stanford Ency-clopedia of Philosophy (Winter 2013 Edition), Edward N. Zalta (ed.).[11] J. S. Bell, “On the Einstein-Podolsky-Rosen paradox,” Physics , 195 (1964).ll rights reserved to Badis Ydri [12] J. S. Bell, “On the Problem of Hidden Variables in Quantum Mechanics,” Rev. Mod. Phys. , 447 (1966).[13] Rene Descartes, “Meditationes de prima philosophia, 2nd edition, 1642.[14] Benedict de Spinoza. “Ethica, 1677. A translation called Ethics by Andrew Boyle, revisedby G. H. R. Parkinson, is published by Everymans Library, 1989, 1992.[15] J. Kim, “Physicalism or something near enough,” Princeton University Press (2005).[16] J.D. Trimmer, ”The Present Situation in Quantum Mechanics: A Translation ofSchrodinger’s ’Cat Paradox’ Paper,” Proceedings of the American Philosophical Society124:5 (Oct. 10, 1980), 323-338.[17] E. Wigner, ”Remarks on the Mind Body Question,” In: Mehra J. (eds) PhilosophicalReflections and Syntheses. The Collected Works of Eugene Paul Wigner (Part B Historical,Philosophical, and Soci o-Political Papers), vol B/6. Springer, Berlin, Heidelberg.[18] H. D. Zeh, “On the Interpretation of Measurement in Quantum Theory,” Foundation ofPhysics, vol. 1, pp. 69-76, (1970).[19] H. Everett, “Relative State Formulation of Quantum Mechanics,” Reviews of ModernPhysics. 29: 454462, 1957.[20] H. Everett, J.A. Wheeler, B.S DeWitt, L.N. Cooper, D. Van Vechten, N. Graham, ”TheMany-Worlds Interpretation of Quantum Mechanics,” B. DeWitt, N. Graham, (editors).Princeton Series in Physics (1973). Princeton, NJ: Princeton University Press. p. v. ISBN0-691-08131-X.[21] M. Tegmark, “The Interpretation of quantum mechanics: Many worlds or many words?,”Fortsch. Phys. , 855-862 (1998) [arXiv:quant-ph/9709032 [quant-ph]].[22] L. Susskind, “Copenhagen vs Everett, Teleportation, and ER=EPR,” Fortsch. Phys. ,no. 6-7, 551 (2016). [arXiv:1604.02589 [hep-th]]. L. Susskind, “ER=EPR, GHZ, and theconsistency of quantum measurements,” Fortsch. Phys. , 72 (2016). [arXiv:1412.8483[hep-th]].[23] W. Heisenberg, “Is a deterministic completion of quantum mechanics possible?,” Trans-lation by E. Crull and G. Bacciagaluppi, https://halshs.archives-ouvertes.fr/halshs-00996315.[24] A.M. Gleason, ”Measures on the closed subspaces of a Hilbert space,” Journal of Mathe-matics and Mechanics, 6: 885893 (1957).[25] S. Kochen, E.P. Specker, ”The problem of hidden variables in quantum mechanics”, Journalof Mathematics and Mechanics 17 (1967), no. 1, 59-87, Reprinted in [Spe90, pp. 235-263].ll rights reserved to Badis Ydri [26] A. Einstein, B. Podolsky, N. Rosen, ”Can quantum-mechanical description of physicalreality be considered complete?”, Physical Review 47 (1935),777-780, Reprinted in [WZ83,pages. 138-141].[27] B. Misra and E. C. G. Sudarshan, “The Zeno’s Paradox in Quantum Theory,” J. Math.Phys.18