Log in / Register
Home arrow Psychology arrow Metaphysics and the philosophy of science : new essays

The naturalist club

Demarcation projects in philosophy have a checkered history. This fact is not lost on proponents of naturalized metaphysics, as they have faced many of the same difficulties in calibrating a principled and defensible criterion for naturalistically acceptable metaphysics between uninterestingly weak and implausibly strong endpoints. Sometimes, as Penelope Maddy points out, naturalism marks out “little more than a vague science-friendliness”; in order to qualify as unnaturalistic, one would have to insist—quite radically—that, for example, “metaphysical intuitions show quantum mechanics to be false” (2007, 1). Even the most imperialistic metaphysicians would abjure that level of science-unfriendliness.

How else might naturalists ratchet up the requirement of “science friendliness”? Another possibility would be to limit the range of acceptable metaphysical projects, for example, those involved in reading off metaphysical theses from scientific theories. Anjan Chakravartty offers some examples: “what ontology of objects and processes is described by the mathematical formalism of theories in fundamental physics [or, we might add, from the special sciences]? Is natural selection a force that acts on some or other biological entity, or is it simply a statistical outcome of causal interactions acting at other levels of description?” (2013, 31). Other naturalists play variations on this basic theme. Ritchie’s (2008) “Deflationary Methodological Naturalism,” for instance, emphasizes the need for continuity between metaphysics and particular scientific projects, but at the same time cautions against drawing rich philosophical theses (such as physicalism, realism, etc.) from these scientific projects. Morganti offers naturalistic metaphysicians a choice: one should “only do metaphysics as long as it can be immediately applied for the interpretation of science or, alternatively, develop metaphysics independently and then seek application of parts of it” (2013, 22).

On reflection, however, it seems doubtful that mere restrictions to a certain range of projects will ensure a robustly naturalistic orientation. Consider Ladyman and Ross’s examples ofanalytic metaphysicians drawing conclusions about the fundamental mereological atoms that “[lack] any basis in contemporary science” (2007, 19). They might be engaged in a project that overlaps considerably with those pursued by particle physicists. But if the thesis that there are “extended simples,” for example, turns out to conflict with quantum mechanics, then, topical cohesion aside, these metaphysicians might feel justified in arguing for the falsity of one of the most empirically successful scientific theories in human history![1] More than simply asking the same questions or operating in the same domain, a full-blooded metaphysical naturalist would also want to insist on a tighter connection between science and metaphysics.

But what should the nature of this connection be? Should metaphysics be relegated to serving as a “handmaiden” to the sciences (cf. Paul 2012), dedicated to merely working out the ontological commitments of our best theories (as Chakravartty’s first example illustrates)? Should our metaphysical theories derive exclusively and directly from scientific conclusions? Should methods used in metaphysics be modeled on those used in science? Prominent naturalists have tended to broach such questions by criticizing actual metaphysical practice. For example, Ladyman and Ross criticize the emphasis by analytic metaphysicians on satisfying a prioristic intuitions as a key desiderata in theory construction and confirmation.[2] We can identify two related worries here. First, it is not clear how we might go about vindicating the general reliability of these intuitions. Second, we seem to have some reason to doubt their reliability. Ladyman and Ross argue that science has been a consistent source of surprise in precisely the sense that we habitually discover that our intuitive judgments about the world are wrong; we allow science to show us this (2007, §1.2.1). Given that preserving and systematizing these intuitions is not—and should not be—emphasized in science, why should things be any different in metaphysics ?[3] Pointed questions like this, coupled with cautionary tales of theses proffered as necessarily true turning out to be actually false, are sometimes interpreted as showing that we ought to have metaphysics either defer to the deliverances of science or adopt its methods.

But there are many forms that such deference can take. It can be absolute, in something like the way that some Logical Positivists envisioned, perhaps leaving no room at all at the intellectual table for metaphysics. Or naturalists can identify some scope for a suitably reformed metaphysics to contribute to respectable discourse, in which case the question is how it should be reformed and constrained. Maclaurin and Dyke contend that the central problem with non-naturalistic metaphysics is that (when it makes ontological claims that extend beyond mere conceptual analysis) it “achieves no practical benefit because [non-naturalistic metaphysical theories like mereology] have no observable consequences” (2012, 301). Correspondingly, they allow that metaphysical debates that do have observable consequences will be naturalistically acceptable.[4]

There does seem to be something to the frustration felt by many naturalisti- cally inclined philosophers that many metaphysical debates appear to be empirically inert. But it has proven difficult to formulate and justify a precise principle of deference that avoids both triviality and the unintentional imposition of implausibly strong constraints on science—one might regard observability and practical benefit as fraught concepts, after all.[5] Ladyman and Ross attempt to give naturalized metaphysics specific content by defending a rather uncompromising series of principles, “referenced to the institutional factors that make science epis- temically superior” (2007, 34). One such principle is the Principle of Naturalistic Closure (PNC):

Any new metaphysical claim that is to be taken seriously at time t should be motivated by, and only by, the service it would perform, if true, in showing how two or more specific scientific hypotheses, at least one of which is drawn from fundamental physics, jointly explain more than the sum of what is explained by the two hypotheses taken separately. (37)

The PNC distinguishes acceptable from unacceptable metaphysics by placing a different kind of topical constraint on acceptable metaphysics: it should only concern itself with a certain kind of scientific unification project.

I cannot do justice here to Ladyman and Ross’s defense of this thesis; in brief, it turns on this unification project being a worthy enterprise that is not credibly left to any particular branch of science (and thus something that metaphysics could pursue without gross epistemic negligence). But as Melnyk points out, that this is a legitimate philosophical niche for metaphysics to fill does not entail that it is the only

such niche (2013, 82-83). Nor does it seem obvious that fundamental physics ought to be so prioritized.[6]

Rather than seeing naturalistic deference as leading to a constraint on legitimate goals or topics of concern, one might see it instead as a sort of high-level methodology comprising a general encouragement to premise one’s philosophizing on developments in relevant sciences (or using their methodological tools) together with a “science-first” policy for conflict resolution: namely, resolve all apparent conflicts between metaphysics and science by siding exclusively with science. This sort of “meta-methodology” would presumably only be regarded as a necessary condition of naturalistic metaphysics. Ladyman and Ross hint at something of this flavor in the lead-up to their statement of the PNC:

Since science just is our set of institutional error filters for the job of discovering the objective character of the world—that and no more but also that and no less—science respects no domain restrictions and will admit no epistemological rivals (such as natural theology or purely speculative metaphysics). With respect to anything that is a putative fact about the world, scientific institutional processes are absolutely and exclusively authoritative. (2007, 28)[7]

Much more could be said by way of explicating and justifying different approaches to naturalistic metaphysics. But let us take this as a key naturalistic commitment and see how it plays out in the context of the discussions of the metaphysics of species.

  • [1] Conflicts of this sort can, of course, also arise from a simple lack of awareness rather than any outright hostility to science (or eagerness to see its claims refuted). We might place under this heading the early biologicalessentialists—apparently science-friendly in disposition—who assumed that biological species would be likechemical species in possessing some “deep-lying” microstructural essence. (How we should think of modern“scientific essentialists” more generally vis-a-vis naturalism, I leave to another occasion.) In any case, a certainlevel of ignorance can seem like willful disdain given the relative ease with which relevant science might bebrought to bear on the metaphysics in question (Ladyman and Ross 2007, 5; Humphreys 2013, 56). A trickyquestion is how to characterize the proper kind of attention to recent scientific developments.
  • [2] See also Ladyman’s chap. 7 in this volume.
  • [3] I am merely presenting, not advocating, this line of thought. For two different kinds of critical discussions ofLadyman and Ross on the role of intuition, see Dorr 2010; and Maclaurin and Dyke 2012, §4.
  • [4] They offer the debate about the philosophy of time as an example; see Katherine Brading’s chap. 1 in this volumefor one way in which this might play out.
  • [5] For critical discussion of Maclaurin and Dyke along these lines, see McLeod and Parsons (2013)—to whichDyke and Maclaurin (2013) respond.
  • [6] I do not pretend that these comments add up to a strong argument against the PNC; pursuing this thread further, however, would take us too far afield from my present concerns. For more detailed critical discussion anddefense, see the chapters in this volume by Waters and Ladyman.
  • [7] I take “no epistemological rivals” in a weaker sense than it was perhaps intended to imply the science-first policyof conflict-resolution.
Found a mistake? Please highlight the word and press Shift + Enter  
< Prev   CONTENTS   Next >
Business & Finance
Computer Science
Language & Literature
Political science