I support a fundamental principle stressed by the Encyclopédie, that the Unity of Knowledge is the direct consequence of the unity of the human brain. All of us are animated by what Claude Bernard called a ‘kind of thirst for the unknown’ which ennobles and enlivens scientific inquiry. We must humbly confess for now our immense ignorance – ignoramus. But to satisfy Claude Bernard’s ‘ardent desire for knowledge’ we should never say, as some philosophers still do, ignorabimus about the human brain. Thanks to recent developments in neuroscience, we can now propose a common set of brain processes that account for the production of the diversity of knowledge. Thanks to these processes, we can work on a reunification of the true, the good and the beautiful, not as a uniform, monotonous culture, but as a network of cooperative diversity favouring intellectual and emotional exchanges among disciplines.