Merleau-Ponty's Implicit Critique of the New Mechanists Benjamin Sheredos Abstract I argue (1) that what (ontic) New Mechanistic philosophers of science call mechanisms would be material Gestalten, and (2) that Merleau-Ponty's engagement with Gestalt theory can help us frame a standing challenge against ontic conceptions of mechanisms. In short, until the (ontic) New Mechanist can provide us with a plausible account of the organization of mechanisms as an objective feature of mind-independent ontic structures in the world which we might discover – and no ontic Mechanist has done so – it is more conservative to claim that mechanistic' organization is instead a mind-dependent aspect of our epistemic strategies of mechanistic explanation. Cite only the published version: this is a pre-print of an article published in Synthese. The final authenticated version is available online at: https://doi.org/10.1007/s11229-018-02006-7. This interim version of the article contains portions that were omitted from the final version, and lacks portions/revisions that were added in response to reviewer feedback. Acknowledgments I thank Rebecca Hardesty and Jason Winning for very helpful feedback on earlier drafts. [Re: the final version: I thank the editors and the anonymous reviewers for helpful feedback.] Some early work leading up to S2 of this paper was presented at the Gateway Graduate Conference at UMSL in March, 2014, and I'd like to thank the organizers: Matt DeStefano and Elliot Risch. Acknowledgments regarding the themes of S4.1 are made in Sheredos (2017). Finally, Bill Bechtel deserves thanks for initially steering me into and through the mechanism literature. *E-mail address: sheredos@ucsd.edu November 1, 2018 Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 2 1. Introduction In early work, New Mechanistic philosophers of biology seemed to promote what Wesley Salmon (1984a) called an ontic view of explanation. In an ontic view (roughly), the explanation of a phenomenon is, most fundamentally, the mind-independent ontic structure(s) in the world that causes, constitutes, or is otherwise responsible for the occurrence of the phenomenon. Ontic Mechanists hold that mechanisms are such structures. This view has been further articulated and promoted by Craver (2007, 2014). An alternative is what Salmon called an epistemic view, in which (roughly) explanations are, most fundamentally, mind-dependent strategies of making phenomena intelligible, predictable, or understandable. According to robust epistemic Mechanists, mechanisms are theoretically constructed as part of such a strategy (cf. Bechtel & Abrahamsen 2005, Bechtel 2015). Here I invoke the history of philosophy to articulate what is today a novel challenge to ontic Mechanists. First (S2) I argue that the ontic Mechanists' ontological commitment to mechanisms is equivalent to the the Gestaltists' commitment to what they called "physical Gestalten" – what I call "material Gestalten" (Köhler 1920; Koffka 1936).1 I show that Mechanists endorse a form of holism regarding mechanisms' organization and constitution. Just such holism, I argue, is what the Berlin Gestaltists highlighted when distinguishing material Gestalten from mere "and-summations." Mechanisms, if they exist in the world, are material Gestalten. I then (S3) show that this ontological commitment has been poorly understood by Mechanists themselves. In short, there is consensus that constitutive relations within organized mechanisms (between parts and whole) should be understood non-causally, but no ontological analysis of them has attained consensus. This leads to a puzzle: how can ontic Mechanists justify commitment to the holistic organization of mechanisms, when leading accounts of Mechanistic explanation seem offer no specification of what it is, exactly, to which we are allegedly ontologically committed? Finally (S4), I adapt Merleau-Ponty's argument against the Gestaltists to challenge the ontic Mechanists' understanding of our ontological commitment to material Gestalten. Merleau-Ponty's own argument involved claims which many authors today may not endorse, but I disentangle his core criticism. 1I focus on the Berlin School of Gestalt theory, not the Austrian school of von Ehrenfels and Meinong: see Smith (1988, p.150). Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 3 According to Merleau-Ponty's core criticism, we do not discover material Gestalten through scientific research, and conducting scientific research does not itself incur any ontological commitment to organized Gestalten. Instead, (a) we assume in advance that some of the systems we study should be understood as organized wholes, and (b) that assumption is never discharged by some scientific demonstration that it holds true. I claim that Merleau-Ponty helps us offer a diagnosis of why it has proven so difficult for the New Mechanists to provide any clear ontological account of mechanisms' organization: this ontological commitment cannot be spelled out in an ontic view of Mechanistic explanation, since it is presupposed by the ontic Mechanist from the outset. Moreover, I claim Merleau-Ponty helps us frame a moderate position which lets us evade the problem of analyzing mechanisms' organization. Absent any objective analysis of mechanisms' organization, we may more moderately maintain that such organization is simply a subjective feature of how we apprehend mechanistic phenomena: it is a mind-dependent feature of epistemic strategies of explanation, not a mind-independent feature of the world. The basic claims required for this view are essentially already expressed in strong forms of the epistemic view of Mechanistic explanation (cf. Bechtel 2015). Thus, exploring the historical engagement between Merleau-Ponty and Gestalt theory helps us frame a standing challenge against ontic conceptions of mechanisms. 2. Mechanisms are Material Gestalten In this section I argue that ontic mechanisms are material Gestalten. Bringing this to light requires completing three tasks. First (S2.1) I review a common conception of Gestalten as only perceptual-phenomenal entities. Second (S2.2) I re-introduce the under-appreciated notion of material Gestalten, and clarify the role they were intended to play in the Gestaltists' psycho-physical explanation of perceptual experience. As I shall clarify, the Gestaltists endorsed two claims as characteristic of all Gestalten: Holistic Individuation (HI): There exist parts and/or properties that are individuated only when they occur in some whole (i.e., as dependents parts of some Gestalt). Holistic Explanation (HE): There exist wholes (i.e., Gestalten) whose parts exhibit behaviors or properties which are only Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 4 explicable given properties of the whole.2 The Gestaltists held that HI and HE characterized not only the organized whole-objects of perceptual experience, but also the organization of material structures. Relations between these different varieties of Gestalten were key to the Gestaltist's proposed model of psycho-physical explanation. I do not intend to promote the Gestaltist's own view of psycho-physical explanation, but discuss it in some detail to clarify the basic features of material Gestalten: the question of whether there exist material Gestalten can be decoupled from the explantatory purposes to which Gestaltists put them. Finally I clarify foundational commitments regarding the organization of mechanisms, and I argue that the New Mechanists are likewise committed to HI (S2.3) and HE (S2.4): mechanisms are Gestalten. 2.1. Perceptual-phenomenal Gestalten In contemporary philosophy, "Gestalten" are typically understood as certain perceptual-phenomenal structures.3 For example, Grush4 provides the "illusory contours" figure below, then invokes a perceptual-phenomenal conception of Gestalten when he comments: "...the explanation would appear to be that something about the stimulus conditions triggers the perceptual system to construct a representation other than the one that accurately reflects what is being presented... The various Gestalt criteria can be given explanations in these terms... What this suggests is that the content of perceptual experience is not a mere passive registration of external events, but involves some degree of active construction..." (Grush, 2008, 150). 2I am indebted to Chudnoff (2013) for helping me see the distinction between HI and HE, though he does not frame it quite as I do. 3As illustration, the Cambridge Dictionary of Philosophy (1999) provides no general entry for "Gestalten," referring the reader to (i) an entry on figure-ground phenomena in perception, and (ii) a short bio of Köhler. 4I do not accuse Grush himself of having an over-narrow view of Gestalten. I simply borrow his claims to illustrate what such a narrow view would look like. Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 5 We can make limited headway in understanding the original conception of Gestalten using this case. First, recall the Gestaltists' thesis of HI: Holistic Individuation (HI): There exist parts and/or properties that are individuated only when they occur in some whole (i.e., as dependents parts of some Gestalt). HI is the claim that the individuation of some entities is dependent upon their role in a whole. Here "individuation" in meant in a metaphysical sense, not a cognitive or epistemic sense (Lowe, 2003). Epistemically, we individuate objects by distinguishing them from others – for disambiguation, I call this "identification." Metaphysically, an object is individuated by what makes it the object it is, distinct in its being from others. In our perception of this illusory contours figure, there is a straightforward sense in which HI holds true. Viewing the figure, we tend to experience a white square, flanked at each corner by occluded black circles. Experiencing the figure of a square requires experiencing its (illusory) edges. What is perceptually "filled in" appears (fleetingly) as edges-of-a-square, not free-floating "lines." The individuation of the edges as edges-of-a-square requires their participation in a whole square, in accordance with HI. I take it that this application of HI is relatively straightforward. HE is another matter: Holistic Explanation (HE): There exist wholes (i.e., Gestalten) whose parts exhibit behaviors or properties which are only explicable given properties of the whole Applied here, HE means that experiencing apparent edges is in some sense explained by properties of one's whole experience when viewing this figure. Grush sketches the more common approach: we explain the experience of edges by appeal to properties of the stimulus and of sub-personal processing. How might the Gestaltist invoke HE? As Chudnoff clarifies, the Gestaltists pursued a kind of phenomenological explanation, captured by the (somewhat cryptic) doctrine of the Law of Prägnanz (2013, p.176).5 The Law of Prägnanz holds that our perceptual experience tends to be as "good" (regular, symmetric, simplistic) as it can be, even if this requires that our experience be an inaccurate representation of stimuli. For the illusory contours 5I depart from Chudnoff in what follows: he discusses only phenomenal Gestalten. Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 6 figure, suppose an experience of a white square occluding four black circles is simpler than an experience of four un-occluded Pac-Man shapes oriented toward the center of the figure. If that were so, and if the Law of Prägnanz held good, we could invoke it to provide a kind of explanation (an answer to a why-question). Why do we experience illusory edges? Because that is part of the simplest whole-experience we can have, faced with this stimulus. On this view, "a property of the whole [experience] – greater simplicity in organization – explains a property of the part" (Chudnoff, 2013, p.176). 2.2. Material Gestalten In my view, the foregoing is not the full account of the Gestaltists' explanation of this case, and this is because a narrow, perceptual-phenomenal understanding of Gestalten does not fully capture the notion. In his Principles of Gestalt Psychology, Koffka introduced Gestalt theory as a new worldview which promised, among other things, (a) a new understanding of the nature of facts, theories and science, (b) a comprehensive integration of quantity, order, and meaning (value) into a unified ontology, and (c) a novel resolution of the materialist-vitalist debate in early 20th century biology.6 The notion of material Gestalten can be introduced in connection with this last issue. The Gestaltist aims to resolve the materialism-vitalism debate by showing that the kind of "order" which the vitalist claimed to uniquely characterize living systems is not unreal, not the result of some "vital force," but rather (in a basic form) already present in inanimate physical systems (Koffka 1936, p.17). This approach was pursued emphatically in Köhler's (1920) Physical Gestalten in Rest and Stationary State: the notion of Gestalten was extended to the material world itself, to characterize orderly systems at large. To illustrate this view, I sketch the Gestaltist's complete view of psycho-physical explanation. Recognizing material (more specifically, physical) Gestalten is construed as affirmatively answering the question "Are there physical whole-states or whole structures in which the parts are not mere and-summations [Undverbindungen]... of elementary individual states and individual structures?" 6In the materialist-vitalist debate, the materialist was often a classical mechanist: these must be contrasted with the New Mechanists who are my interlocutors here. Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 7 (Köhler, 1920, p.25/42).7 We can specify what this question (and its answer) amounts to by clarifying the concept of an "and-summation": "An aggregate [Zusammen] of 'parts' or 'pieces' is a pure 'summation' [eine reine "Summe"] only when its constituents may be added together one after another without thereby causing any alteration in any of them; and conversely, a summation is that kind of aggregate from which any one or more units may be removed without any effect either on the ones remaining or on the ones removed" (ibid., p.25/42). Where a collection is an "and-summation," the properties of the whole are merely summative, and can be understood in terms of: the intrinsic properties of the first item, and the intrinsic properties of the second item, and the intrinsic properties of the third... and so on. For example, the weight of a collection is equal to the weight of all the parts taken together. If all the collection's parts and properties work like this, it is a mere and-summation. Gestalten, in contrast, exhibit interdependence: a kind of conditioning or determination of parts' properties occurs in virtue of their role in the whole. Köhler's flagship examples of physical Gestalten concern electrostatic charges in circuits – cases chosen for their presumed applicability to neural systems. A simple case concerns a charged conductor. When charge is applied to an insulated conductor, the charge (i) distributes itself over the outer surface of the conductor, and (ii) attains equilibrium. The specific distributions which count as equilibria are determined by physical properties of the conductor. In a charged conductor which is, as a whole, at equilibrium, "it is impossible to decrease, increase, or displace any part of this charge alone; for with any such change there occurs a reaction throughout the entire natural structure" (Köhler, 1920, p.28/56). "In a word the structures of static charges upon conductors of given shape are physical Gestalten" (Köhler, 1920, p.28/68). HI applies, because the charge at any point p on a conductor c is only individuated (it only has the determinate properties it has) because the whole 7Citations to Köhler usually provide (i) pagination from the only existing partial translation, due to Ellis (1967), followed by (ii) pagination from the first German edition. Ellis employs significant editorializing, and while it is usually apt, I occasionally amend his translation. Occasionally I cite a passage which was not included in Ellis' translation, and there provide only the page-number from the original. Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 8 conductor is at equilibrium.8 The determinate amount of charge at any point p could be varied by applying more or less charge to the whole conductor and allowing it to attain equilibrium again. HE also applies. We can answer the question of why the charge at p is as it is by saying the whole conductor has attained equilibrium, given the applied charge. Explanation need not stop here, of course; we can proceed to explain how the conductor attains equilibrium in terms of the physical properties of the conductor, the movements of ions, etc. This does not diminish or counteract the holistic explanation in terms of equilibria. Köhler thought this model applied wholesale to the brain. Neurons were regarded as poorly-insulated conductors. When charged, a field of electrostatic forces would surround the neuron, forming a Gestalt. A number of such fields in interaction (e.g., in a region of the brain) would form a yet-larger whole-field: another, larger Gestalt. The whole brain would exhibit a field composed of myriad lesser Gestalten.9 Köhler suggested further that a naturalistic explanation of any experience (e.g., the perceptual-phenomenal experience of seeing an illusory figure) would depend upon their being some region of the brain exhibiting a material Gestalt of electrostatic forces whose structure was isomorphic to the structure of the experience. The perceptual tendency towards good form, captured by the Law of Prägnanz, would be mirrored by the electrostatic tendency towards equilibrium. This doctrine of isomorphism, in its simplest form, claimed: "actual consciousness resembles in each case the real structural properties of the corresponding psycho-physical processes" (Köhler, 1920, p.38/193). My argument does not require viewing this as a workable approach to psycho-physical explanation. I am concerned, initially, with the idea of a material Gestalt in its own right: it is a separate question whether this bit of Gestalt theory can be put to work in a naturalistic Gestalt psychology in the way Köhler envisioned. Likewise, it is irrelevant to my argument whether electrostatic phenomena should, in the final analysis, be counted 8Again, "individuation" is used in a metaphysical sense: see S2.1 above. 9I omit some historical details: initially Köhler held a more chemically-based view of neuronal function. Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 9 as material Gestalten.10 I am concerned only with what material Gestalten were supposed to be, as characterized by HI and HE. With this sketched, I turn to the New Mechanists. 2.3. Mechanisms as Gestalten: HI New Mechanistic accounts are heterogeneous, and there are many subtly distinct conception of mechanisms on offer. However, they all emphasize the organization of mechanisms as an important feature. While it has been overlooked, New Mechanists' claims about organization either flirt with or explicitly commit to the view that mechanisms are material Gestalten which satisfy the two conditions HI and HE. I approach HI in this sub-section, then discuss HE in the next. Machamer, Darden, and Craver offered one influential characterization of a mechanism: "Mechanisms are entities and activities organized such that they are productive of regular changes from start or set-up to finish or termination conditions" (2000, p.3). When a mechanism operates, a phenomenon of interest is produced. The aim of mechanistic explanation is to exhibit the "productive continuity" of the organized mechanism, making intelligible how the entities and actitivies which compose it jointly operate to produce the phenomenon. Beyond this, Machamer, Darden, and Craver say little to characterize mechanisms' organization. The organization of entities and activities "determines the ways in which they produce the phenomenon," and "entities must often be appropriately located, structured, and oriented, and the activities in which they engage must have a temporal order, rate, and duration" (ibid., p.3). If we dig deeper, we find them flirting with HI. The issue concerns the individuation of mechanisms and their parts. They maintain: "[On one hand:] Mechanisms are identified and individuated by the activities and entities that constitute them, by their start and finish conditions, and by their functional roles. 10Likewise, I do not claim that all material Gestalten are mechanisms. So it is not a problem if Glennan (1996, p.54) is right that electromagnetic fields cannot be mechanistically explained, in his sense. Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 10 [On the other hand, in the next breath:] Functions are the roles played by entities and activities in a mechanism. To see an activity as a function is to see it as a component in some mechanism... Functions... should be understood in terms of the activities by virtue of which entities contribute to the workings of a mechanism" (Machamer et al., 2000, p.6, my emph.). The first claim suggests that entities, activities, and their functions are individuated prior to entering into an organization to compose a mechanism. The parts' individuation does not depend upon the whole mechanism's organization, rather the whole mechanism is itself individuated on the basis of the entities composing it.11 The second claim, by contrast, suggests that no entity or activity has a function unless it is already a component of a mechanism which is organized to produce a phenomenon. This latter claim runs close to an endorsement of HI: no entity or activity possesses a function unless it is part of an organized whole which produces a phenomenon, for its function just is its contribution to the workings of the whole, and it cannot make such a contribution unless it is situated within that whole. Other New Mechanists likewise flirt with HI. Consider Glennan: "My analysis can be summarized by a definition... (M) A mechanism underlying a behavior is a complex system which produces that behavior by the interaction of a number of parts according to direct causal laws. Notice that (M) is a definition of a 'mechanism underlying a behavior' rather than a mechanism simpliciter. One cannot even identify a mechanism without saying what it is that the mechanism does. The boundaries of the system, the division of it into parts, and the relevant modes of interaction between these parts depend upon what behavior we seek to explain" (Glennan, 1996, 52). Elsewhere Glennan reasserts that "mechanisms are not mechanisms simpliciter, but mechanisms for behaviors" (2002, S344). This claim – sometimes called Glennan's Law – has been widely endorsed by New Mechanists 11MDC might here use "individuate" in an epistemic sense – see S2.1 above. This will not disturb my argument. Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 11 (cf. Glennan 2017, p.23-24; Illari & Williamson 2012, esp. fn.2 and p.134). If that is so, then plausibly – as Glennan seems to suggest in the tail-end of the passage above – the parts must likewise be understood not as "parts" simpliciter, but as as parts-of-a-whole-mechanism-for some behavior. This flirts with HI: the properties and interactions of parts that are genuinely relevant to the production of the behavior are features they exhibit only while in the organization of the whole system they compose. Take "the same parts" out of that organization, and they no longer interact and condition each other's properties. Whatever they might still do, they contribute nothing to the production of the behavior: they are no longer parts-of-a-mechanism-for that behavior. This "quick route" to HI through Glennan's Law might seem unconvincing. In early work, Glennan might seem to resist it: "...to prevent (M) from being vacuous... the parts of a mechanism must have a kind of robustness and reality apart form their place within that mechanism. It should in principle be possible to take the part out of the mechanism and consider its properties in another context. Care must be taken so that parts are neither merely properties of the system as a whole nor artifacts of the descriptional vocabulary. I shall summarize these restrictions by saying that parts must be objects" (Glennan, 1996, p.53). Note, however, that this does not fully evade HI. To treat parts as "objects" in this sense requires only that they have some continued existence, and exhibit some stable properties, outside of the organization of a mechanism. This is consistent with the possibility that the parts may have other properties only within the organization of a mechanism, per HI. In what follows, I argue that mechanism parts are claimed to have just such holisticallyindividuated properties, and that these properties are central to the (ontic) New Mechanists view. The underlying issue here concerns the extent of "decomposability" which is required of mechanisms, or the extent to which organization is permitted to condition parts' properties. Both Craver (2007, p.135) and Bechtel & Richardson (1993, p.25) appeal to the work of Wimsatt (1986, 1997) to characterize mechanisms' organization. Wimsatt articulated four conditions which characterize different varieties of aggregativity. A system is a mere aggregate, it is completely decomposable, if it meets all four conditions: Sheredos Merleau-Ponty vs. the New Mechanists Please cite only the version published in Synthese 12 1. Intersubstitutabilty of parts: rearranging and swapping parts doesn't influence the properties of the whole. 2. Qualitative similarity: the properties of the whole remain qualitatively similar (if quantitative, varying only in value) with addition or subtraction of parts. 3. Stability through decomposition and re-aggregation of parts: the properties of the whole remain invariant even if previously-independent parts are fused, and even if previously-linked parts are decoupled. 4. Minimal interactions among parts: there are no cooperative or inhibitory interactions among parts which influence properties of the whole.12 If a system is a mere aggregate, the specific organization of the parts contributes nothing significant to the features of the whole system: the whole is neatly decomposable into parts whose operations are self-determined. What Wimsatt calls a "mere aggregate" is quite clearly co-extensive with what the Gestaltists called an "and-summation." Where mere aggregativity (andsummation) is violated, we have a material Gestalt.13 According to New Mechanists, a prototypical mechanism is precisely not a mere aggregate. Craver (2007, pp.135-136) argues that mechanisms possess an "active organization" in virtue of which they violate all four conditions for mere aggregativity: a mechanism is not just "literally the sum of its parts" (Craver 2007, p.135; see also Glennan 2017, p.23). Bechtel & Richardson (1993, pp.26-32) claim that pursuing mechanistic explanation begins with fallible heuristics of decomposition and localization, which presume that some degree of decomposability is possible, hence that the mechanism under investigation possesses some form of aggregativity. However, they endorse the 12Wimsatt's (1986) original presentation was adapted by Bechtel & Richardson (1993, p.25). Wimsatt's (1997, p.S376) more concise presentation was adapted by Craver (2007, p.135). My adaptation here draws inspiration from all these sources. 13I am pursuing a conceptual argument that mechanisms' organization makes them material Gestalten. There may also be a more direct historical connection. Wimsatt (1986, p.289) acknowledges that his view of aggregativity was likely influenced by disagreements with Ernest Nagel's "Wholes, sums, and organic unities" (1952; rpt. in The Structure of Science). Nagel's piece explicitly opposes Köhler's conception of physical Gestalten. When New Mechanists borrow Wimsatt's anti-Nagelian view to clarify the nature of mechanisms' organization, they implicitly borrow, second-hand, a Gestaltist view.