In this article I aim to show how the sensus communis grounds – with the use of its maxims – the possibility of reflection, endowing the subject with a duty, that of becoming human, where becoming human presupposes self-education. Self-education entails on one hand overcoming one’s self interest or private feelings – that is what an aesthetic judgment demands: To love something other than one-self; on the other hand, and more fundamentally, self-education entails to place one-self under the indeterminate idea (...) of humanity. Like all ideas and ideals of reason, the idea of humanity places an unrealizable demand upon the subject, to become part of an idea, in this case, that of humanity; this demand can never be met. Nevertheless, it is the strive to meat such a demand that motivates the human being to become human. To do so the subject will need to reflect appropriating thus the world through the exercise of its judgment. (shrink)