With the Brazilian military coup d'état, in 1964, he was forced into exile and worked as professor at Yale University, in the United States, and later at Cambridge University and the University of Paris (Sorbonne), in France.
Vid militärkuppen i Brasilien 1964 tvingades han i exil och arbetade som professor vid Yale University i USA och senare vid Cambridge University och Paris universitet (Sorbonne) i Frankrike.