This thesis considers the city and its architecture the extreme condition under which the endless discussion around the human being way of thinking takes place. More precisely, the research assumes the city as the place where the displacement of mindset principles, categories and catalogue of objects is materialized into Form, becoming inhabitable. This radical definition of Form is therefore the subject matter of Urban Morphology and Building Typology and justifies the seductive uniqueness of the city with respect to any other possibility of existence of the above mentioned discussion. At least since its original inception, the greek polis, to discuss about the architecture of the city therefore implies to discuss about the ground of the thinking which made the city possible. The thesis identifies two main conditions under which the existence of the city is made possible. The former is the identification of the agents ( i.e. the driving forces) who reciprocally recognize claiming a role in the city coming into being and therefore decide to engage within the related discussion. The latter is the existence of a language as the result of the discussion about what the city should be. The type definition encompasses both the aspects, becoming the specific embodiment of the city collective project. Since the “conditions of possibility” of the discussion are neither neutral nor universal but historical, this thesis analyzes the city and its architecture as the place of an harsh conflict among different positions developed through space and time. The conflict not necessarily occurs within the existing city, putting into question its achieved certainties and implicit rationality. Sometimes it happens that the discussion leads to the crisis of the city itself and its architecture, demanding for a complete renewal of its principles, categories and related catalogues. Assuming the perspective of the crisis as a challenging one, the thesis starts questioning the Enlightenment revolution discussion around the city as a symmetrical discussion on the principle of the Enlightenment itself, in order to get rid of the Ancien Régime and to abruptly enter into the realm of Modernity. Furthermore, the thesis analyzes the way the city reacted to that revolution, as a mean of better understanding the way the western society coped with the subject matter of the Modern way of thinking itself. Through the transformation of the city, its principles, its categories and its catalogues, the thesis follows the transformation of the human being mindset as a reaction to the introduction of Modernity and its meaning. Towards that perspective, it recognizes an important threshold in the discussion occurred around the ’70 of the XX century. In fact, a crises of a new kind appeared at that time. It was not anymore under discussion an historical specific form of the city, but the possibility itself of existence of the city as an embodied displacement of that discussion was radically put into question. This is what Post-Modernity was deeply prompting. As an immediate consequence it was put into question the possibility of existence of the type itself. The thesis identifies in that aporia the main struggle put at stake nowadays, which is still unresolved and too often remains unquestioned. The thesis concludes that the crisis of the type identifies with the sunset of the western civilization, and that renouncing to the type definition as the subject matter of the discussion implies to renounce to those principles upon which the civilization process is grounded: to lead the discussion to a necessarily materialized conclusion, however provisional and partial it should be, of course to be discussed again and again. Moreover, the thesis concludes that to renounce to the type project means to renounce to the city, blurring its entity into a generic space of living.