Online research in philosophy

Practical Reasoning and Ethical Decision presents an account of practical reasoning as a process that can explain action, connect reasoning with intention, ...

This paper addresses an argument offered by John Hawthorne gainst the propriety of an agent’s using propositions she does not know as premises in practical reasoning. I will argue that there are a number of potential structural confounds in Hawthorne’s use of his main example, a case of practical reasoning about a lottery. By drawing these confounds out more explicitly, we can get a better sense of how to make appropriate use of such examples in theorizing about norms, knowledge, and practical reasoning. I will conclude by suggesting a prescription for properly using lottery propositions to do the sort of work that Hawthorne wants from them.

What is the relationship between logic and reasoning? How do logical norms guide inferential performance? This paper agrees with Gilbert Harman and most of the psychologists that logic is not directly relevant to reasoning. It argues, however, that the mental model theory of logical reasoning allows us to harmonise the basic principles of deductive reasoning and inferential perfomances, and that there is a strong connexion between our inferential norms and actual reasoning, along the lines of Peacocke’s conception of inferential role.

This paper seeks a better understanding of the elements of practical reasoning: premises and conclusion. It argues that the premises of practical reasoning do not normally include statements such as ‘I want to ϕ’; that the reasoning in practical reasoning is the same as in theoretical reasoning and that what makes it practical is, first, that the point of the relevant reasoning is given by the goal that the reasoner seeks to realize by means of that reasoning and the subsequent action; second, that the premises of such reasoning show the goodness of the action to be undertaken; third, that the conclusions of such reasoning may be actions or decisions, that can be accompanied by expressions of intention, either in action, or for the future; and that these are justified, and might be contradicted, in ways that are not only peculiar to them (i.e. in ways that diverge from those found in theoretical reasoning), but are distinctively practical, in that they involve reference to reasons for acting and to expressions of intention, respectively.1.

In this paper my primary aim is to present a logical system of practical reasoning that can be used to assess the validity of practical arguments, that is, arguments with a practical judgment as conclusion. I begin with a critical evaluation of other approaches to this issue and argue that they are inadequate. On the basis of these considerations, I explain in Sect. 2 the informal conception of practical validity and introduce in Sect. 3 the logical system P , which is an extension of propositional logic and can be used to assess the validity of a wide range of practical arguments. In the last section, I apply this system to some examples of practical reasoning in order to demonstrate how it can be used in practice.

I am currently examining the suggestion that assertion and practical reasoning are subject to specifically epistemic norms, and the consequences of this suggestion for the correct account of knowledge. One currently popular view is that knowledge is the epistemic norm of both assertion and practical reasoning (see DeRose, Hawthorne, Stanley and Williamson). If assertion and practical reasoning are governed by the knowledge norm, then one criterion for an account of knowledge is that it should respect the ties between knowledge, assertion and practical reasoning. In this way, the knowledge norm is at the heart of contemporary debate about the correct account of knowledge, e.g. the debate between contextualism and invariantism (see Hawthorne.

From its beginnings in Aristotle, logic was intended to account not only for reasoning that is theoretical (or conclusion-oriented), but for reasoning that is practical (or actionoriented). However, despite an interest in the topic that continues to the present, the practical side of reasoning has remained broadly speculative. At least in some domains (mathematics, in particular), there are well developed proof-theoretic and semantic theories that yield quite detailed models of correct reasoning, and these models are useful for both theoretical and practical purposes. In contrast, the logical work on practical reasoning has remained broadly speculative and disengaged from applications. Logical formalisms have not been forthcoming that would be useful either in designing an agent that needs to act intelligently, or in helping an intelligent agent to evaluate its reasoning about action.

In Knowledge and Lotteries, Hawthorne argues for a view on which whether a speaker knows that p depends on whether her practical environment makes it appropriate for her to use p in practical reasoning. It may seem that this view yields a straightforward account of why knowledge is important, based on the role of knowledge in practical reasoning. I argue that this is not so; practical reasoning does not motivate us to care about knowledge in itself. At best, practical reasoning motivates us to care about several other concepts in themselves, and ascriptions of knowledge provide economical summaries of these independently important desiderata.

One effect of information technology is the increasing need to present information visually. The trend raises intriguing questions. What is the logical status of reasoning that employs visualization? What are the cognitive advantages and pitfalls of this reasoning? What kinds of tools can be developed to aid in the use of visual representation? This newest volume on the Studies in Logic and Computation series addresses the logical aspects of the visualization of information. The authors of these specially commissioned papers explore the properties of diagrams, charts, and maps, and their use in problem solving and teaching basic reasoning skills. As computers make visual representations more commonplace, it is important for professionals, researchers and students in computer science, philosophy, and logic to develop an understanding of these tools; this book can clarify the relationship between visuals and information.