The Treatise of Human Nature finds its full meaning in the interpretative cultural environment in which it was written. This article aims to point out the strong influence that the Newtonian system exerted in the young Hume and how the rejection of hidden causes and the search for an observable common cause are the guide that inspires Hume to look for the principles of the science of man denying, therefore, an a priori access to universal truths, establishing the scientific observation (...) as the only possible way for the science of man. Hume does not deny the validity of induction and the possibility of reaching general knowledge but takes newtonian proposal to develop the science of man. (shrink)