In September 2009, the ‘Practice-based philosophy of logic and mathematics’ workshop (http://www.illc.uva.nl/pplm) took place in Amsterdam, with the aim of discussing the prospects for the formulation of a philosophical approach to logic (and mathematics) which would take the actual practices of logicians and mathematicians into account. The event was very successful, but it also became clear that a practice-based approach could be pursued in different ways and on different levels: an individual-cognitive level; a social level; a historical level (to name but a few).
Giving continuation to a practice-based approach to the philosophy of logic, but this time seeking to narrow down its scope to a more specific theme, we are now organizing this workshop on the interface between cognitive science and psychology, on the one hand, and the philosophy of logic on the other hand. More specifically, we wish to investigate the extent to which (if at all), and in which ways, experimental results from these fields may contribute to the formulation of an empirically-informed philosophy of logic, one that takes into account how human agents, logicians and non-logicians alike, in fact reason. After all, ‘logic is the art and science of correct reasoning’ is one of the most-often repeated slogans when a definition of logic is called for, so the connection between logic and human reasoning cannot be overlooked (even if ultimately to be contested). The goal is to shed new light on logic as a human enterprise, as an activity undertaken by humans, by incorporating empirical findings on (predominantly human) cognition into the analysis. Some of the questions and issues to be discussed are:
- Similarities and discrepancies between the precepts of logical reasoning and everyday-life forms of reasoning. Given the observation that subjects typically do not do well in experiments with deductive reasoning tasks (that is, if measured against the traditional canons of logic and deduction), what does this tell us about logic as an enterprise and about the role of logic in human cognition generally speaking?
- Given these discrepancies, what are the prospects for a psychologistic account of logic? After almost a century of predominance of anti-psychologism in logic (since Frege’s influential criticism), recent years have witnessed a resurgence of psychologistic accounts of logic, in particular against the background of the recent popularity of naturalism in philosophy. But now psychologistic accounts of logic seem to stumble upon lack of empirical corroboration; or is it possible to interpret these results in ways that are compatible with psychologism in logic? If they are not compatible with empirical data, such accounts may well be no more than 'just-so stories'.
- Perhaps logic as traditionally construed is indeed not to be found in human cognition; but there might be another ‘logic’ underlying human cognition. In particular, common-sense reasoning appears to be essentially non-monotonic, whereas classical logic is monotonic. If that is the case, is this a reason for us to rethink our very conception of logic? Is logic indeed the ‘art and science of correct reasoning’, or is it not about reasoning at all, as some maintain? But in the latter case, what is it about then?
- What can the similarities and dissimilarities between human cognition and the cognition of non-human animals (as experimentally observed) tell us about logic and its place in cognition?
- If logic is fundamentally a normative enterprise (dealing with correct patterns of reasoning), how can attention to actual patterns of human reasoning contribute to a better understanding of the enterprise as a whole? More generally, logic is often thought to deal with purely aprioristic matters: is ‘empirically-informed philosophy of logic’ an oxymoron, or is it an enterprise worth pursuing? What about the is/ought divide?
- What (if anything) can results from cognitive sciences and psychology tell us about how professional logicians operate on a cognitive level? Even if one maintains the view that logic is not naturally or universally present in human cognition, logic as a discipline is obviously practiced by human agents having (roughly) the same cognitive apparatus. What new insights can we gain on such practices by bringing in experimental results?
