There he prepared for the entrance exams to the École Normale Supérieure, meanwhile receiving his license and maîtrise level degrees in philosophy at the Université Paris 1 Panthéon-Sorbonne.

In 1982 he defended a doctoral thesis in mathematics at Université Paris I, where, in 1988, he also completed his doctorat d’Etat, under the direction of Jean-Toussaint Desanti, on George Boole’s algebra of logic.

In 1982, Diagne returned to his native country to teach philosophy at Cheikh Anta Diop University in Dakar, where he became vice-dean of the College of Humanities.

He is a member of the scientific committees of Diogenes (published by UNESCO’s International Council for Philosophy and Humanistic Studies), CODESRIA (Conseil pour le développement de la recherche en sciences sociales en Afrique), and of the African and Malagasy Committee for Higher Education (CAMES), as well as UNESCO's Council on the Future.

In October 2007, he was invited to participate in a white paper commission on the defense and national security in the French Senate in Paris.