About Kant, Putnam and internal realism

To speak about the inheritances of modern thought and to refer to Kant is something obvious. But when Putnam assures that Kant was "the first internal realist", it is important to take it into account. Focusing only in the phase of this internal Putnamian realism- and particularly exactly as it is expressed in Reason, Truth and History-this work tries to detect some of the places in the Critique of Pure Reason which could back up this statement and give it sense. What both texts understand by rationality and truth will guide us to the place where - beyond the theoretical and historical distance - both philosophers coincide.