On David K. Lewis' Principal Principle and It's Inconsistency

The British Journal for the Philosophy of Science, 2017

In a recent paper in the British Journal for the Philosophy of Science, James Hawthorne, Jürgen Landes, Christian Wallmann, and Jon Williamson (henceforth HLWW) argue that the Principal Principle entails the Principle of Indifference. In this paper, I argue that it does not. Lewis’ version of the Principal Principle notoriously depends on a notion of admissibility, which Lewis uses to restrict its application. HLWW do not give a precise account either, but they do appeal to two principles concerning admissibility, which they call Condition 1 and Condition 2. There are two ways of reading their argument, depending on how you understand the status of Conditions 1 and 2. Reading 1: The correct account of admissibility is determined independently of these two principles, and yet these two principles follow from that correct account. Reading 2: The correct account of admissibility is determined in part by these two principles, so that the principles follow from that account but only because the correct account is constrained so that it must satisfy them. HLWW then show that, given an account of admissibility on which Conditions 1 and 2 hold, the Principal Principle entails the Principle of Indifference. I will argue that, on either reading of the argument, it fails. I will argue that there is a plausible account of admissibility on which Conditions 1 and 2 are false. That defeats the first reading of the argument. I will then argue that the intuitions that lead us to assent to Condition 2 also lead us to assent to other very closely related principles that are inconsistent with Condition 2. This, I claim, casts doubt on the reliability of those intuitions, and thus removes our justification for Condition 2. This defeats the second reading of the HLWW argument. Thus, the argument fails.

Hawthorne et al. (2015) argue that the Principal Principle implies a version of the Principle of Indifference. We show that what the Authors take to be the Principle of Indifference can be obtained without invoking anything which would seem to be related to the Principal Principle. In the Appendix we also discuss several Conditions proposed in the same paper.

We argue that David Lewis' Principal Principle implies a version of the Principle of Indifference. The same is true for similar principles which need to appeal to the concept of admissibility. Such principles are thus in accord with objective Bayesianism, but in tension with subjective Bayesianism. put forward the following principle as a constraint on a reasonable initial credence function P, which is taken to be a probability function:

2009

The theory of principles is multifaceted. Its initial expression contained an important argument against positivist theories of adjudication. As a legal theory, it fails in its effort to claim a structural difference between rules and principles. It also fails as a methodological theory that reduces adjudication to subsumption or balancing. It misunderstands itself when it is conceived as a doctrinal theory especially of fundamental rights. Its most promising aspect could be its contribution to a more comprehensive theory of legal argumentation.

Forthcoming in HOPOS, 2022

This volume represents the latest attempt to evaluate the philosophical legacy of C. I. Lewis's conceptual pragmatism, especially in the ambitious form found in his classic Mind and the World Order (MWO; 1929). While largely forgotten today, Lewis's contributions in formal logic (including its history), epistemology, and to a somewhat lesser degree moral philosophy had a profound influence on many philosophers, and the further critical engagement with his work fundamentally shaped the course of postwar American philosophy. However, his conceptual pragmatism is now often seen as an outdated epistemological framework plagued by the so-called three dogmas of empiricism and myth of the given made famous in the work of Quine, Sellars, and Davidson. 1 Few then see much point in looking back at the epistemological position defended in MWO. In response to this negative attitude, the stated aim of this new volume is to highlight both Lewis's historical importance and the ongoing contemporary relevance of his view (14-15), a claim also defended by other recent assessments. 2 There are a number of interesting issues discussed by the essays in this volume, including the role of logic in the development of Lewis's pragmatism, the status of his appeal to the empirical given, the connections between his mature epistemology and theory of value, and perhaps most importantly the fit between his pragmatism and somewhat more traditional form of empiricist epistemology. The essays do well in providing support for the historical significance of Lewis's achievements, but they also include criticisms that would seem to discredit its possible contemporary relevance. The following overview will then attempt to briefly sketch some of the ways these two themes are addressed by the essays.

European Journal of Pragmatism and American Philosophy, XIII-2, 2021

C. I. Lewis’s distinction between the given and the concept is often exposed as the key element of his treatment of the problem of intentionality in that the given and the concept would be necessary and sufficient conditions for objective purport. Such an account nonetheless offers a truncated picture of Lewis’s treatment of the problem of intentionality. The best way to appreciate this verdict is to state the predicament this account is confronted with: If the distinction between the given and the concept apparently leads to a version of the same problem it was designed to address, how could it be the key element contributing to answering the problem of intentionality? Indeed, according to Lewis, the given and the concept are mutually independent so that prima facie nothing guarantees that concepts are applicable to the given. The difficulty is what Lewis calls “the problem of the a priori”: how to guarantee that our concepts can be imposed upon a content of experience which is independent and not yet given? This is a version of the problem that Kant’s Transcendental Deduction addresses: How can categories, as subjective conditions of experience, be objectively valid? A natural question is then: How does Lewis address the problem of the a priori? The main purpose of this essay is then to investigate how C. I. Lewis’s addresses the problem of the a priori and to contribute to restoring an appropriate understanding of Lewis’s conceptual pragmatism. http://journals.openedition.org/ejpap/2573

The Monist, 2017

Kant saw science as presupposing that the natural laws bring maximal diversity under maximal unity. Many philosophers, such as David Lewis, have regarded objective chances as upshots of science's aim at systematic unity-as ideal credences projected onto the world. This Kantian projectivism has seemed the only possible way to account for the rational constraint (codified by the 'Principal Principle') that our credences about chances impose on our credences regarding what they are chances of. This paper examines three ways of elaborating Lewis's Kantian strategy for explaining this rational constraint. After arguing that none of these three approaches is unproblematic, the paper proposes a non-Kantian alternative account according to which a chance measures the strength of a causal tendency.

Erkenntnis, 2000

ExistencePS Press: https://epspress.com/NTF/VariousVersionsOfThePrinciple.pdf, 2020

The Principle of Plenitude has been underrated for understanding Aristotle's physics and metaphysics. The Northern Greek gives a specific formulation in PHYSICS III, "for eternal things, what may be, is," but Leibniz and Jonathan Barnes, Jaakko Hintikka and Sarah (Waterlow) Broadie and others have used different formulations, which typically leads to arguments at cross purposes. This article clarifies the different versions.