Ad Hoc Hypotheses and the Monsters Within

  • Ioannis VotsisEmail author
Part of the Synthese Library book series (SYLI, volume 376)


Science is increasingly becoming automated. Tasks yet to be fully automated include the conjecturing, modifying, extending and testing of hypotheses. At present scientists have an array of methods to help them carry out those tasks. These range from the well-articulated, formal and unexceptional rules to the semi-articulated and variously understood rules-of-thumb and intuitive hunches. If we are to hand over at least some of the aforementioned tasks to machines, we need to clarify, refine and make formal, not to mention computable, even the more obscure of the methods scientists successfully employ in their inquiries. The focus of this essay is one such less-than-transparent methodological rule. I am here referring to the rule that ad hoc hypotheses ought to be spurned. This essay begins with a brief examination of some notable conceptions of ad hoc-ness in the philosophical literature. It is pointed out that there is a general problem afflicting most such conceptions, namely the intuitive judgments that are supposed to motivate them are not universally shared. Instead of getting bogged down in what ad hoc-ness exactly means, I shift the focus of the analysis to one undesirable feature often present in alleged cases of ad hoc-ness. I call this feature the ‘monstrousness’ of a hypothesis. A fully articulated formal account of this feature is presented by specifying what it is about the internal constitution of a hypothesis that makes it monstrous. Using this account, a monstrousness measure is then proposed and somewhat sketchily compared with the minimum description length approach.


Ad hoc Scientific methodology Minimum description length Philosophy of artificial intelligence Computational science 



My sincerest thanks to three anonymous referees as well as to my colleagues, Gerhard Schurz and Paul Thorn, for valuable feedback on the material presented in this essay. I acknowledge the German Research Foundation (Deutsche Forschungsgemeinschaft) for funding my research under project B4 of Collaborative Research Centre 991: The Structure of Representations in Language, Cognition, and Science. Part of this essay has been written while working on the project ‘Aspects and Prospects of Realism in the Philosophy of Science and Mathematics’ (APRePoSMa) during a visiting fellowship at the University of Athens. The project and my visits are co-financed by the European Union (European Social Fund—ESF) and Greek national funds through the Operational Program ‘Education and Lifelong Learning’ of the National Strategic Reference Framework (NSRF)—Research Funding Program: THALIS—UOA.


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© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.New College of the HumanitiesLondonUK

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