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Mauro Dorato (md2499@mclink.it)
& Francesco Orilia (orilia@unimc.it) Università di Roma3 & Università di Macerata  We shall propose a picture of issues traditionally regarded as philosophical by relying on the contention that there is no clear-cut borderline between philosophical and scientific methods and problems (at least if by "philosophy" we mean "analytic philosophy").It is widely assumed that common sense somehow relies on theories, such as naive physics or folk psychology, which can be formally reconstructed, e.g., for the purposes of artificial intelligence. Traditional ontological investigation in the analytic style (analytic ontology) can then be viewed as an attempt to uncover the most general aspects of the theory of the world implicit in common sense and natural language (folk ontology). Such investigations can be accomplished by testing competing theories against collections of data, similarly to what is done in empirical sciences such as physics. The data considered by the folk ontologist are linguistic in nature, as they are based on what a "typical" speaker would be disposed to assert in certain circumstances. For example, someone asserting both "John believes that Venus is a planet" and "the morning star is Venus" would not necessarily be disposed to assert "John believes that the morning star is a planet". However, after asserting "event e caused event e'", one should be prepared to assert "e occurred before e'". In order to evaluate a collection of data of this kind, the ontologist typically relies on her arm-chair intuitions, which, however, could in principle be tested by relying on statistically significant samples of normal speakers. We claim that the central core of folk ontology is a conception of reality - call it PPR - as made up of distinct particulars, endowed with properties and connected by relations in a mind-independent fashion. We begin by briefly mentioning the main competing analytical reconstructions of PPR, from the view according to which objects are bundles of individual tropes, to the altenative view according to which objects are bare substrates exemplifying universals (yet other views adopt an ontology of events or states). We then go on to discuss the central issue of our paper, which is whether there are versions of PPR that are either (A) somehow presupposed by contemporary physics (quantum mechanics and the theory of relativity in particular), or (B) at least compatible with it. Although - at least since Galileo - we are used to clashes between naive physics and scientific physics, conflicts between the latter and folk-ontology are hard to digest, for they may lead to the rejection of theses traditionally regarded as a-priori conceptual truths. Nevertheless, in the light of relativity theory and quantum mechanics, some such theses may have to be abandoned. For instance, given that the special theory of relativity (STR) denies the existence of a privileged inertial frame - which Newton still admitted - the reidentification across time of a particle or of the spatial parts of a substance is arbitrary, because it depends on the velocity of the observer. By applying Quine's slogan "no entity without identity", the very notion of a substance might have to be relinquished, simply as a consequence of STR. Moreover, due to the relativity of simultaneity - the fact that two spatially separated entities may be simultaneous for an inertial observer, but temporally successive for another inertial observer - two spatially separated substances cannot be "co-present" in any objective way. It has then be argued that if the main difference between substances and events is the fact that only the latter (but not the former) have temporal parts, and if we, qua persons or substances, bear a relation of coexistence to, say, Tony Blair but not to Winston Churchill, there might be no objective way to implement an ontology of substances in a relativistic spacetime. Despite this difficulty with relativity, we argue that it is especially from the standpoint of quantum field theory that problems for A and B above arise. According to a standard interpretation of such a theory, in fact, the basic constituents of reality are fields or, at most, literally indistinguishable "particles" (field quanta). Moreover, presupposing some form of objective, non-epistemic quantum indeterminacy, the status of the properties of quanta is unclear and controversial to say the least. Accordingly, neither (A), nor (B) can be taken for granted. With respect to this issue, in particular we shall examine whether quantum individuals - which lack, as Teller claims, primitive thisness (heacceitas) - can be regarded as compatible with PPR. The methodological standpoint that we presuppose in investigating the credentials of PPR vis à vis contemporary physics can be summarized by listing the following four theses: (T1) The survival value of natural language and common sense prima facie suggests that the best available reconstructions of folk theories are by and large true theories (Quine, Davidson and Castaneda). (T2) The predictive power and explanatory and technological success of science are best explained by the hypothesis that the currently accepted scientific theories are by and large true, and that the so-called theoretical terms of a mature science are genuinely referential. (T3) In case of conflict between a currently accepted scientific theory and a folk theory, folk realism should yield to scientific realism. (T4) If there are otherwise equally acceptable reconstructions of PPR, one should try to choose by assessing which one fits more harmoniously with the world-view proposed by contemporary physics. If both (A) and (B) were ultimately to be rejected, because of their incompatibility with physics, we would face an important choice. We could either deny (T3), by endorsing some form of scientific antirealism, or we might try to keep (T3) by lending support to some of the philosophical rivals of PPR. Perhaps, Kant's critic philosophy and descendants thereof, could be seen in this light. In fact, from a Kantian point of view, at most we can postulate a mind-independent reality, but this should be regarded as an indivisible whole, whose constituents and structure cannot be coherently grasped by our categories. In this perspective, properties and relations cannot be distinguished from mind-dependent concepts, given that the latter are at best intersubjective, but surely they are no objective ingredients of reality in the sense in which the properties and relations of PPR are. Of course, by opting for this alternative, it would be legitimate to ask in what sense we would still have a form of scientific realism. On the other hand, if either (B) or (A) are defensible, PPR would be a plausible empirical hypothesis, supported by (T1) or even by (T2), and thus preferable to rival accounts such as the Kantian one. |
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www.vc.unipmn.it/~sifa/sifa.htm |