From the perspective of Cartesian doubt, this article explores the concept of the limitations of reasoning through the use of the Kantian words 'boundary' and 'barrier' in his Critique of Pure Reason. Hegel's critical dialogue with Kant is presented focusing on the limitation that the latter imposed on reason for the acquisition of the true knowledge of philosophical/metaphysical objects. For this purpose, the Hegelian position is presented from its discussion on the second chapter of the first section of the The (...) Doctrine of Being and references are made to conceptual elements of the Phenomenology of Spirit. (shrink)