Robert Kowalski


Professor Emeritus and Senior Research Fellow

Department of Computing
Imperial College London


180 Queen's Gate, London SW7 2BZ, UK.

Email: rak at doc.ic.ac.uk

Please note that I am no longer accepting research students.


Entry in the International Directory of Logicians

"International Directory of Logicians" , Dov M. Gabbay & John Woods (eds.) College Publications 2008.


Curriculum Vitae


A Short Story of My Life and Work


Computational Logic and Human Thinking:
How to be Artificially Intelligent

This book, published in July 2011 by Cambridge University Press, presents the principles of Computational Logic, so that they can be applied by people in everyday life.  I have written the main part of the book informally, both to reach a wider audience and to demonstrate that the enhanced logic is indeed useful for human thinking. However, I have also included a number of additional, more formal chapters for the more advanced reader.

I have given a short course based on the book at the Third International ALP/GULP Spring School on Computational Logic in Bertinoro, Italy, 10-15 April 2011. Here is a link to the slides.

Jacinto Davila has also used a draft of this book for a course at Universidad de Los Andes, Venezuela. Here is a link to his Spanish translation of an earlier draft: http://webdelprofesor.ula.ve/ingenieria/jacinto/kowalski/logica-de-agentes.html


Logic for Problem Solving

The book, originally published by North-Holland in 1979, is now out of print.


New paper: Teleo-Reactive Abductive Logic Programs with Fariba Sadri

Teleo-reactive (TR) programs are a variety of production systems with a destructively updated database that represents the current state of the environment. They combine proactive behaviour, which is goal-oriented, with reactive behaviour, which is sensitive to the changing environment. They can take advantage of situations in which the environment opportunistically solves the system’s goals, recover gracefully when the environment destroys solutions of its goals, and abort durative actions when higher priority goals need more urgent attention.

In this paper, we present an abductive logic programming (ALP) representation of TR programs, following the example of our ALP representation of the logic-based production system language LPS. The operational semantics of the representation employs a destructively updated database, which represents the current state of the environment, and avoids the frame problem of explicitly reasoning about the persistence of facts that are not affected by the updates. The model-theoretic semantics of the representation is defined by associating a logic program with the TR program, the sequence of observations and actions, and the succession of database states. In the semantics, the task is to generate actions so that all of the program’s goals are true in a minimal model of this associated logic program.


Time to Think Like a Computer (not my title)  New Scientist 3 December 2011

"For years, philosophers, linguists, and psychologists have puzzled over the relationship between human language and thought. Now, says Robert Kowalski, in the quest to create artificial intelligence in machines, researchers have come up with some unexpected answers."


New paper: WUENIC – A Case Study in Rule-based Knowledge Representation and Reasoning with Anthony Burton. Presented at JURISIN 2011

WUENIC is a rule-based system implemented as a logic program, developed by WHO and UNICEF for estimating global, country by country, infant immunization coverage. It possesses many of the characteristics of rule-based legislation, facilitating decisions that are consistent, transparent and replicable. In this paper, we focus on knowledge representation and problem-solving issues, including the use of logical rules versus production rules, backward versus forward reasoning, and rules and exceptions versus argumentation

Here is an associated tutorial WUENIC: a logic-based representation of the WHO and UNICEF estimates of national immunization coverage.


Recent Paper: Artificial Intelligence and Human Thinking  Presented at IJCAI 2011

Research in AI has built upon the tools and techniques of many different disciplines, including formal logic, probability theory, decision theory, management science, linguistics and philosophy. However, the application of these disciplines in AI has necessitated the development of many enhancements and extensions. Among the most powerful of these are the methods of computational logic.
       I argue that computational logic, embedded in an agent cycle, combines and improves upon both traditional logic and classical decision theory. I will also argue that many of its methods can be used, not only in AI, but also in ordinary life, to help people improve their own human intelligence without the assistance of computers.


Recent paper: Abductive Logic Programming Agents with Destructive Databases   with Fariba Sadri

To appear in Annals of Mathematics and Artificial Intelligence. This is an extended version of An Agent Language with Destructive Assignment and Model-theoretic Semantics, which appeared In CLIMA XI - Computational Logic in Multi- Agent Systems (eds. J. Dix, G. Governatori, W. Jamroga and J. Leite) Springer, 2010.

In this paper we present an agent language that combines agent functionality with an action theory and model-theoretic semantics. The language is based on abductive logic programming (ALP), but employs a simplified state-free syntax, with an operational semantics that uses destructive assignment to manipulate a database, which represents the current state of the environment. The language builds upon the ALP combination of logic programs, to represent an agent’s beliefs, and integrity constraints, to represent the agent’s goals. Logic programs are used to define macro-actions, intensional predicates, and plans to reduce goals to sub-goals including actions. Integrity constraints are used to represent reactive rules, which are triggered by the current state of the database and recent agent actions and external events. The execution of actions and the assimilation of observations generate a sequence of database states. In the case of the successful solution of all goals, this sequence, taken as a whole, determines a model that makes the agent’s goals and beliefs all true.


Selected bibliography

Early papers on theorem-proving, logic programming and knowledge representation:

Legal reasoning and argumentation

Metalogic programming

Event Calculus

Abductive Logic Programming 

From Abduction to Argumentation

Intelligent Agents

   Miscellaneous papers

Updated 1 February 2012