  During the last two decades of the twentieth century, philosophical production of the IIF-UNAM greatly  increased.[27] Among the philosophers who contributed are: Margarita Valdés who works on applied ethics, philosophy of language and mind, epistemology, and more recently on the history of analytic philosophy and philosophy in general in Latin America; Paulette Dieterlen who works on political philosophy, specifically on poverty and distributive justice and Olbeth Hansberg working in philosophy of mind, especially on emotions, perception, consciousness and Davidsonian philosophy. Mark Platts, of British origin, moved to Mexico where he published Ways of Meaning in 1979 (second edition in 1997) and Moral Realities: An Essay in Philosophical Psychology (1991), where he explores the concept of desire and develops an anti-Humean theory of moral motivation. He influenced several IIF-UNAM members, including Lourdes Valdivia, Olbeth Hansberg, Salma Saab, Guillermo Hurtado and Maite Ezcurdia. Carlos Pereda (originally from Uruguay) works mainly on ethics, epistemology, and political theory, but also on speech acts and linguistic communication. Since then, younger generations of philosophers have diversified and deepened the analytic  program.[28]