A Map of Common Knowledge Logics

In order to capture the concept of common knowledge, various extensions of multi-modal epistemic logics, such as fixed-point ones and infinitary ones, have been proposed. Although we have now a good list of such proposed extensions, the relationships among them are still unclear. The purpose of this paper is to draw a map showing the relationships among them. In the propositional case, these extensions turn out to be all Kripke complete and can be comparable in a meaningful manner. F. Wolter showed that the predicate extension of the Halpern-Moses fixed-point type common knowledge logic is Kripke incomplete. However, if we go further to an infinitary extension, Kripke completeness would be recovered. Thus there is some gap in the predicate case. In drawing the map, we focus on what is happening around the gap in the predicate case. The map enables us to better understand the common knowledge logics as a whole.     

Being German,Paraguayan and Germanino: Exploring the Relation Between Social and Personal Identity

Despite people’s claims, their national, ethnic and other identities are not ubiquitously relevant, they are rather situationally evoked and performed. Such is the case with the German, Paraguayan and Germanino identity in the municipality of Nueva Germania, in Paraguay. Recognising such contextual epistemic permissibility allows us to form a de-essentialised understanding of groups and individuals. One of the challenges that emerge from this approach, is to understand how a person can perform different identities, which differently define who they are, while remaining certain of being a continuous and persistent person. The objective of this article is to provide a theoretical grounding for theories of social identity in theories of personal identity. It allows us to analytically accommodate the situational and multiscalar character of identities, while recognising their existential importance for personal identity (for the Self).     

Once More Unto the Breach: Type B Physicalism,Phenomenal Concepts,and the Epistemic Gap

Type B, or a posteriori, physicalism is the view that phenomenal-physical identity statements can be necessarily true, even though they cannot be known a priori—and that the key to understanding their status is to understand the special features of our phenomenal concepts, those concepts of our experiential states acquired through introspection. This view was once regarded as a promising response to anti-physicalist arguments that maintain that an epistemic gap between phenomenal and physical concepts entails that phenomenal and physical properties are distinct. More recently, however, many physicalists have lost confidence in the view, and have proposed less promising defences of physicalism—or have become outright sceptical about its prospects. I argue here that these physicalists have underestimated the resources of Type B physicalism and are thereby retreating too quickly—or fighting battles that have already been won.     

Explaining Evidence Denial as Motivated Pragmatically Rational Epistemic Irrationality

This paper introduces a model for evidence denial that explains this behavior as a manifestation of rationality, and it is based on the contention that social values (measurable as utilities) often underwrite these sorts of responses. Moreover, it contends that the value associated with group membership in particular can override epistemic reason when the expected utility of a belief or belief system is great. It is also true, however, that it appears to be the case that it is still possible for such unreasonable believers to reverse this sort of dogmatism and to change their beliefs in a way that is epistemically rational. The conjecture made here is that we should expect this to happen only when the expected utility of the beliefs in question dips below a threshold where the utility value of continued dogmatism and the associated group membership is no longer sufficient to motivate defusing the counterevidence that tells against such epistemically irrational beliefs.     

Normativity in the Philosophy of Science

This paper analyzes what it means for philosophy of science to be normative. It argues that normativity is a multifaceted phenomenon rather than a general feature that a philosophical theory either has or lacks. It analyzes the normativity of philosophy of science by articulating three ways in which a philosophical theory can be normative. Methodological normativity arises from normative assumptions that philosophers make when they select, interpret, evaluate, and mutually adjust relevant empirical information, on which they base their philosophical theories. Object normativity emerges from the fact that the object of philosophical theorizing can itself be normative, such as when philosophers discuss epistemic norms in science. Metanormativity arises from the kind of claims that a philosophical theory contains, such as normative claims about science as it should be. Distinguishing these three kinds of normativity gives rise to a nuanced and illuminating view of how philosophy of science can be normative.     

REPLY TO JULIA DRIVER,TIMM TRIPLETT,AND KATHLEEN WALLACE

Abstract: Julia Driver, Timm Triplett, and Kathleen Wallace challenge my account of moral arrogance, and Triplett and Wallace challenge its application to the problem of abortion. I try to show here that Driver's attempt to defend consequentialism from my charge that it promotes moral arrogance is successful only if consequentialism explicitly gives up what has been considered one of its major virtues. I acknowledge that Triplett has uncovered some unclarity in my claim that the moral acceptability of abortion is an unresolvable moral issue. I also acknowledge that Wallace has uncovered some unclarity in my account of moral arrogance. After clarifying that account, I try to meet her challenge to defend my claim that it is not morally arrogant for a state to place some restrictions on abortions.     

Rules for Reasoning from Knowledge and Lack of Knowledge

In this paper, the traditional view that argumentum ad ignorantiam is a logical fallacy is challenged, and lessons are drawn on how to model inferences drawn from knowledge in combination with ones drawn from lack of knowledge. Five defeasible rules for evaluating knowledge-based arguments that apply to inferences drawn under conditions of lack of knowledge are formulated. They are the veridicality rule, the consistency of knowledge rule, the closure of knowledge rule, the rule of refutation and the rule for argument from ignorance. The basic thesis of the paper is that knowledge-based arguments, including the argument from ignorance, need to be evaluated by criteria for epistemic closure and other evidential rules that are pragmatic in nature, that need to be formulated and applied differently at different stages of an investigation or discussion. The paper helps us to understand practical criteria that should be used to evaluate all arguments based on knowledge and/or ignorance.

On Łukasiewicz's Four-Valued Modal Logic

ukasiewicz's four-valued modal logic is surveyed and analyzed, together with ukasiewicz's motivations to develop it. A faithful interpretation of it in classical (non-modal) two-valued logic is presented, and some consequences are drawn concerning its classification and its algebraic behaviour. Some counter-intuitive aspects of this logic are discussed in the light of the presented results, ukasiewicz's own texts, and related literature.     

Meno and the Monist

Recent critiques of veritistic value monism, or the idea that true belief is unique in being of fundamental epistemic value, typically invoke a claim about the surplus value of knowledge over mere true belief, in turn traced back to Plato's Meno. However, to the extent Plato at all defends a surplus claim in the Meno, it differs from that figuring in contemporary discussions with respect to both its scope and the kind of value at issue, and is under closer scrutiny fully compatible with veritistic value monism. Consequently, contrary to what seems to be supposed in the literature, the critics of monism have little to gain from turning to the Meno for support.