Modern Physics, Determinism and Free‑Will

If an observer observes an event, or any information recorded in a book, or on videotape, or in some other way for the first time, this is a completely unforeseen and random event for this observer, although it is predetermined.

2020

Concept of determinism has had many transformations throughout the history of physics, and it has been so influential in this field. However, with the growth of quantum physics, determinism became a scientific "dilemma" and has created many challenges in various contemporary sciences. If this concept is understood correctly, many misconceptions corresponding to it in natural sciences, especially physics can be removed. The aim of this paper is to investigate this concept analytically to solve the existing problems. To do this, first we consider the terminology of determinism including characteristic, necessary connection, and exact prediction. Then, William James definition of determinism, Laplacian determinism, Popper definition of determinism, causal determinism, logical determinism, epistemic determinism, metaphysical determinism, and theological determinism are introduced. After which, we pay attention to different kinds of determinism including global/local domain, co...

Knowledge and Values, ed. Adam Świeżyński, Wyd. UKSW, Warszawa 2011, pp. 73–94., 2011

The paper revisits the old controversy over causality and determinism and argues, in the first place, that non˗deterministic theories of modern science are largely irrelevant to the philosophical issue of the causality principle. As it seems to be the ‘moral’ of the uncertainty principle, the reason why a deterministic theory cannot be applied to the description of certain physical systems is that it is impossible to capture such properties of the system, which are required by a desired theory. These properties constitute what is called ‘the state’ of a system. However, the notion of a state of a system is relative: it depends on a particular theory which one would like to use to describe given kinds of phenomena. This implies that, even in the case where the desired state of a system is fundamentally impossible to be captured, neither ontological nor epistemological determinism may be excluded. Some following critical considerations are also offered with regard to the claim that uncertainty is “rooted in the things themselves”. The cradle of modern discussions about causality and determinism is, of course, quantum mechanics. Because, as it appears, a judgment on deterministic or non˗deterministic character of a theory can be made only after some interpretation of this theory has been given, the paper briefly reminds some chosen interpretations of quantum mechanics (Schrödinger's, probabilistic, statistical, Copenhagen, and the interpretation of quantum ensembles). Many of such interpretations, offered in the past, have now been rejected, and some gained more credibility than the others. Nonetheless, even the claim that indeterminism is irremovable from the description of the micro-world doesn't imply the rejection of the most general formula of the philosophical causality principle. There is no direct implication between theses of the epistemology of scientific knowledge and those of the ontology of the real world.

This paper argues for the following three theses: (1) There is a clear reason to prefer physical theories with deterministic dynamical equations: such theories are both maximally simple and maximally rich in information, since given an initial configuration of matter and the dynamical equations, the whole (past and future) evolution of the configuration of matter is fixed. (2) There is a clear way how to introduce probabilities in a deterministic physical theory, namely as answer to the question of what evolution of a specific system we can reasonably expect under ignorance of its exact initial conditions. This procedure works in the same manner for both classical and quantum physics. (3) There is no cogent reason to subscribe to an ontological commitment to the parameters that enter the (deterministic) dynamical equations of physics. These parameters are defined in terms of their function for the evolution of the configuration of matter, which is defined in terms of relative particle positions and their change. Granting an ontological status to them does not lead to a gain in explanation, but only to artificial problems. Against this background, I argue that there is no conflict between determinism in physics and free will (on whatever conception of free will), and, in general, point out the limits of science when it comes to the central metaphysical issues.

It is an often repeated claim in the literature that quantum mechanics is indeter-ministic and that it has put an end to the classical notion of causality. From the impossibility of determining the exact spatio-temporal trajectory of an atomic system, for instance, Heisenberg infers ‘the invalidity of the causal law’ in quantum mechanics [1]. What is tacitly assumed in such views is a chain of reasoning, which leads from determinism to causality. One form of determinism — predictive determinism — is the view that a sufficient knowledge of the laws of nature and appropriate boundary conditions will enable a superior intelligence to predict the future states of the physical world and to retrodict its past states with infinite precision. Laplace attributes this capacity to his famous demon: for the demon the physical world stretches out like the frames of a filmstrip. Each frame is caused by an earlier frame and in its turn causes a later frame. From the present frame the Laplacean demon is capable of predicting and retrodicting all other frames. Hence the demon identifies determinism and causality. ‘We ought to regard the present state of the universe as the effect of its antecedent state and as the cause of the state that is to follow’ [9]. Laplace assumes that these states are unique and can be determined with mathematical precision such that prediction and retrodiction become possible. The laws of physics are typically expressed in differential equations which describe the evolution of some physical parameter, P, as a function of time, t. As one state of a system, S1, evolves to another state, S2, where this temporal evolution is made precise by the employment of differential equations, it becomes easy to think of differential equations as precise mathematical representations of causal laws [10]. This is indeed how Einstein presented the matter: ‘The differential law is the only form which completely satisfies the modern physicist's demand for causality’ [2]. Although Russell [11] had argued that the ‘law of causality (…) is the product of a bygone age’ he nevertheless admitted causal laws in the form of functional relations and differential equations into physics.

Global Philisophy , 2024

We discuss the possibilities of determinism in reality, taking under consideration both quantum and classical physics. We present this firstly by questioning the supposed nature of quantum physics as non-deterministic, following the proposal of Penrose: the collapse of the wavefunction interpreted as particular measurements which seem to indicate certain contingency does not actually give the full picture of the reality of the former. In addition to what Penrose suggests, we consider this collapse as part of a bigger deterministic picture. Secondly, we analyse the distinction between this microphysical scenario and our macrophysical experience, in the light of determinism as well. We suggest that this experience can be understood as particular "measurements" similar to what happens in quantum mechanics. For instance, the image of a person with certain identity features is a highlight or particularization of all the possibilities the identity of this person experienced, experiences and will experience through time. The "collapse" is thus linked to individuation, not less real, but incomplete of reality. By linking the domain of quantum physics in a deterministic fashion to the phenomenological or macrophysical realm, we aim to show that a non-contingent character of reality is possible when accepting measurements or particular instances of things as forms of comprehension given by the physical world (thus not just mere subjective interventions). We argue that the complete picture (closer to the wavefunction) cannot give distinctive information (understanding this as differentiation of elements, such as particles in the microphysical domain and a certain colour in the macrophysical one).

2009

Abstract: In quantum gravity there is no notion of absolute time. Like all other quantities in the theory, the notion of time has to be introduced" relationally", by studying the behavior of some physical quantities in terms of others chosen as a" clock". We have recently introduced a consistent way of defining time relationally in general relativity. When quantum mechanics is formulated in terms of this new notion of time the resolution of the measurement problem can be implemented via decoherence without the usual pitfalls.

1976