Michael Esfeld

Physicalism and Ontological Holism

The claim of this paper is that we should envisage physicalism as an ontological holism. Our current basic physics, quantum theory, suggests that, ontologically speaking, we have to assume one global quantum state of the world; many of the properties that are often taken to be intrinsic properties of physical systems are in fact relations, which are determined by that global quantum state. The paper elaborates on this conception of physicalism as an ontological holism and considers issues such as supervenience, realization of higher-order properties by basic physical properties, and reduction.

The Mutual Enrichment of Quantum Holism and Holism in Philosophy of Mind

What is meant by holism in quantum physics and what is meant by holism in the philosophy of mind has a substantial common conceptual content. However, we cannot melt these two sorts of holism together in order to reach one comprehensive holism. So what is the significance of this common conceptual content? I propose a mutual enrichment of these two sorts of holism. In particular, the common conceptual content of quantum holism and holism in the philosophy of mind shows that holism in the philosophy of mind fits into a view of the world that bases itself on scientific realism [10.1]. Quantum holism can be used to cut off one aspect of the alleged link between holism, indeterminacy and eliminativism in the philosophy of mind [10.2]. Furthermore, quantum holism and holism in the philosophy of mind both support the same supervenience claim, namely global supervenience in contrast to local supervenience [10.3]. Finally, both quantum holism and holism in the philosophy of mind point at the same new sort of realism which overcomes the opposition between metaphysical realism and relativism or instrumentalism. In conclusion, we can therefore say that both these sorts of holism make a significant common contribution to a contemporary philosophical view of the world and ourselves [10.4].

The Basis for Holism in Quantum Physics

What does holism in the philosophy of quantum theory mean? On which features of quantum physics is it based? In this chapter, the latter question is tackled. To start with, I sketch out the new conceptual features of quantum theory that are pertinent to quantum holism [7.1]. I then take up the distinction between the principles of separability and local action. Quantum theory violates separability. Einstein’s argument for the incompleteness of quantum theory is reconstructed [7.2]. Going into Bell’s theorem and its philosophical implications, I point out that the discussion on Einstein’s objections to quantum theory can be comprehended along the lines of the Duhem-Quine thesis [7.3].

Cartesianism in Physics and Holism about Space Or Space-Time

To what extent does holism in the philosophy of today’s physics break with the Cartesian tradition in modern philosophy of nature? To prepare the ground for an answer to this question, I show in this chapter that Cartesian philosophy of physics admits of a sort of holism. I take up the interpretation according to which Descartes and Spinoza consider matter and the continuum of physical, three-dimensional Euclidean space to be the same thing [6.1, 6.2]. Based on this identification we reach a holism which can be called “holism about matter as holism about space”: the parts of matter are identical with the points or regions of space. All physical properties are properties of points or regions of space. What makes something a point or a region of space is relational properties or relations to other points or regions within the whole of space. If the physical things are the points or regions of space, then any physical property can only be instantiated if there are many material things (points or regions of space) which extend as far as the whole material realm (the whole space) [6.3]. A theory of motion and change can be included in holism about space [6.4]. Finally, I examine whether holism about space (or space-time) can be directly applied to today’s physics. It is suggestive to try this holism out on general relativity. There is a programme for a further development of general relativity that amounts to a concrete elaboration of this holism, namely the geometrodynamics of Wheeler. However, this programme failed. We do not have a physics at our disposal which is not committed to physical systems over and above space-time. Even if we lay stress on the fact that Descartes’ and Spinoza’s philosophy of physics admits of a sort of holism, we cannot avoid a revision of Cartesianism in today’s philosophy of nature [6.5].

Holism and the Relation between Mind and World

This chapter reconstructs the relation between beliefs and the world from within social holism and holism about beliefs. I proceed in three steps. The first step is to employ the conceptual tools of the outlined inferential semantics in order to explain the representational dimension of beliefs. I follow Brandom’s account [5.1]. The second step is to argue that the proposed theory of meaning in terms of social practices is about the way in which we gain epistemic access to a world that is independent of these practices. According to the conception of social holism in terms of I-thou relations, the assessment of normative attitudes as correct or incorrect is an open-ended process. Consequently, normative attitudes that are shared by all the members of a community can be incorrect, and having beliefs can result in commitments that outrun the commitments which the persons in question acknowledge. This account implies a sort of response-dependence of our concepts. But this is a response-dependence that encroaches neither upon the meaning nor upon the truth of our beliefs. It is a constraint only on the acquisition of concepts. The upshot is a pragmatic realism that is beyond the traditional opposition between metaphysical realism and relativism. This pragmatc realism is not committed to any idealistic consequences [5.2]. The third step is to meet the challenge that McDowell poses to an account of meaning in terms of social practices by showing how social practices are anchored in a physical environment. I argue that McDowell’s position opens up a comprehensive holism that includes the physical world. However, I maintain that the described social practices are sufficient to conceive a rational constraint of the world on our beliefs [5.3]. Finally, I show that the resulting philosophy of mind is parsimonious in its ontological commitments: it is opposed to reductionism, but compatible with materialism without, however, implying materialism [5.4].

From Social Holism to Holism about Beliefs

The problem of rule-following as set out by Kripke in his interpretation of Wittgenstein’s Philosophical Investigations is the main argument for social holism [3.1]. This chapter gives an account of how — and to what extent — social practices can determine meaning for our beliefs. This account builds a bridge between the natural and the normative. Meaning is determined in social practices on the basis of our biological equipment. Nonetheless, the description of meaning cannot be reduced to a naturalistic description [3.2]. However, this account is a satisfactory solution to the problem of rule-following only if it is combined with an inferential role semantics. The rule-following considerations thus lead to an argument that covers both social holism and holism about beliefs [3.3].

The Extension of Quantum Holism and the Philosophy of Mind

Is quantum holism limited to more or less the microphysical realm? Or does it touch upon all physical systems? The issue of the scope of quantum holism is linked with the measurement problem [9.1]. When it comes to this issue, we should take the philosophy of mind into account — and in particular the discussion on holism and a revision of Cartesianism in today’s philosophy of mind. All those interpretations that regard quantum holism as universal in the physical realm are committed to epistemic self-sufficiency of intentional states and a representational realism. Consequently, they are incompatible with the revision of Cartesianism that goes with the proposed social holism and holism about beliefs [9.2]. By contrast, if one countenances a transition to a level of macroscopic systems which are not touched by entanglement, one can still regard quantum physics as a universal physical theory. But one can accommodate a macroscopic realm with definite properties. This is a prerequisite for direct realism and externalism (including social holism) in the philosophy of mind. The moral of this chapter therefore is a plea for caution: The arguments for holism and a revision of Cartesianism in the philosophy of mind sharpen up the task for the interpretation of quantum theory, and they constitute a weighty reason against the option for universal quantum holism. There is hence not one comprehensive, substantial holism that includes both the philosophy of physics and the philosophy of mind and that leads to a revision of the Cartesian tradition in modern thought [9.3].

Holism as Revision of the Cartesian Tradition

In this chapter, I start considering the broader implications of holism about beliefs and social holism for the philosophy of mind. The outlined holism about beliefs and social holism amount to a revision of the Cartesian tradition in epistemology. Two features of this tradition are relevant in this context: (a) a representational semantics including a representational realism and (b) the thesis of internalism or epistemic self-sufficiency of belief states [4.1]. As regards (a), it is shown how the proposed holism paves the way for a direct realism in contrast to a representational realism [4.2]. As regards (b), it is examined to what extent the proposed holism implies externalism as an alternative to epistemic self-sufficiency of belief states. According to this holism, the content of belief states depends on the social and the physical environment. In particular, social holism is a social externalism. It can moreover accommodate externalism with respect to singular thoughts and a type of direct reference. However, as far as an externalism such as the one of Putnam in “The Meaning of ‘Meaning’” is concerned, I argue that there is a tension between social holism and this externalism. For, according to social holism, beliefs are individuated by social practices instead of features of the physical environment. Features of the physical environment of which the speakers may be ignorant can contribute to the individuation of their beliefs only on the basis of a stipulation of the community to that effect. Consequently, the relation between beliefs and the world has to be established from within these practices [4.3].

The Meaning of Quantum Holism

If one endorses quantum holism, one is committed to a minimal requirement for an ontological interpretation of quantum theory: a system has those properties at a given time of which its state is an eigenstate. If one accepts this minimal requirement, one has to acknowledge that entanglement extends as far as the whole of matter at the level of quantum systems. Entanglement is distinct from interactions [8.1]. My proposal for a characterization of quantum holism combines the suggestions which exist in the literature and which employ the notions of non-supervenience and non-separability [8.2]: a quantum system has some of the properties which belong to the family of properties that make something a quantum system in the last resort only taken together with all other quantum systems. Consequently, the whole of matter is one holistic system at the quantum level. This proposal can leave open whether or not quantum systems are individuals; the issue of quantum holism thus is distinct from the issue of individuals [8.3]. Finally, I contrast this holism with the holism that can be built upon general relativity and that fits into a Cartesian philosophy of physics [8.4].

Arguments for Holism about Beliefs

Beginning with Quine’s “Two Dogmas of Empiricism”, the main arguments for holism about beliefs are considered. Three forms of this holism are distinguished: holism about (a) confirmation, (b) justification, and (c) meaning, i.e., semantic holism. It is suggested that (a) is best construed along the lines of the second type of the general conception of holism set out in the first chapter; (b) and (c), by contrast, can be construed along the lines of both types of this conception. I shall not be concerned with (b). As regards (a), I endorse Quine’s confirmation holism in “Two Dogmas”. However, I do not approve of Quine’s step to (c), because it presupposes verificationism [2.1]. I then go into the argument for semantic holism that bases itself on the conditions for the interpretation of persons. This argument on its own is neither necessary nor sufficient to establish semantic holism [2.2]. Therefore, the focus of this chapter is on the direct argument for semantic holism, namely inferential role semantics. The tasks for such a semantics are set out. Furthermore, the major objection against such a semantics is considered, i.e., that it does not allow for shared beliefs [2.3]. The strategy to counter this objection pursued here is to conceive inferential role as role in a social, linguistic community. In elaborating on this strategy, I base myself on Brandom’s “Making It Explicit” and follow Brandom in grounding an inferential role semantics on a normative pragmatics. According to this pragmatics, “meaning” is a normative notion; nonetheless, a descriptive theory of meaning is possible: In ascribing beliefs to a person, one describes the commitments that the person in question undertakes [2.4].