My Research 

Research Interests

Three primary areas of interest are the concept of logical consequence, the relationship between metaphysics and logic, and the epistemic status of logical truths (or of claims about the extension of logical consequence). Much of my published work (and my dissertation) centers around the question:  What is logical consequence?  (or what distinguishes a logical truth from other kinds of truth?)  One aspect of this issue that particularly interests me is the nature and extent of the metaphyiscal assumptions required to give an adequate semantic characterization of logical consequence.

I am also interested  in  20th C. analytic philosophy and the prescribed role logic is assigned to play in philosophy.  Do we want logic to be a philosophically neutral language in which all metaphysical theories can be formulated?  This seems to have been Leibniz’s idea of a “characteristica universalis.”  Or do we expect logic to make metaphysical problems obsolete?  Russell, Wittgenstein, and the Vienna Circle all wished for this, and much of their logical work was motivated by eliminating metaphysical commitments from logical analysis (e.g., Russell’s “On Denoting”).  This, of course, has been the traditional analytic attitude.  I think that this misconstrues the nature of logic, since  I believe that metaphysics is in a significant sense prior to logic.
 


Recent Research

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Article length projects

 Truth Simpliciter and Logical Consequence.   According to a truth simpliciter account of logical consequence, the conclusion of an argument is a logical consequence of its premises, i.e., the argument is valid, just in case truth is preserved from the premise(s) to the conclusion, the world remaining as it is.  Definitive of such accounts, which do differ, is that logical consequence is explained by appealing to truth simpliciter, i.e., truth in the actual world, rather than to truth in possible worlds that represent alternative ways the world might have turned out.  In this paper, I defend the appeal to truth simpliciter by responding to two recent criticisms. The first criticism, due to William Hanson, claims that no truth simpliciter account is extensionally correct in first-order logic with identity.  The second criticism, derived mainly from John Etchemendy, is that a truth simpliciter account is intensionally incorrect because it fails to reflect the modal and epistemic features of the intuitive concept of logical consequence.  In this paper, I argue that the first criticism is false and that it misrepresents the nature of a truth simpliciter account of logical consequence.  With respect to the second criticism, I shall argue that it fails to offer a plausible clarification of the modal feature of logical consequence which shows that it cannot be captured by a truth simpliciter account.  Also, I shall argue that the second criticism fails because it misconceives the epistemic feature of the concept of logical consequence.  I don’t see why a truth simpliciter account misrepresents this feature, properly understood.
 
 

A Defense of the Kripkean Account of Logical Truth in First-Order Modal Logic.   This paper is forthcoming in the Journal of Philosophical Logic.  It is concerned with the criticism of the Kripkean representation of logical truth in first-order modal logic as truth at the actual world of every subset of the set of possible worlds.  The point of contention is the variability of the collection of possible worlds from one model structure to another in fixing the extension of logical truth for a first-order modal language.  For particular readings of the modal operators, this feature has been called curious, completely lacking in motivation, and the cause of the Kripke account missing some logical truths.  The criticism has been largely ignored.  The primary goal of this paper is to establish the relevance of the possible situations represented by variations in the set of possible worlds to the determination of logical truth in first-order modal logic.
 

Logic and Existential Commitment is a paper that is forthcoming in Logique et Analyse.  Here I challenge the idea the logic is free from existential commitment.  Divorcing the foundations of logic from ontology is plagued with substantial epistemological difficulties, and at present the advantages of doing this are unclear.  I conclude by highlighting why this should increase the comfort level for thinking that ordinary first-order logic depends on substantive facts about the world.

Focusing on Russell's early view of the nature of logic, in, Russell and Logical Ontology, I  attempt to  motivate a return to the pre-Wittgensteinian notion of a distinctly logical ontology that is in  Russell's pre-1908 account of logic.
 

 I devoted much of my fall 2004 reserach leave to Unrestricted Quantification and Identity. This is a new area of research for me.  Motivated by Quine's remark that objectual quantification appeals to a notion of identity, I initially set out to discover  why this might be true and wanted to offer a rationale for Quine's remark  (something Quine does not clearly do) derived from Quine's work.  I now think that  objectual quantification does require a notion of strict identity and that this requirement rules out the viability of unrestricted quantification, at least construed objectually.
 

Book length Project

Philosophy of Logical Consequence is geared towards advanced undergraduate and graduate students, and interested non-specialists.  It is a rigorous introduction to the concept of logical consequence.
 

Comments?  You can e-mail me at:  mckeonm@msu.edu