Quetelet sought to take further the application of probability theory to quantitative social data. Using the Gaussian error curve – or normal distribution -- he undertook analyses, based on the concept of average types of men and women, that went beyond regularities in simply ‘events’, such as deaths, to those that he believed were demonstrable in ‘volitional phenomena’ such as suicide, crime and marriage. These he recognised as examples of the basic explananda of sociological science. He grappled with problems of the identification of the causal factors underlying such regularities and of the creation of variables that adequately reflected population heterogeneity. Although achieving no great success in these respects, being in various ways too far ahead of his times, he did highlight problems of a fundamental kind and signposted the directions in which advances had to be made. The reception of his work in France, Germany and Britain pointed to a range of major issues that lay ahead.