This course aims to introduce students to scientific reasoning within natural and social sciences from their origins. We will then study the problem of scientificity and objectivity of natural and social sciences, and the problem of social sciences’ unit research analysis (the debate around individual versus society). The course will then focuses on some among the main approaches to the explanation of individual and collective behaviours in social sciences, with particular attention to the rationality problem and to the new frontiers of social neurosciences’ contribution.