‘It is a long road that separates Kant’s early criticisms of the moral philosophy of his time from the final form and systematic presentation of his practical philosophy in The Metaphysics of Morals. […] The complete answer to the foundational problem of moral philosophy would only be given by Kant in the Groundwork of the Metaphysics of Morals, of 1785, and in the Critique of Practical Reason, of 1788.

In these two works, Kant carried out the “propaedeutic” and foundational task of a critique of practical reason, preliminary to the exposition of the system of moral philosophy, which he called the “metaphysics of morals”. The execution of the philosophical program of transcendental investigation was embodied in the elaboration of a “metaphysics of nature” and a “metaphysics of morals”, both preceded, respectively, by the task of a critique of pure speculative reason and a critique of practical reason.

Kant’s philosophical program revolved around two poles: on one hand, the foundation of the new scientific knowledge, which had reached its paradigm in the Newtonian model of physics; on the other hand, the foundation of moral obligation in the idea of ​​“freedom”, conceived as rational autonomy – a conception that Kant traced back to Rousseau, whom he considered “the Newton of the moral world”.’

(From the Introduction by José Lamego)