Representation Languages and (Anti)Reductionist Perspectives Catholijn M. Jonker1 and Jan Treur2 1 Radboud Universiteit Nijmegen, Nijmegen Institute of Cognition and Information, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands Email: C.Jonker@nici.ru.nl URL: http://www.nici.ru.nl/~catholj 2 Vrije Universiteit Amsterdam, Department of Artificial Intelligence De Boelelaan 1081a, 1081 HV Amsterdam, The Netherlands Email: treur@cs.vu.nl URL: http://www.cs.vu.nl/~treur Abstract In the philosophical literature on reduction of scientific theories, it is implicitly assumed that the advantages of reduction are based on the elimination of the higher-level theory. Antireductionist researchers and philosophers, defending an autonomous status for higher-level theories in the special sciences such as Biology and Cognitive Science, use as a main strategy to cast doubt on the existence of reduction relations between higher-level and lower-level theories. From our point of view this is a debatable strategy. Scientific progress made in areas such as Biochemistry and Neuroscience makes it more difficult to persist on the view that reduction relations do not exist. The alternative strategy put forward in this paper accepts the existence of reduction relations, but claims that this can perfectly well go hand in hand with and even supports an antireductionist view on the development of higher-level theories. To support our position, as a case study, we consider the historical development of representation languages at different levels of abstraction within Computer Science and Artificial Intelligence. This case study shows how reduction relations between higher-level and lower-level languages support the human in practice. A practitioner can concentrate work at a higher-level of abstraction, while within the computer, hidden for the human, automated translations to lower levels are made based on reduction relations. In this paper reduction and its pragmatics are discussed in light of the development in Computer Science and Artifical Intelligence of representation languages at different levels of abstraction. The design of higher-level modelling languages has had the aim of allowing for description of the world on a higher level avoiding (physical) details. The higher description levels developed have dramatically increased the complexity of applications that came within reach and the speed with which such applications are developed. The pragmatic attitude of a (scientific) practitioner in this area has become inherently anti-reductionist, but based on well-established reduction relations. The paper discusses how this perspective can be related to reduction in general. Keywords computer languages, reduction, antireductionist perspective, philosophy of mind, cognitive science 1