Physics causal completeness

Cassirer summarized his discussion of the history and current understanding of probability (and hence irreversibility) statements in the comment From all this we can conclude that causality and probability , order according to law and accident , not only can but must exist side by side when we want to determine an event as completely as possible. In classical physics causality refers essentially to the knowledge of the course of the event, and probability to the knowledge of its initial conditions. From the two combined there arise the theorems of statistical mechanics (1956, 104). 

The failure of Pure Mechanism on account of the existence of irreducibly macroscopic qualities need not bear directly on the completeness of physics. It may be possible, after all, that the mechanistic laws governing the interactions of microscopic particles are causally complete, and the macroscopic qualities consequently causally inert with respect to the behavior of systems of microscopic particles. Broad seems to have been aware of this possibility, for given the assumption that sensible objects really do have the irreducibly different sensible qualities they appear to have,7... 

Note, however, that Kim s property identities are in themselves insufficient to rule out downward causation. What is required in addition is the causal completeness of physics with respect to systems within which the physical properties that realize these second-order properties are instantiated. 

Kim then appeals to a principle he calls Closure (what we earlier called the causal completeness of physics ) ... 

Turing AM (1950) Computing machinery and intelligence. Mind 59(236) 433-460 Vicente A (2006) On the causal completeness of physics. Int Stud Philos Sci 20(2) 149-171 Woolley R, Sutcliffe B (1977) Molecular structure and the Bom-Oppenheimer approximation. Chem Phys Lett 45 393-398... 

The drive towards standalone explanations - cohesive explanations consisting of a complete set of difference-makers (picked out by the kairetic procedure) that causally entail the production of the explanatory target - is to provide depth to our scientific understanding of nature. Strevens favoured sense of depth resides in models that account for a phenomenon by picking out a causal structure that is at the same time very abstract and very physical causal models that pick out facts about causal influence at the fundamental physical level and are very abstract or general (ibid, p. 137). 

Contrary to what appears at a first sight, the integral relations in Eqs. (9) and (10) are not based on causality. However, they can be related to another principle [39]. This approach of expressing a general principle by mathematical formulas can be traced to von Neumann [242] and leads in the present instance to an equation of restriction, to be derived below. According to von Neumann complete description of physical systems must contain ... 

Health is a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity (WHO, 1948). This implies that the human health effects which are relevant indoors include both adverse effects and changes of well-being associated with exposures to environmental factors. Therefore, the diagnosis of an environmental health effect, includes both identification of a human health problem and an exposure, that is, identification of causality. 

The elucidation of the dependence of various chemical and physical properties of substances on molecular structure can be considered as one of the main goals of theoretical chemistry. Although an immense knowledge has accumulated in this field, a fairly limited number of direct, causal and quantitative (or at least semiquantitative) structure-property relations have been discovered so far. The main reason for this is the enormous complexity of the quantum-chemical calculations, by means of which the contemporary theoretical chemists try to describe and predict the behaviour of molecules. During such calculations the insight into the actual connection between the input (e.g. molecular structure) and output (e.g. certain molecular properties) is usually completely lost. 

More severe conceptual problems arise in relativistic quantum mechanics, where the analogous scheme leads to completely non-physical results. In the process leading to formal localization and to complete uncertainty of momentum information, the information on the reference frame itself is lost, consequently, one can no longer determine what events can be regarded as simultaneous. Consequently, a conventional, classically interpreted localization approach within a relativistic quantum mechanical framework leads to nonsensical results. For example, if one assumes that localization is possible [6] and, as an initial condition, a relativistic particle is forced to be fully localized at some time t = 0, then the complete uncertainty of the reference frame implies that the same particle is already spread over the whole space at any later time t > 0. Within such a model causality is lost, and the relativistic model itself becomes self-contradictory [6],... 

Papineau s version of the completeness of physics concerns the science of physics, while Kim s version concerns the causal relations which are its subject matter. The relation comes via Papineau s contention that the science of physics aims at completeness, in the sense that the causal processes it describes—or in the ideal limit of physical inquiry would describe—are closed with respect to the non-physical there are no causal factors which are not described by physics, or for whose description physics defers to another science. In this respect, physics is, he argues, quite different from, for instance, meteorology, chemistry, biology, and psychology, all of which admit external causal factors. 

Now notice here that Kim refers to events and not properties in his statement of strong closure. If Kim were really just talking about events here, then strong closure would be completely uncontroversial and rmproblematic for any materialist. Nonreductive materialists could hold on to a Davidsonian anomalous monism, and hold that all causes of physical events are themselves physical events. This would still leave open the possibility that these physical events could have physically irreducible properties that are sometimes causally potent. 

Notice that by reformulating Exclusion and Exclsuion in terms of sufficiency in an effectively closed model, Weslake is filling out exactly what he means by a complete causal explanation or a complete causal model specifying an explanation for an event . By complete , he seems to mean that there exists a sufficient actual cause within an effectively closed model. Because there is a sufficient actual cause framed only in physical variables, our explanation in terms of physical variable will be complete,... 

Once the causal analysis is completed, each of the causes that cannot be shown to be physically impossible must be checked to determine whether they are... 

So, here s the exclusion argument itself Suppose that some M-instantiation causes an TVf-instantiation. By supervenience, we know that the -instantiation has a physical supervenience base, But P -instantiation is nomologicaUy sufficient for AP-instantiation. It therefore appears that Af and P each have a claim to being responsible for the instantiation of Af on this occasion, and the two claims appear to be in tension with each other. The only plausible way to resolve this tension is to conclude that the Af-instantiation causes the AP-instantiation by causing a P-instantiation. But, again by supervenience, Afhas a supervenience base, P. By the causal closure of the physical, the P-instantiation must have a complete physical cause — presumably, the P-instantiation. But now P and M are in direct competition for being the cause of the P-instantiation. ... 

The first two claims characterize a physicalist worldview, or what I call physicalism. Condition (r) expresses the physicalist idea that all God needed to do to make the universe is to distribute the fundamental physical properties in space and time and make the laws of fundamental physics. All facts about macroscopic objects, their colors and behaviors, and facts about people, their thoughts and experiences, and truths about causation and the special sciences, and so on are metaphysically entailed by the fundamental physical facts and laws. Condition (2) says that the physical laws are closed and complete in the sense that, given the complete fundamental physical state at t and the laws, whether or not E occurs at t, or its chance of occurring, is completely determined. 1 assume that whatever causation is, condition (2) implies the casual completeness of physics in that E t ) s physical causes at t are sufficient to determine its occurrence (or the chances of its occurrence). Condition (2) is a consequence of (r), and it is possible to derive (r) from (2) and some other plausible premises, but I separate them since nomological and causal closure will figure importantly in our discussion. ... 

Insofar as Hendry s theory of emergence focuses on entities, it is at odds not only with reductionism, but also with the causal closure or completeness of physics - the thesis that all physical events are determined (or have their chances determined) entirely by prior physical events according to physical laws (Papineau 1990, p. 67). This is because on Hendry s view, molecules are capable of downward causation. So if the theory of emergence advocated by Hendry is true, the set of physical causes must be supplemented with sui generis chemical causes - molecules exerting downward causation on their parts. 

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