Reasoning and Evidence One Does Not Possess1

Minds and Machines - MIND MACH, 1997

I articulate a functional characterisation of the concept of evidence, according to which evidence is that which allows us to make inferences that extend our knowledge. This entails Williamson's equation of knowledge with evidence.

Philosophy for MATSEC, 2021

Module 1 of the MATSEC Intermediate and Advanced Philosophy Syllabi (EQF 4)

Argumentation, 2020

Logic and logical philosophy

The last century has seen many disciplines place a greater priority on understanding how people reason in a particular domain, and several illuminating theories of informal logic and argumentation have been developed. Perhaps owing to their diverse backgrounds, there are several connections and overlapping ideas between the theories, which appear to have been overlooked. We focus on Peirce’s development of abductive reasoning [Peirce, 1931-58], Toulmin’s argumentation layout [Toulmin, 1958], Lakatos’s theory of reasoning in mathematics [Lakatos, 1976], Pollock’s notions of counterexample [Pollock, 1995], and argumentation schemes constructed by Walton et al. [Walton, 2008], and explore some connections between, as well as within, the theories. For instance, we investigate Peirce’s abduction to deal with surprising situations in mathematics, represent Pollock’s examples in terms of Toulmin’s layout, discuss connections between Toulmin’s layout and Walton’s argumentation schemes, and suggest new argumentation schemes to cover the sort of reasoning that Lakatos describes, in which arguments may be accepted as faulty, but revised, rather than being accepted or rejected. We also consider how such theories may apply to reasoning in mathematics: in particular, we aim to build on ideas such as Dove’s [Dove, 2007], which help to show ways in which the work of Lakatos fits into the informal reasoning community.

2007

Some of the few who endorse some such requirement are Fumerton [1995], Bonjour [1998], Wright [2004a]-but not without qualification. 2 For instance Van Cleve [1984], Greco [1999]. 1 This proposition is, at least at the face of it, not equivalent to the proposition (1) and (2) epistemically support (3). The latter proposition is about an epistemic supportrelation, not about a logical relation. But I think that some of the things said in this chapter about L apply to the latter proposition too. But there are very important differences between the two [cf. Cohen, 1998], so that they must be properly treated separately. I discuss similar issues with respect to the proposition about epistemic support in chapter 4. 2 "equivocation" may be understood as designating the fact that the same linguistic expression in two different premises stands for two different concepts. In this sense the mental process of inferring cannot show "equivocation". But whenever we fall prey to an "equivocation", it is also true that our reasoning is defective. It is this defect in reasoning that I call equivocation. 3 I discuss the relation between evidence and attitudes in section 2.2. 4 I sometimes express this fact by saying that the subject "has justification for (3)" or that for the subject "(3) has positive epistemic status". 5 I express the fact that the subject believes (3) for her good epistemic reason sometimes by saying that she "justifiably believes (3)" or that she "is justified in believing (3)". Furthermore, the subject's believing (3) for her good epistemic reason in N , involves the fact that I express by saying that the subject "bases her belief in (3) on her beliefs in (1) and (2)". See below in the text. 12 Furthermore Fumerton does not distinguish between E makes probable P and E supports/justifies P. In his commentary to Fumerton [1995], Stewart Cohen [1998] objects to taking the latter two propositions to be equivalent.

Synthese

This paper develops a novel, functionalist, unified account of the epistemic normativity of reasoning. On this view, epistemic norms drop out of epistemic functions. I argue that practical reasoning serves a prudential function of generating prudentially permissible action, and the epistemic function of generating knowledge of what one ought to do. This picture, if right, goes a long way towards normatively divorcing action and practical reasoning. At the same time, it unifies reasoning epistemically: practical and theoretical reasoning will turn out to be governed by the same epistemic norm—knowledge—in virtue of serving the same epistemic function: generating knowledge of the conclusion.

Timothy Williamson has argued that one proposition e can serve as evidence for a hypothesis h for a subject s under two conditions. The first condition is that the proposition e must be known, and the second condition is that the probability of h on e must be greater than the probability of h alone. It is my purpose to challenge this first constraint on evidence ((E=K) for now). In section one, I argue by counterexample that (E=K) forces an implausible separation between what it means for a belief to be rational, justified, and properly guided in its formation on the one hand, and evidentially supported on the other. These arguments are similar in spirit to arguments that evidentialists and other epistemic internalists have used against reliabilist views of justification.