Why Aquinas Would Agree That Human Economic Behaviour Is Largely Predictable

Many people, from retailers and advertisers to the Chancellor of the Exchequer, work on the assumption that human economic behaviour is to a fair degree predictable, at least statistically. This paper asks how far the thirteenth-century Thomas Aquinas would agree that human behaviour (including economic behaviour) is predictable, both the behaviour of individuals and the behaviour of groups, and on what grounds. In doing so it also asks how any elements of predictability would square with Aquinas’ conviction that human beings enjoy liberum arbitrium, “free decision”. In the context of the present volume, exploring Aquinas’ position may promote a nuanced and multivalent approach to the question of what causes human behaviour, and liberate us from the fear that if human behaviour is caused, it cannot be free.