Taking the Metaphysics of Knowledge Seriously: A Response to Sven Bernecker's "On the Metaphysics of Knowledge" Joachim Horvath University of Cologne September 6, 2013 Final Version1 In his "On the Metaphysics of Knowledge" (this volume), Sven Bernecker introduces and defends a novel account of knowledge that he calls 'identificationism'.2 In fact, Bernecker's account is a hybrid view that combines a modal tracking condition – some variation on safety and/or sensitivity – with his original identificationist condition. The reason for including a tracking condition is that some Gettier cases, like the famous fake barn case,3 are best accommodated in this way. In making this more familiar claim, Bernecker follows epistemologists like Nozick, Sosa, or Pritchard.4 But he also adds the less familiar claim that there are 'intractable' Gettier cases that cannot be dealt with by a tracking condition alone. These intractable cases involve necessary or modally stable propositions, such as 2+2=4 or there is carbon on earth,5 which are either true in all possible worlds, or at least true in all possible worlds that are close to the actual world. Now consider the safety condition on knowledge, which says that a knowledge--‐ constituting belief could not easily have been false.6 This condition is trivially satisfied in the case of necessary or modally stable propositions, and thus it cannot provide for a 1 Forthcoming in Markus Gabriel, Wolfram Hogrebe & Andreas Speer (eds.), Das neue Bedürfnis nach Metaphysik – The New Desire for Metaphysics, Berlin: Akademie Verlag. 2 See also Bernecker, Sven (2011) "Keeping Track of the Gettier Problem." Pacific Philosophical Quarterly 92: 127–152. 3 Cf. Goldman, Alvin (1976) "Discrimination and Perceptual Knowledge." The Journal of Philosophy 73: 771–791. 4 Cf. Nozick, Robert (1981) Philosophical Explanations. Cambridge, Mass.: Harvard University Press; Sosa, Ernest (1999) "How to Defeat Opposition to Moore." Noûs 33: 141–153; Pritchard, Duncan (2005) Epistemic Luck. Oxford: Oxford University Press. 5 Cf. Horvath, Joachim (2008) "Testimony, Transmission, and Safety." Abstracta 4: 27–43. 6 Cf. Sainsbury, R. M. (1997) "Easy Possibilities." Philosophy and Phenomenological Research 57: 907–920; Sosa (1999). 2 satisfying general account of knowledge. Bernecker (this volume) shows convincingly that one can construct Gettier cases that involve modally stable propositions, which thus turn out intractable for modal tracking conditions alone. That is why Bernecker thinks that an identificationist condition must be added to one's preferred tracking account of knowledge. How does Bernecker's identificationism make progress on this problem? The identificationist condition on knowledge requires that one's reasons for believing that p represent some fact(s) that are identical with, or grounded in, or causally related to the truthmaker of p. For example, if Peter happens to believe the necessary proposition the 100th prime number is 541 based on the testimony of his guru, then Peter's belief trivially tracks the truth that the 100th prime number is 541. But it seems clear that Peter's reason for holding this belief – that his guru said so – does not identify the truthmaker of the proposition the 100th prime number is 541. For, neither is the guru's testimony causally related to the abstract mathematical fact that the 100th prime number is 541, nor does Peter's reason – that his guru said so – represent anything that might plausibly be regarded as a truthmaker, or as something that is grounded in the truthmaker, of the proposition the 100th prime number is 541. Thus, identificationism does not count Peter's guru--‐inspired true belief as knowledge.7 In this way, Bernecker (this volume) tries to accommodate all intractable Gettier cases with his identificationist condition, which therefore seems prima facie well motivated from an epistemological point of view. In this paper, I will not directly address the epistemological adequacy of Bernecker's identificationism. Rather, I want to focus on the substantial metaphysical commitments that it incurs, in particular on the problematic idea that our epistemic reasons identify the truthmaker of our respective belief when we know something. My conclusion will be that being a truthmaker for p is metaphysically more demanding than being an epistemic reason for p. A truthmaker for p must necessitate the truth of p, while an epistemic reason for p must merely indicate the truth of p. Thus, we should not expect that epistemic reasons identify the truthmakers of our knowledge--‐constituting beliefs in the way that Bernecker suggests. 7 Even though this verdict is correct in the case at hand, it might be a problem in many good cases of testimonial belief--‐acquisition. Suppose that Peter learns that the 100th prime number is 541 on the basis of the testimony of a world--‐leading expert on prime numbers. Intuitively, this should count as a case of knowledge, but it is not clear to me that Bernecker's identificationist condition is satisfied here. 3 To make the following discussion more precise, let me first state the complete identificationist account of knowledge (cf. Bernecker, this volume): Necessarily, S knows that p iff: a) S believes that p, b) p is true, c) S's belief that p tracks the facts, d) S's reasons for believing p identify the truthmaker of p. Conditions a) and b) are standardly accepted by most epistemologists. The addition of some tracking condition c) is also widely accepted. At any rate, tracking conditions will not be discussed further in this paper. Rather, my sole focus is on the metaphysical implications of the identificationist condition d). The following explication of d) should be helpful to bring out these implications (cf. Bernecker, this volume): (IC) Necessarily, if S knows that p, then S's reasons for believing p (i) represent the truthmaker T of p or facts that are grounded in the truthmaker T of p, or (ii) represent facts that are causally related to T. Let me begin with a little metaphysical quibble. Subcondition (ii) of (IC) commits identificationism to the claim that facts or states of affairs can be the relata of causal relations. But the standard view in the metaphysics of causation is that the relata of causal relations are events.8 Therefore, identificationism is apparently committed to a non--‐standard view about the relata of causation. Since the main motivation for identificationism is epistemological, such a non--‐standard metaphysical commitment would seem to require an explicit metaphysical defense, which Bernecker does not provide. But maybe this is only a technical problem, and I suspect that there must be some way to adjust the identificationist condition accordingly. However, there is a deeper worry here. It seems that the answer to the following two distinct metaphysical questions must be compatible from an identificationist point of view: what are the relata 8 Cf. Schaffer, Jonathan (2008) "The Metaphysics of Causation." In: The Stanford Encyclopedia of Philosophy, Edward N. Zalta (ed.), Fall 2008. URL = <http://plato.stanford.edu/archives/fall2008/entries/causation--‐metaphysics/>. 4 of causation, and what are the relata of the truthmaking relation? For otherwise, it might easily turn out that subcondition (ii) of the identificationist condition (IC) is impossible to satisfy. I now want to turn to a more pressing problem that concerns the metaphysics of truthmaking. The basic idea of truthmaker theory is that truthmakers necessitate the truth of the propositions that they make true. So, a proposition p cannot fail to be true when there is a truthmaker for it.9 For example, when it is a fact that Bonn lies on the Rhine, the proposition Bonn lies on the Rhine cannot fail to be true. However, truthmaking is not always so straightforward. For example, consider the proposition there are elephants. It might be tempting to say that this proposition is made true by the fact that there are elephants, in complete analogy to the case of Bonn lies on the Rhine. But first, it is not clear whether we should accept the existence of general facts, such as the fact that there are elephants. And second, there already are enough particular facts that could serve as a truthmaker for the proposition there are elephants, such as the fact that a particular elephant, Marlar, lives at the Cologne Zoo. In accordance with the basic idea of truthmaker theory, the proposition there are elephants cannot fail to be true when it is a fact that Marlar lives at the Cologne Zoo. And the same holds for numerous further facts about Marlar and other elephants. It is therefore a common view in the truthmaker debate that that every particular fact about elephants is a truthmaker for the general proposition there are elephants.10 Now suppose that you know that there are elephants based on your perceptual awareness of Marlar when you visit the Cologne Zoo. Your perceptual reason then identifies one of the truthmakers of the proposition there are elephants, for example the particular fact that Marlar is taking a bath. But your perceptual reason clearly does not identify the truthmaker of that proposition, because there are many truthmakers for that proposition, namely all the particular facts about elephants. And these particular facts about elephants, such as the fact that Marlar is taking a bath, are also not mutually grounded in each other – if only because grounding is an asymmetrical relation (see below). For these reasons, the identificationist condition d) seems to rule out that you can know that there are elephants based on your perceptual awareness of Marlar, and the same holds for many other ordinary cases of existential knowledge. 9 See e.g. Fox, John F. (1987) "Truthmaker." Australasian Journal of Philosophy 65: 188–207. 10 Cf. Armstrong, David (2010) Sketch for a Systematic Metaphysics. Oxford: Clarendon Press. 5 One might argue that this problem for identificationism is just another technicality that can easily be avoided by the following slight modification of (IC): (IC*) ... (i*) represent at least one of the truthmakers of p or ... Fair enough. But the present problem still shows that one cannot even formulate identificationism correctly without paying close attention to the details of the metaphysics of truthmaking. In a way, that was just a metaphysical warm--‐up exercise, however, for the following problem cannot be dealt with so easily. Consider the proposition there are no witches. Since Russell's famous rejection of negative facts,11 only very few philosophers were willing to embrace their existence.12 For this reason, it is one of the standard views about the truthmakers of negative propositions that they are made true by the totality of all positive facts plus a "that's all"--‐ fact.13 So, when the totality of all positive facts does not contain any facts about witches, and the "that's all"--‐fact ensures that these are all the facts there are, then the proposition there are no witches cannot fail to be true. Let us assume, plausibly enough, that we know that there are no witches. How do we know that there are no witches, that is, what are the reasons that we typically have for believing this proposition? It is probably some fairly complicated combination of perceptual observation, historical information, and scientific knowledge. But no matter how complex and comprehensive our reasons for denying the existence of witches may be, they surely do not (iw) represent the truthmaker of the proposition there are no witches, for they clearly fall short of representing the totality of all facts. And they also need not identify something that is grounded in the totality of all facts, in particular when our reasons represent certain metaphysically fundamental facts that are not grounded in anything else, e.g. facts about the laws of nature. And our reasons also do not (iiw) represent any facts that are causally related to the totality of all facts. But that seems to make knowledge of negative propositions impossible on the identificationist view, at least for finite beings like us. Let me briefly argue for (iw) and (iiw), i.e., for the claim that identificationism rules out that we can have knowledge of negative propositions like there are no witches. 11 Cf. Russell, Bertrand (1919) "The Philosophy of Logical Atomism." The Monist 29: 190–222. 12 But see e.g. Beall, JC. (2000) "On Truthmakers for Negative Truths." Australasian Journal of Philosophy 78: 264–268. 13 Cf. Armstrong, David (1997) A World of States of Affairs. Cambridge: Cambridge University Press. 6 The first part of subclaim (iw) is more or less obvious, because as finite beings we simply cannot represent the totality of all facts, which would include facts about the distant past or facts about events that lie outside our light cone. But what about the second part of subclaim (iw), i.e., the claim that our reasons for believing that there are no witches represent facts that are grounded in the totality of facts? We may distinguish between a liberal and a strict conception of facts here. On a liberal conception, every true positive proposition would correspond to a fact. Then, all of the facts that our reasons represent would actually be included in the totality of facts. But since grounding is an asymmetrical relation of metaphysical priority,14 nothing can be (partly) grounded in itself. So, the facts represented by our reasons cannot be grounded in the totality of facts, since that totality partly consists of those very facts. On a strict conception of facts, however, only fundamental truths about the world correspond to genuine facts, e.g. truths like 'electrons are negatively charged'. Given such a strict conception, many of our reasons for believing that there are no witches would, strictly speaking, not even represent any genuine facts. Nevertheless, one could probably still say that these reasons identify certain truths that are grounded in the fundamental facts. However, some of our reasons for denying the existence of witches might represent basic laws of nature that speak against the existence of witchcraft. Therefore, these reasons cannot identify something that is grounded in the totality of all facts, because even on a strict conception, facts about basic laws of nature might arguably be included in the totality of facts, and so we get the same problem as before. Why is subclaim (iiw) true as well? The argument for (iw) shows that our reasons R for believing that there are no witches can at most represent a proper subset S of the totality of all facts T. So, the totality T of all facts includes the facts S that our reasons represent. But given that the facts S are included in T, they can neither cause nor be caused by T, and so S and T cannot be causally related to each other, as subcondition (ii) of (IC) would require. For, if two (sets of) facts are causally related, they must be metaphysically distinct, because no (set of) fact(s) can figure as a cause of itself, not even partly. The fact that, for example, my computer is broken cannot be caused by the fact that my computer is broken, and it also cannot be caused by the fact that my computer's CPU is broken. The latter fact may (partly) constitute the fact that my computer is 14 See e.g. Correia, Fabrice, and Benjamin Schnieder (2012) "Grounding: An Opinionated Introduction." In: Metaphysical Grounding: Understanding the Structure of Reality, Fabrice Correia and Benjamin Schnieder (eds.), 1–36. Cambridge: Cambridge University Press. 7 broken, but it clearly seems wrong to say that the breakdown of my computer's CPU caused the breakdown of my computer. Rather, my computer's breakdown just is or (partly) consists in the breakdown of its CPU. Now, given that the facts S are included in the totality of facts T, these two sets of facts are not metaphysically distinct. For this reason, S and T cannot be causally related, and so subclaim (iiw) is true as well. In fact, the same problem arises for knowledge of general truths, like all humans are mortal, which are logically equivalent to negative truths. All humans are mortal, for example, is equivalent to there is no human that is not mortal. The present problem thus concerns large swaths of our ordinary knowledge about the world, and so Bernecker's identificationism threatens to have serious skeptical implications. This runs counter to the project of providing a philosophical analysis of knowledge in the ordinary sense, which Bernecker – along with most other contemporary epistemologists – is clearly engaged in (cf. Bernecker 2011). Therefore, it seems that identificationism stumbles on the very metaphysical apparatus of truthmaking that it relies on in order to solve an especially difficult epistemological problem. Let me offer a tentative diagnosis of the mismatch between epistemic reasons and truthmakers that besets the identificationist proposal. For simplicity, let us assume factualism about epistemic reasons,15 understood as the view that an epistemic reason R is a fact that makes the truth of some proposition p epistemically probable. On any non--‐ skeptical view about epistemic reasons, such a reason R will typically not make the truth of p certain, or eliminate all possibilities of error concerning p. Rather, R will only make the truth of p more likely than the falsity of p (to some degree smaller than 1). In other words, an epistemic reason R will merely indicate the truth of the relevant proposition p more or less strongly, but it will fall short of necessitating the truth of p. In contrast, a fact T that figures as a truthmaker for p does indeed necessitate the truth of p. For this reason, the facts that constitute epistemic reasons for holding p true will typically not be identical with, and also not be necessarily grounded in, the facts that constitute truthmakers for p – which thus explains the mismatch between epistemic reasons and truthmakers that plagues the identificationist proposal. One might object that the specific assumptions about truthmakers that I have made above are anything but mandatory. Therefore, I have clearly not ruled out that 15 See e.g. Parfit, Derek (2001) "Rationality and Reasons." In: Exploring Practical Philosophy: From Action to Values, Dan Egonsson, Jonas Josefsson, Björn Petersson, Toni Ronnow--‐Rasmussen, and Ingmar Persson (eds.), 17–39. Burlington, VT: Ashgate. 8 there is some plausible understanding of the metaphysics of truthmakers that perfectly fits the identificationist proposal (cf. Bernecker, this volume). Once again, this is fair enough. But it does not affect the wider point that I want to make here, namely that any serious defense of identificationism requires a detailed discussion of the metaphysics of truthmaking. Without that, it will always remain a live possibility that identificationism really has the troublesome skeptical consequences that I have pointed out above. In conclusion, I want to briefly bring out some of the metaepistemological implications of the preceding discussion. One methodological lesson might be that epistemological theorizing should aspire to be as metaphysically neutral as possible, in particular with respect to controversial metaphysical "tools" such as truthmaking, grounding or modal closeness. However, I doubt that much of substance would remain of epistemology if one did really try to maintain such a far--‐reaching metaphysical neutrality. To the contrary, my view is that the theory of knowledge simply falls into place as a chapter of metaphysics. One important reason is that standard philosophical definitions of knowledge are best understood as claims about the essence of knowledge, and thus as metaphysical claims through and through.16 Therefore, the problem with Bernecker's identificationism is not that it is too metaphysical, but rather that it is not metaphysical enough. In other words, Bernecker does not yet take the metaphysics of knowledge seriously enough, for that would require a detailed examination of the metaphysical underpinnings of identificationism, in particular of the metaphysics of truthmaking, grounding, and causation. It goes without saying that the present attempt at making some progress in this direction is at best a prolegomenon to any serious metaphysics of knowledge, identificationist or otherwise.17 16 Cf. Horvath, Joachim (2011) In Defense of Conceptual Analysis. Dissertation: University of Cologne. 17 For very helpful comments and discussion I would like to thank Sven Bernecker, Thomas Grundmann, Dolf Rami, Peter Schulte, and my audience at the 2nd Bonn Humboldt Award Winners' Forum "The New Desire for Metaphysics" in October 2012 in Bonn.