External validity and libraries of phenomena:a critique of Guala's methodology of experimental economics

Francesco Guala has developed some novel and radical ideas on the problem of external validity, a topic that has not received much attention in the experimental economics literature. In this paper I argue that his views on external validity are not justified and the conclusions which he draws from these views, if widely adopted, could substantially undermine the experimental economics enterprise. In rejecting the justification of these views, the paper reaffirms the importance of experiments in economics