Massimo Pauri is a professor of theoretical physics with a great interest in the philosophy of science. He has written on understanding the quantum, on determinism and indeterminism,
on the idea of "causal closure" with its implicit reductionism, and on the impact of these physical ideas on the mind-body problem and the problem of free will. In his 2011 paper on the "Evolutionary Role of the Quantum," Pauri writes:
I believe that the great majority of people belonging to the science community at large, mainly influenced by the complexity and operational efficacy of the formalism of QT, may not be fully aware of the philosophical radicality of the historical event represented by Planck’s discovery. Namely the physical fact that the action is made up of indivisible units (quantum), measured by the Planck constant h. It is important to realize in the first place that the action is a theoretical entity (of the classical description) which is neither a spatial nor a temporal quantity, nor is it a property of things, yet it encodes both spatiotemporal and dynamic components. In other words, what turned out to be atomized are processes instead of things: the true atom (‘indivisible’) of contemporary physics is then the quantum of action. Thus we have a dramatic shift from the naïve or spatio-temporal atomism (atoms as simple and indivisible spatial entities) to action-atomism (atoms as indivisible elementary processes). The consequence is that it is not the small physical size (i.e. a spatiotemporal characterization) that defines the quantum level, but something more subtle concerning processes in terms of time and energy differences. Let me stress the main immediate outcomes of this revolution. Let us consider a whole as an aggregate of putative parts and an inner dynamical process of interactions among such putative parts. In traditional classical terms, this process would be conceived as a variety of exchanges of energy E at some intervals of time t, as well as transfers of linear momentum P along some intervals of space x. The expression A = ΔEt − ΔPx = Δμxμ is just the relativistic invariant expression of the action phase, and the putative parts of the whole are then thought of as exchanging action among themselves. Now, the atomization of the action entails that there cannot exist real processes corresponding to exchanges of action smaller than the Planck constant. Even more, the elementary quantum act (corresponding to a single quantum of action exchanged between two putative parts of a whole) is simple: literally it has no spatial extension nor duration. More generally, all the genuine quantum processes, in a deep sense do not belong in the extensional space and time (I mean in the sense of the Raum and clock time of our real macroscopic experience), so that they cannot be represented as taking place in spatial extension during lapses of time. Since the action is, classically, a continuous functional of the physical system’s configuration, were a continuous spatiotemporal description of the interacting parts conceivable, there would be real intermediate states, and one would be able to reconstruct processes corresponding to actions of arbitrary measure. In conclusion, stricto sensu: (i) the parts cannot be described in any local way as entities in the extension (and time) of our experience so that they simultaneously lose their traditional individuality. In fact, the parts can no longer be conceived as distinguishable individuals, i.e., they are no longer objects in the ordinary sense of perceivable things. If the parts were objects, the action could not be atomized! Furthermore (ii) any genuine quantum phenomenon is an undivided whole and cannot be broken up into physically well-defined steps; (iii) ‘Quantum ontology is one of abstract entities, though not of mental ones’. Only the revelations or measurements of the effects of quantum processes are phenomena in the Raum and time of our experience. Revelations, however, are not genuine quantum processes. They are highly complicated semi-macroscopic processes magnifying quantum events to the classical level by producing irreversible traces in ordinary Raum and time so that they are indeed characterized by quantitative measures of extension and duration and are perceived as actual occurrences. However, they fail to be describable by quantum theory...Pauri talks about the problem of measurement and ‘measurement-like’ processes without any observer (collapse of the wave function before observers existed, for example).
Corresponding to the measurement M, the state vector ψ ‘jumps’ and coincides by definition with the ‘eigenvector’ of the observable P corresponding to a definite ‘eigenvalue’ or property ‘p’ of the system S. Note that M (also called reduction of the state vector or wave function collapse) is a pragmatic ad hoc operation (Postulate of the ‘Wave Packet Reduction’: WPR) which instantaneously redefines the state as represented by the State Vector ψ, which embodies the new information about the system. Here is where a main issue lies, however. For, if taken outside the formal set of postulates of QT, it is not clear in the first place what the difference is between a ‘measurement’ belonging to the list of postulates or to the set of highly idealized laboratory man-made operations, on the one hand, and the ‘measurement-like’ processes that are going on, more or less all the time, more or less everywhere [Bell, "Against Measurement"], on the other hand. In the latter case, the state vector ψ (or the wave function) should be better interpreted as representing something physically real, and the variation of the state vector under such generalized ‘measurement’ should be intended as describing a real physical process as ruled by a second kind of evolution law (called R by Penrose). R would enter into play when different macroscopic effects are triggered by different microscopic situations, and — in the current status of the theory — is supposed to be described (in principle and only elliptically) in a pure phenomenological way by a non-linear and stochastic process (still reduction of the state vector or wave function collapse).In section 4, Pauri summarizes his conclusions:
(1) The ontological elusiveness or, rather, inconsistency of spatial extensionality resulting from the classical debate; also, the very ontological vagueness of the extensionality of spacetime in GTR. (2) The Kantian legacy within the phenomenological tradition, concerning the epistemic primacy and unavoidability of the pre-phenomenal extensional continuum. (3) The relevance of perception of distinct material objects in the extensional Raum of our experience, and its role as a precondition for subjectivity and self-consciousness in particular.(4) The suggestions according to which the spacetime of the classical scientific image could be an emergent reality from a quantum substrate. (5) The fact that micro entities lack object-like properties and that genuine quantum processes do not belong to the spatial extension of the Raum, except for the results of specific ‘measurement procedures’ which take place according to large scale irreversible amplifications. (6) The intrinsic non-locality of Nature at the quantum level independently of the specific formalism of the theory; a property that, extending at macroscopic distances, gives a further impressive blow against the ontological robustness of the extensionality of space: non-local quantum correlations somehow seem to emerge from outside space and time. (7) The nature of the X-mysteries and the conflicting views about their clarification. (8) The fact that linearity of quantum evolution is a very well confirmed phenomenon only at the quantum level.
Time, Physics, and FreedomIn his 2007 essay, "Time, Physics, and Freedom: at the Roots of Contemporary Nihilism," Pauri discusses issues of determinism and indeterminism, the idea of "causal closure" with its implicit reductionism, and the impact of these physical ideas on the mind-body problem and the problem of free will. His paradigm case of determinism is found in the work of mathematical physicist Steven Weinberg, whose view of Nature he describes as "Deterministic Grand Reduction." He says, "I believe that, when properly scrutinized, Weinberg’s view turns out to be a strong, but irrational metaphysical thesis, according to which the facts of the past, in conjunction with the laws of nature, entail every truth about the present and the future." This view is that of most compatibilists and determinists on the problem of free will (e.g., see John Martin Fischer). Pauri's work focuses on "three main issues: namely a crucial logical junction that I would like to call the freedom of meaning, the issue of determinism and free will, and the philosophy of time in conjunction with the mind-body problem." "Two-stage models of free will" break the causal chain of any hypothetetical determinism coming from the "fixed past." They use quantum-level indeterminism in the first stage, which generates alternative possibilities for action. These are evaluated in the second stage, which is a "willful" and "adequately" determined process that considers motives, reasons, and desires to choose between the "freely" generated alternatives of the first stage.
Pauri examines the role of time in the traditional question of freedom and free will.
Briefly, if we are not able to freely believe and freely think in a meaningful way, we are not even able to freely will and freely act in the world, and vice-versa. The conceptions of time also bear upon the same problems. In particular, as is evident from history of philosophy – Kant’s thought especially – the issue of freedom and free will is strictly related to the way in which subjectivity is thought to stay in time. Thus, my analysis will be jointly directed to the analytic view expounded in the so-called A and B-theories of time. I will then discuss the consequences of the implicit assumption that the metaphysics of time is dictated by the role played by physical time within the theoretical structure of physics, in particular by a literal interpretation and reification of the spatio-temporal models of the relativity theory. A further instantiation of the same logical junction concerning meaning and freedom of choice is provided by the current reductionist and ideological interpretation of strict Darwinism.Pauri argues for the ability of a free agent to initiate new causal chains (e.g., in the first stage of a two-stage model) and then describes a "quasi macrodeterminism.":
The so called causal closure of physics is only a restriction to the reduced, idealized ontology of a broader general causality of the world which must thereby be admitted. The causal closure of physics is only valid under the condition that the theorizing subject (the agent subject) does not intervene in the dynamic play of the game once the initial conditions are settled. Correspondingly, physical time, related to physical causality, is just a reduction of what I call real time of the world, which is related to the general causality of the world. In the open world a free agent can initiate an emergent causal chain (emergent with respect to the reduced physical causality), that subsequently exploits the quasi macrodeterminism allowed by the physical description under specified conditions.4Note that the two-stage model of free will is a temporal sequence in which a free agent can initiate an emergent causal chain, as Pauri says. It is similar to the two-step process of Darwinian evolution which initiates new biological species, as first pointed out by William James. The two-stage model also maps onto the BVSR (Blind Variation, Selective Retention) theory of human creativity as popularized in psychology by Donald Campbell and
Dean Keith Simonton. Pauri is not comfortable with the conjunction of Weinberg's Deterministic Grand Reductionism (DGR) and a Darwinian evolution that extrapolates from "laboratory Darwinism" to the cosmological level (EDM). He says:
The Darwinian theoretical model is based on a fundamental connection between the essentially random character of mutations and the process of natural selection due to adaptation to the environment. ... according to [laboratory Darwinism], single mutations are probabilistic observable events (note that they only resemble pure quantum processes: there are no “quantum events” in spacetime !), the underlying philosophical backdrop of EDM is the same as the DGR view of Nature (“chance and necessity”). Let me add that the “chance” referred to in EDM is a sort of metaphysical, negatively defined, entity, well distinct from the “chance” embedded in formal probabilistic theories fitting scientific descriptions.We hope that Pauri might like our information philosophy view of evolution, from the original particles of radiation and matter, through planets, stars, and galaxies, to life and mind.