Science and fundamental ontology

Ladyman and Ross (2007) present a version of naturalized metaphysics to weakly unify the special sciences by reference to fundamental physics.

‘Fundamental’ physics here means that part of physics that is implicitly tested, or could explicitly be confirmed, by every measurement that could be taken at any scale of reality and in any region of the universe. The unification is

‘weak’ because it is not reductionist. Fundamental physics constrains all special sciences (including the parts of physics that are not fundamental), but it doesn’t track information at the multiple scales necessary for capturing most of the‘real patterns’ (Dennett, 1991) that are the objects of study in chemistry, biology, geology, economics, and so on. Ontology is scale relative: all real patterns except those of fundamental physics are detectable at some scales but not at others. The same point applies to everyday phenomena tracked by reference to the parochial practical purposes of people, such as tables, hockey games, and capital cities. Mere patterns— stable but nonredundant relationships in data—are distinguished from ‘real’

patterns by appeal to mathematical information theory. A pattern is redun-dant, and not an ultimately sound object of scientific generalization or naturalized ontology, if it is generated by a pattern of greater computational power (lower logical depth).1 Then to be is to be a real pattern. Ladyman and Ross provide reconstructions of important concepts in philosophy of

1 The allusion here is to Charles Bennett’s (1990) idea of logical depth, which he proposes as a measure of complexity. The idea is roughly that complex objects have structures that are in each instance probably produced by long causal histories. A problem with Bennett’s definition for practical purposes is that it is not computable for a given data set (Ladyman,

science such as causation and laws in terms of recurrent types of structural relations among real patterns. Most important claims that have been thought to be laws in the history of modern science describe such structural relations in mathematical terms that survive episodes of theory change in approximate form. Individual objects as used by people for coordinating reference to a universe organized from specific parochial perspectives are real patterns of relatively high logical depth and thus do not feature in scientific generaliza-tions. Furthermore, the important real patterns in science are not reducible to facts about the intrinsic properties or natures of individual objects. Lady-man and Ross defend a metaphysics that does not take individual things to be fundamental (Ladyman, 1998 and 2002).

If metaphysics is to be part of the pursuit of objective knowledge, it must be integrated with science. Genuinely naturalized metaphysics must go beyond mere consistency with current science; it must be directly motivated by and in the service of science. The linked collection of institutions that constitutes science––its academic departments, research institutes, journals, and granting agencies––are the only ones dedicated to self-correcting pursuit of objective knowledge as their primary motiv-ational goal. Many other institutions of course gather knowledge; but only in science is it a decisive objection to a practice if onefinds that it makes knowledge accumulation subordinate to another goal.

Ladyman and Ross (2007) argue that making the world intelligible and comfortable using humans’ intuitive conceptual categories, which is argu-ably the primary goal of most non-naturalized metaphysics, is not only a different goal from that of contributing to objective knowledge, but also a systematically conflicting one. Van Fraassen (2002) agrees; a metaphysics that is not at least broadly true, he maintains, is worthless. Van Fraassen also believes that metaphysical truths cannot be aimed at with reasonable prospects of success––perhaps they could be obtained by luck, but then we wouldn’t recognize our good fortune––and so he concludes that metaphysics should be abandoned. The naturalistic metaphysician, by contrast, is optimistic about the possibility of bringing metaphysical hypotheses into closer conformity with objective reality to the extent that these hypotheses non-trivially unify bodies of established scientific know-ledge.

Lambert, and Weisner, forthcoming); but this issue doesn’t impugn the theoretical use to which we put it.

Many scientists rhetorically share van Fraassen’s pessimism, and express it in categorical terms when they publish reflections on the broadest explanatory ambitions of science. Stephen Weinberg (1992) argues that philosophy––by which he means both metaphysics and epistemology––is always unhelpful to science, and often impedes it outright by temporarily erecting barriers to progress through conservative allegiance to well-established concepts. Hawking and Mlodinow (2010) pronounce philo-sophical efforts to expound on the grand structure of reality‘dead’ and claim that physical cosmology has entirely supplanted philosophy’s former role. The meaning of these assertions is ambiguous, however. Weinberg and Hawking and Mlodinow in fact concede that unification of science to create comprehensive large-scale models of reality as a whole is a valued scientific objective––if not indeed the supreme such objective––but think that its institutional home has shifted from departments and journals called

‘philosophy’ to departments and journals called ‘physics’. They should thus be counted as among the sympathizers with naturalized metaphysics, their anti-metaphysical rhetoric notwithstanding.

Most popular naturalistic metaphysics produced directly by scientists is of low quality. In the case of Hawking and Mlodinow, it is egregiously sloppy.

Even if, as they maintain, the generalization of string theory by M theory unifies theoretical physics,2 it makes no evident promise of unifying the sciences in general, so could hardly supplant the whole of metaphysics.

Naturalistic metaphysicians may be disinclined to waste critical attention on such shallow efforts, and, if they are philosophers, the incentives of the academy support such fastidiousness. For good reason, work mainly aimed at popularizing knowledge is not a proper part of the scientific literature, but at best a second-order description of that literature.

Ladyman and Ross placed their 2007 brief for and outline of the contents of naturalistic metaphysicsfirmly within the polemical environ-ment of philosophy. Their almost complete lack of shared motivations or fundamental premises with non-naturalistic (analytic or, pejoratively,

‘neo-scholastic’) metaphysicians precluded constructive engagement with that part of the philosophical literature, though they did not shrink from destructive challenges to it. But they remainedfirmly inside the mansion of institutional philosophy by anchoring their arguments closely to recent

2 Following Smolin (2007) and others, we would bet against this speculation; and in any event speculation, running far ahead of empirical confirmation, it assuredly is.

themes in philosophy of science that have avowed or implicit metaphysical importance.

The discourse should not remain cloistered in this way, however.

Naturalized metaphysics, if it is to be a genuine contribution to know-ledge, should not mainly consist of borrowing from science to serve dialectics internal to institutional philosophy. Talk of naturalizing meta-physics is little more than hopeful rhetoric if the enterprise does not aim to play a reflexive role in guiding the formulation and elaboration of hypoth-eses that scientists actually investigate. Such positive influence on know-ledge is unlikely if, for the sake of connection with literature most scientists have not read, emphasis on themes such as the nature of causation crowds out interventions in specific theses promoted by scientists.

In this chapter, therefore, we reformulate the main conclusion of Ladyman and Ross (2007) in terms intended to provide better tools for application to scientific controversies. We build our rhetorical bridge by beginning with a famous philosophical slogan of Wittgenstein’s that many scientists will know, and of which some will approve. In the Tractatus Logico-Philosophicus (Wittgenstein, 1922: 5) Wittgenstein said that ‘The world is the totality of facts, not of things.’ This claim has doctrinal aspects in common with our view, specifically in calling attention to the onto-logical significance of structure; but the structure in question is logical rather than mathematical structure, and Wittgenstein certainly doesn’t deny that things are basic constituents of reality. We here adopt the form of address and twist it as follows to state our metaphysical thesis: the world is the totality of non-redundant statistics (not of things). The aim of the chapter as a whole is to say what we mean by this, and why we believe it.

The reader might reasonably doubt that this formulation should have any more resonance with scientific argument than the more abstract and dialectical presentation in Ladyman and Ross (2007). However, we will show that the issues are not parochial to philosophers by taking as our principal argumentive foil a recent effort by a leading theoretical physicist, David Deutsch (2011), to state a comprehensive philosophy of science, including strong metaphysical theses in our sense, motivated by unifying themes drawn mainly from three sciences: quantum physics, computation theory, and evolutionary theory. We will not attempt either a full expos-ition or a thorough assessment of Deutsch’s views. Rather, we use Deutsch’s philosophical opinions as a vehicle for doing two things. First, we aim to demonstrate the relevance of naturalistic metaphysics to some

current real controversies within science, as identified by an important scientist. Second, we aim to show how metaphysical considerations can inform scientific debate without becoming preoccupied with analysing concepts or language. This preoccupation is profoundly at odds with the point of naturalism, and is responsible for the barely disguised, or undis-guised, hostility with which many scientists regard philosophers.

Deutsch, like Ladyman and Ross (2007), emphasizes the ways in which science uniquely opens the way to limitless expansion of knowledge by disregarding parochial human intuitions about what ‘makes conceptual sense’. Innovations in science recurrently confound these intuitions, leading cultural expectations about what is‘reasonable’ to adapt and adjust.

Most philosophical commentary on science that is rooted in conceptual analysis amounts, even if inadvertently, to efforts at domesticating science and ultimately restricting its reach. Ultimately, we will criticize Deutsch for imposing an unwarranted restriction on his own understanding of the resources with which scientific activity engages with the general structure of reality. In particular, Deutsch cannot accept the possibility expressed by our pseudo-Wittgensteinian slogan above, and this in turn leads him to close off live options in fundamental physics through what, in our terms, amounts to a priori conservatism. In this he follows the consensus in the contemporary philosophy of physics literature, according to which one of several alternatives to Bohr’s original version of the Copenhagen inter-pretation of quantum mechanics must be favoured on the grounds that Bohr’s picture is so ‘incomplete’ as to be worthless. This situation reminds us that maintaining a truly consistent naturalistic attitude requires critical vigilance. Two thousand years of inherited philosophy tugs on our ankles, our cognitive inertial mass being our evolutionarily endowed perceptual systems with their attendant higher-level cognitive structure of physical objects, animals, and plants from which the philosophical system of Aris-totle was originally abstracted.3

The chapter proceeds as follows: in the next section we review relevant aspects of Deutsch’s philosophy; in section 3 we discuss standard realism

3 Another physicist who is led by his science into metaphysics and who also reaches a similar conclusion to us about its value when done through a priori analysis is Bernard d’Espagnat, who complains that science has shown that the ‘very notions that Aristotle and his followers got us into the habit of considering to be fully primary and basic’ are in fact anthropocentric (2006:1). We shall return to his views below.

and instrumentalism, and introduce Deutsch’s argument for incorporating Everett’s interpretation of quantum mechanics into metaphysics; in section 4 we discuss the metaphysics of quantum mechanics; andfinally in section 5 we present Peirce’s naturalistic embrace of the probabilistic modal structure he found in some science, and defend the claim that the world is fundamentally statistical.