Coherence and Reliability: The Case of Overlapping Testimonies

A measure of coherence is said to be reliability conducive if and only if a higher degree of coherence (as measured) among testimonies implies a higher probability that the witnesses are reliable. Recently, it has been proved that several coherence measures proposed in the literature are reliability conducive in scenarios of equivalent testimonies (Olsson and Schubert 2007; Schubert, to appear). My aim is to investigate which coherence measures turn out to be reliability conducive in the more general scenario where the testimonies do not have to be equivalent. It is shown that four measures are reliability conducive in the present scenario, all of which are ordinally equivalent to the Shogenji measure. I take that to be an argument for the Shogenji measure being a fruitful explication of coherence.     

The defeasible nature of coherentist justification

The impossibility results of Bovens and Hartmann (2003, Bayesian epistemology. Oxford: Clarendon Press) and Olsson (2005, Against coherence: Truth, probability and justification. Oxford: Oxford University Press.) show that the link between coherence and probability is not as strong as some have supposed. This paper is an attempt to bring out a way in which coherence reasoning nevertheless can be justified, based on the idea that, even if it does not provide an infallible guide to probability, it can give us an indication thereof. It is further shown that this actually is the case, for several of the coherence measures discussed in the literature so far. We also discuss how this affects the possibility to use coherence as a means of epistemic justification.     

The Impossibility of Coherence

There is an emerging consensus in the literature on probabilistic coherence that such coherence cannot be truth conducive unless the information sources providing the cohering information are individually credible and collectively independent. Furthermore, coherence can at best be truth conducive in a ceteris paribus sense. Bovens and Hartmann have argued that there cannot be any measure of coherence that is truth conducive even in this very weak sense. In this paper, I give an alternative impossibility proof. I provide a relatively detailed comparison of the two results, which turn out to be logically unrelated, and argue that my result answers a question raised by Bovens and Hartmann’s study. Finally, I discuss the epistemological ramifications of these findings and try to make plausible that a shift to an explanatory framework such as Thagard’s is unlikely to turn the impossibility into a possibility.     

Coherence reasoning and reliability: a defense of the Shogenji measure

A measure of coherence is said to be reliability conducive if and only if a higher degree of coherence (as measured) results in a higher likelihood that the witnesses are reliable. Recently, it has been proved that several coherence measures proposed in the literature are reliability conducive in a restricted scenario (Olsson and Schubert 2007, Synthese 157:297?C308). My aim is to investigate which coherence measures turn out to be reliability conducive in the more general scenario where it is any finite number of witnesses that give equivalent reports. It is shown that only the so-called Shogenji measure is reliability conducive in this scenario. I take that to be an argument for the Shogenji measure being a fruitful explication of coherence.     

Is coherence conducive to reliability?

A measure of coherence is said to be reliability conducive if and only if a higher degree of coherence (as measured) of a set of testimonies implies a higher probability that the witnesses are reliable. Recently, it has been proved that the Shogenji measure of coherence is reliability conducive in restricted scenarios (e.g., Olsson and Schubert, Synthese, 157:297?C308, 2007). In this article, I investigate whether the Shogenji measure, or any other coherence measure, is reliability conducive in general. An impossibility theorem is proved to the effect that this is not the case. I conclude that coherence is not reliability conducive.     

A corrective to Bovens and Hartmann’s measure of coherence

Bovens and Hartmann (Bayesian Epistemology, Oxford: Oxford University Press, 2003) propose to analyze coherence as a confidence-boosting property. On the basis of this idea, they construct a new probabilistic theory of coherence. In this paper, I will attempt to show that the resulting measure of coherence clashes with some of the intuitions that motivate it. Also, I will try to show that this clash is not due to the view on coherence as a confidence-boosting property or to the general features of the model that Bovens and Hartmann use to analyze coherence. It will turn out that there is at least one other measure that is similarly based on the concept of a confidence-boosting property, but does not have the same counterintuitive results.     

EXPLAINING THE LIMITS OF OLSSON'S IMPOSSIBILITY RESULT

In his groundbreaking book, Against Coherence (2005), Erik Olsson presents an ingenious impossibility theorem that appears to show that there is no informative relationship between probabilistic measures of coherence and higher likelihood of truth. Although Olsson's result provides an important insight into probabilistic models of epistemological coherence, the scope of his negative result is more limited than generally appreciated. The key issue is the role conditional independence conditions play within the witness testimony model Olsson uses to establish his result. Olsson maintains that his witness model yields charitable ceteris paribus conditions for any theory of probabilistic coherence. Not so. In fact, Olsson's model, like Bayesian witness models in general, selects a peculiar class of models that are in no way representative of the range of options available to coherence theorists. Recent positive results suggest that there is a way to develop a formal theory of coherence after all. Further, although Bayesian witness models are not conducive to the truth, they are conducive to reliability.     

Inference to the best explanation: does it track truth?

In the form of inference known as inference to the best explanation there are various ways to characterise what is meant by the best explanation. This paper considers a number of such characterisations including several based on confirmation measures and several based on coherence measures. The goal is to find a measure which adequately captures what is meant by ‘best’ and which also yields the truth with a high degree of probability. Computer simulations are used to show that the overlap coherence measure achieves this goal, enabling the true explanation to be identified almost as often as an approach which simply selects the most probable explanation. Further advantages to this approach are also considered in the case where there is uncertainty in the prior probability distribution.     

A note on mathematical pluralism and logical pluralism

Mathematical pluralism notes that there are many different kinds of pure mathematical structures—notably those based on different logics—and that, qua pieces of pure mathematics, they are all equally good. Logical pluralism is the view that there are different logics (consequence relations), which are, in an appropriate sense, equally good. Some, such as Shapiro (Varieties of logic, Oxford University Press, Oxford, 2014), have argued that mathematical pluralism entails logical pluralism. In this brief note I argue that this does not follow. There is a crucial distinction to be drawn between the preservation of truth (simpliciter) and the preservation of truth-in-a-structure; and once this distinction is drawn, this suffices to block the argument. The paper starts by clarifying the relevant notions of mathematical and logical pluralism. It then explains why the argument from the first to the second does not follow. A final section considers a few objections.

     

Is Belief an Internal State?

This paper is a discussion of Michael Thau’s interesting critique in Chapter 2 of Consciousness and Cognition, Oxford: Oxford University Press, 2002, of the common view that beliefs are internal states.     

Personality and the coherence of psychotherapy narratives

The stories people construct about themselves and their social worlds are key aspects of their identities [Bruner, J. S. (1990). Acts of meaning. Cambridge, MA: Harvard University Press; McAdams, D. P. (2001). The psychology of life stories. Review of General Psychology, 5, 100–122]. Whereas certain expected life experiences (e.g., leaving home, getting a job) may be relatively easy to narrate, more unexpected and difficult events, such as undergoing psychotherapy, may pose a challenge to successful narration. Yet it is especially important to successfully narrate one’s experience in psychotherapy in order to maintain the gains from treatment [Frank, J. D. (1961). Persuasion and healing: A comprehensive study of psychotherapy. Baltimore, MD: Johns Hopkins University Press; Spence, D. P. (1982). Narrative truth and historical truth: Meaning and interpretation in psychoanalysis. New York: W.W. Norton]. The present study collected psychotherapy narratives from 76 adult former clients and coded them for the fundamental story criterion of coherence [Baerger, D. R., & McAdams, D. P. (1999). Life story coherence and its relation to psychological well-being. Narrative Inquiry, 9, 69–96]. Former clients that were high in trait Openness to experience and those at higher stages of ego development told more coherent stories about therapy. The relationship between ego development and narrative coherence remained significant even when controlling for Openness. The findings suggest that high ego development may provide narrators with the kind of sophisticated frameworks for meaning-making that are especially well-suited for the important task of making good sense of psychotherapy.     

Mechanism, Truth, and Penrose's New Argument

Sections 3.16 and 3.23 of Roger Penrose's Shadows of the mind (Oxford, Oxford University Press, 1994) contain a subtle and intriguing new argument against mechanism, the thesis that the human mind can be accurately modeled by a Turing machine. The argument, based on the incompleteness theorem, is designed to meet standard objections to the original Lucas–Penrose formulations. The new argument, however, seems to invoke an unrestricted truth predicate (and an unrestricted knowability predicate). If so, its premises are inconsistent. The usual ways of restricting the predicates either invalidate Penrose's reasoning or require presuppositions that the mechanist can reject.     

Free Will and Mental Powers

In this paper, we investigate how contemporary metaphysics of powers can further an understanding of agent-causal theories of free will. The recent upsurge of such ontologies of powers and the understanding of causation it affords promises to demystify the notion of an agent-causal power. However, as we argue pace (Mumford and Anjum in Analysis 74:20–25, 2013; Am Philos Q 52:1–12, 2015a), the very ubiquity of powers also poses a challenge to understanding in what sense exercises of an agent’s power to act could still be free—neither determined by external circumstances, nor random, but self-determined. To overcome this challenge, we must understand what distinguishes the power to act from ordinary powers. We suggest this difference lies in its rational nature, and argue that existing agent-causal accounts (e.g., O’Connor in Libertarian views: dualist and agent-causal theories, Oxford University Press, Oxford, 2002; Lowe in Personal agency: the metaphysics of mind and action, Oxford University Press, Oxford, 2013) fail to capture the sense in which the power to act is rational. A proper understanding, we argue, requires us to combine the recent idea that the power to act is a ‘two-way power’ (e.g., Steward in A metaphysics for freedom, Oxford University Press, Oxford, 2012b; Lowe (in: Groff, Greco (eds) Powers and capacities in philosophy: the new aristotelianism, Routledge, New York, 2013) with the idea that it is intrinsically rational. We sketch the outlines of an original account that promises to do this. On this picture, what distinguishes the power to act is its special generality—the power to act, unlike ordinary powers, does not come with any one typical manifestation. We argue that this special generality can be understood to be a feature of the capacity to reason. Thus, we argue, an account of agent-causation that can further our understanding of free will requires us to recognize a specifically rational or mental variety of power.

     

Primeness, Internalism and Explanatory Generality

Williamson (2000) [Knowledge and its Limits, Oxford: Oxford University Press] argues that attempts to substitute narrow mental states or narrow/environmental composites for broad and factive mental states will result in poorer explanations of behavior. I resist Williamson’s arguments and use Twin-Earth style cases to argue for the causal inertness of broad mental states.     

Comments on Sydney Shoemaker’s <Emphasis Type="Italic">Physical Realization</Emphasis>

This paper interprets and criticizes some of the views presented in Sydney Shoemaker’s book, Physical Realization (Oxford University Press, 2007), on the topic of how mental properties are realized by physical properties, given that, on his view, human persons are not even token-identical with human bodies.     

Non-monotonicity and Informal Reasoning: Comment on Ferguson (2003)

In this paper, it is argued that Ferguson’s (2003, Argumentation 17, 335–346) recent proposal to reconcile monotonic logic with defeasibility has three counterintuitive consequences. First, the conclusions that can be derived from his new rule of inference are vacuous, a point that as already made against default logics when there are conflicting defaults. Second, his proposal requires a procedural “hack” to the break the symmetry between the disjuncts of the tautological conclusions to which his proposal leads. Third, Ferguson’s proposal amounts to arguing that all everyday inferences are sound by definition. It is concluded that the informal logic response to defeasibility, that an account of the context in which inferences are sound or unsound is required, still stands. It is also observed that another possible response is given by Bayesian probability theory (Oaksford and Chater, in press, Bayesian Rationality: The Probabilistic Approach to Human Reasoning, Oxford University Press, Oxford, UK; Hahn and Oaksford, in press, Synthese).     

Against intentionalism

Intentionalism is the claim that the phenomenological properties of a perceptual experience supervene on its intentional properties. The paper presents a counter-example to this claim, one that concerns visual grouping phenomenology. I argue that this example is superior to superficially similar examples involving grouping phenomenology offered by Peacocke (Sense and Content, Oxford: Oxford University Press), because the standard intentionalist responses to Peacocke’s examples cannot be extended to mine. If Intentionalism fails, it is impossible to reduce the phenomenology of an experience to its content.     

Cosmic inflation and the past hypothesis

The past hypothesis is that the entropy of the universe was very low in the distant past. It is put forward to explain the entropic arrow of time but it has been suggested (e.g. [Penrose, R. (1989a). The emperor’s new mind. London:Vintage Books; Penrose, R. (1989b). Annals of the New York Academy of Sciences, 571, 249–264; Price, H. (1995). In S. F. Savitt (Ed.), Times’s arrows today. Cambridge: Cambridge University Press; Price, H. (1996). Time’s arrow and Archimedes’ point. Oxford: Oxford University Press; Price, H. (2004). In C. Hitchcock (Ed.), Contemporary debates in philosophy of science. Oxford: Blackwell]) that it is itself in need of explanation. It has also been suggested that cosmic inflation could provide the explanation, but Price (2004) raises a serious objection to this suggestion, which has otherwise received very little attention in the philosophical literature. Price points out that the standard inflationary explanation involves a double standard: although the evolution of the universe described by the inflationary model seems natural from the standard temporal perspective it looks highly unnatural from the reversed temporal perspective. The main purpose of this paper is to propose a novel form of the inflationary explanation that avoids this objection. It is argued that the inflationary model would not involve a double standard (but would still explain the past hypothesis) if we construct the model with a global “boundary” condition instead of a conventional boundary condition: if we assume that the universe is as generic as possible overall, rather than as generic as possible at some given point (e.g. the Big Bang) as is assumed in the standard inflationary model. This novel form of the inflationary explanation is then compared with Price’s 1996 preferred explanation, a version of the so-called “Weyl hypothesis”.     

Pleading ignorance in response to experiential primitivism

Modal arguments like the Knowledge Argument, the Conceivability Argument and the Inverted Spectrum Argument could be used to argue for experiential primitivism; the view that experiential truths aren’t entailed from nonexperiential truths. A way to resist these arguments is to follow Stoljar (Ignorance and imagination. Oxford University Press, Oxford, 2006) and plead ignorance of a type of experience-relevant nonexperiential truth. If we are ignorant of such a truth, we can’t imagine or conceive of the various sorts of scenarios that are required to make these arguments sound. While I am sympathetic to this response, in this article I will argue that we have good reason to believe that this particular ignorance hypothesis is false.     

Scanlon’s modal metaphysics

In Being Realistic About Reasons (Oxford University Press, 2014) T. M. Scanlon argues that particular fact about reasons are explained by contingent non-normative facts together with pure normative principles. A question then arises about the modal status of these pure principles. Scanlon maintains that they are necessary in a sense, and suggests that they are ‘metaphysically’ necessary. I argue that the best view for Scanlon to take, given his other commitments, is that these pure normative principles are metaphysically contingent in some cases and necessary only in a weaker sense.