Concept, Sense and Reality

New versions of old problems in Philosophy have appeared in new disciplines, as Neurosciences and Artificial Intelligence, about the nature of Meaning. They concern Concepts, Sense and Reality. To orient ourselves in these notions, we must choose a right Metaphysics. For that, we go back in the past, to the discussions of Aquinas, Scotus and Ockham. However, we encounter also modern thinkers, like Brentano, Husserl and Russel, or Frege, Putnam and Fodor, and more ancient thinkers, Stoics and Epicureans, under the insight of Deleuze. On many points, Duns Scot and Ockham, were not surpassed in their rigour and their finesse. We expose their dynamical view of Concepts, the related scheme of signification, its connection with real things and relations, and a scheme of understanding and knowledge. We show that the conclusions and interrogations are compatible with a mathematical view of neural networks, based on categories (topos, stacks, of Grothendieck), and topological dynamics (singularities, of Thom).