Professor David Clement Makinson is currently Visiting Professor in the Department of Philosophy, Logic and Scientific Method, London School of Economics (LSE). He has been a Senior Research Fellow  in the Department of Computer Science, King’s College London, Chairman of the Department in the American University of Beirut, Lebanon, and Programme Specialist with Unesco.

                                         In Beijing 2006

 His field of research is Logic and its relations with other disciplines, particularly philosophy and computer science. His most recent research has been on: 

• Uncertain reasoning: qualitative and quantitative and their interconnections
• Parallel interpolation and its application
• Relevance criteria for belief change operations
• Input/output logics, logics of directives and norms
• The concept of logical friendliness

Principal Research Achievements 

Reference numbers are to the list of publications

Logic of Belief Change

Perhaps my most frequently cited work is the creation of the so-called AGM account of the logic of belief change, with Carlos Alchourrón and Peter Gärdenfors. This was done in a variety of converging forms: postulational, in terms of partial meet operations, relations of epistemic entrenchment, and safe contraction (1980s esp. refs 20, 23, 24, 25, 26), with also a paper (54) reviewing the ways in which the logic of belief change and nonmonotonic logic has led to new ways of doing logic. Recent papers examine the question of relevance in belief change, in the light of the finest splitting theorem (refs 64, 65 with George Kourousias, 67). 

Logic of Uncertain Reasoning

In the area of the qualitative analysis of uncertain reasoning, commonly (and rather misleadingly) known as nonmonotonic logic,  my research has followed three main lines. One was directed to clarifying the logical patterns to be found in nonmonotonic inference  contribution (1989 ref 31, 1994 ref 42). Another, carried out jointly with Peter Gärdenfors in the same period, established the basic relationships between nonmonotonic inference and belief revision (1980s refs 35, 40). More recently (refs 53, 58, 60, 66, B3), my investigations focussed on examining bridge systems between classical and nonmomotonic logics. Current publications in this area examine the relations between qualitative and probabilistic approaches to uncertain reasoning (ref 63, with James Hawthorne), the concept of a lossy inference rule (ref 69) and conditional probability in the light of qualitative belief change (ref 68).  

Logic of Norms and Normative Systems

In the logic of norms (also known as deontic logic), my best-known publications (1980s items 27 and 30) analyse the Hohfeld classification of rights relationships and its application to real-life rights claims (particularly collective rights), reconstruct of the logic of norms in accord with the philosophical position that norms lack truth values (1999 ref 50). More recent work centred on elaborating a general theory of input/output logics as a framework for conditional directives and permissions (refs 51, 52, 54, 56).

Early Work in Modal Logic

Early work focussed largely on modal logic. Perhaps the most cited contribution in this area was the adaptation, in my1965 D.Phil. thesis and a following publication (1966 ref 6), of the maximal consistent set method, then well-known in classical propositional and predicate logic (Lindenbaum, Henkin), to serve as a tool for establishing completeness results in modal and other non-classical logics, where it is now a standard procedure. Also often mentioned is the discovery (1969 ref 8) of the first simple and natural propositional logic lacking the finite model property; and formulation (1970 ref 10) of a generalised notion of relational model for modal logic, bringing the relational account into harmony with the algebraic one. Another, quite ignored at the time of its publication in 1971 but much cited in recent years (ref 12), gives the first and still the main embedding theorems for modal logics. 

Other Areas of Logic

Some of my research output does not fall squarely into any of the above categories. One paper (ref 43) in the theory of preference aggregation, separates combinatorial from decision-theoretic components in Arrow's impossibility theorem and the closely related Blair/Bordes/Kelly/Suzumura theorem in the theory of collective preference, providing a particularly elegant proof of those results. Another (ref 61) introduces the fascinating concept of logical friendliness, and studies its manifestations in the literature of the last hundred and fifty years, as well as its properties. A third introduces the concept of parallel interpolation, and continues Parikh's analysis of splitting in classical propositional logic (refs 64, 65, with George Kourousias, also 67) . Most recently, paper (ref 70) in press undertakes a close examination of intuitionistic logic and the notion of an elementary rule for sequents, and another (ref 71), in preparation, studies the relationship between classical and relevance logic.