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A Modified Conception of Mechanisms


In this paper, I critique two conceptions of mechanisms, namely those put forth by Stuart Glennan (Erkenntnis 44:49–71, 1996; Philosophy of Science 69:S342–S353, 2002) and Machamer et al. (Philosophy of Science 67:1–25, 2000). Glennan’s conception, I argue, cannot account for mechanisms involving negative causation because of its interactionist posture. MDC’s view encounters the same problem due to its reificatory conception of activities—this conception, I argue, entails an onerous commitment to ontological dualism. In the place of Glennan and MDC, I propose a “modified conception” of mechanisms, which (a) obviates the problem of negative causation by reinterpreting MDC’s activities according to a “descriptivist” account, and (b) avoids MDC’s problem by postulating a monistic ontology of entities. Thus, by solving these problems, my modified conception offers a cogent, more adequate alternative to Glennan’s and MDC’s conceptions of mechanisms.

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  1. See Pietroski and Rey (1995).

  2. I do not discuss William Bechtel’s parts/operations conception in this paper, although it is, at least in certain respects, very similar to the modified conception that I enunciate in Sect. 5.

  3. See Pietroski and Rey (1995) for discussion.

  4. Incidentally, Woodward argues that the dichotomy between laws and accidental generalizations is spurious and ought to be abandoned.

  5. As Craver points out, the use of variables as causal relata is advantageous because a wide variety of possible relata—events, processes, objects, etc.—can be converted “without loss” into talk of variables (Craver 2007a, p. 95).

  6. I follow Craver in understanding causal relata as contrasts, and thus the adicity of causal relations to be four (Craver 2007a, pp. 82–83).

  7. Personal communication.

  8. As I suggest below, Glennan (2002) appears to renounce his 1996 anti-fundamentalism about causation by adopting Woodward’s manipulability theory of causation, although the two are not necessarily incompatible.

  9. As I discuss below, following Craver I consider instances of inhibition to be negative causes. Indeed, inhibition, in contrast to “omission,” falls within the category of “prevention.” Prevention occurs when C causes not-E; not-E in turn is identical to not-C that causes E. In this way, inhibition is causally negative. Neural networks exhibit inhibition when one neuron hyperpolarizes another, thereby preventing it from firing. See Craver (2007a, pp. 6, 80–81) for more.

  10. Lindley Darden (personal communication) argues that MDC’s conception can account for cyclical mechanisms. The only difference between these and linear mechanisms is that one must more or less arbitrarily select start and termination conditions, e.g., the Krebs cycle starts with isocitrate rather than α-ketoglutarate, or succinate rather than fumarate.

  11. Craver similarly characterizes his project in Explaining the Brain as consisting of a descriptive, and then normative step (Craver 2007a, p. viii).

  12. Lindley Darden envisages a “completely static” and “frozen world” without activities (Darden 2006, p. 278; see footnote).

  13. Machamer states in the very next sentence: “This is the dualistic position that [MDC] put forth” (Machamer 2002).

  14. There is considerable confusion among philosophers about the ontological status of MDC’s activities. Many seem to think, like Tabery, that activities do not constitute a distinct ontological category. This is simply false, as both careful readings of MDC’s paper and personal communication with its authors verify. Indeed, as Darden puts it in personal communication, MDC’s dualism is a radical break from the inveterate tradition of substantivalism.

  15. Although activities are slightly different in character than processes, the former is derivative of the latter.

  16. This has been confirmed through personal communication. The idea, I think, was to disencumber the notion of causation from the heavy connotations (and whatever other semantic baggage) that the term carries with it, and to do this by introducing into the philosophical lexicon a novel term.

  17. MDC would agree, I think, that their dualist ontology is “onerous.” Indeed, this is precisely why they feel the need, as they say, to “justify this break with parsimony, this dualism of entities and activities” (MDC 2000, p. 4; emphasis added), by arguing for their conception’s ontic, descriptive, and epistemic adequacy.

  18. Spontaneous processes may result not just from negative causes (such as in LTP), but also from positive causes; for example, the presence of salt may be responsible for the entropic movement of water across a cell membrane.

  19. To be clear, even in the case described in footnote 15, there still would be no interaction between the salt and the water.

  20. Darden says essentially the same thing: “Interaction between two entities is a kind of activity, conceived in a more entity-centered way and missing the productive nature of activities in general” (Darden 2006, p. 277; my emphasis). Although I disagree with the second statement that interactions miss the productive nature of activities (see Sects. 2 and 5), Darden and I concur that interactions are a subset of activities. Furthermore, an etymological parsing of ‘interaction’ corroborates my contention: ‘inter-’ meaning between and ‘action’ or activity.

  21. This interpretation is similar in many respects to Craver’s “deflationary” view of activities (Craver 2007b).

  22. See Craver (2007a) for discussion about mechanism levels.

  23. That is, understood as reified causes.

  24. As Tabery (2004) indicates, Machamer first suggested the term.

  25. I obviate this category mistake with my descriptivist interpretation of activities, which explicitly relieves activities of their ontological baggage.

  26. I thank an anonymous referee for this example.

  27. The term ‘direct’ here simply signifies that there is no intervening activity on that mechanism level between an entity and its behavior or two entities and their interaction.

  28. See Craver (2007a, p. 82), for a more detailed analysis.

  29. ‘Genuinism’ is Phil Dowe’s coinage (Dowe 2004).

  30. Note that Craver also discusses inhibition as negative causation (Craver 2007a, pp. 6, 81).


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I would like to thank an anonymous referee, Stuart Glennan, Christopher Cherniak, Mathias Frisch and Carl Craver for helpful feedback. Special thanks to Lindley Darden for many insightful comments on earlier drafts.

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Correspondence to Phillip J. Torres.

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Torres, P.J. A Modified Conception of Mechanisms. Erkenn 71, 233–251 (2009).

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  • Property Change
  • Ontological Commitment
  • Mechanism Description
  • Modify Conception
  • NMDA Channel