- 1857 – Eugen Bleuler, Swiss psychiatrist and eugenicist (d. 1940).
- 1878 – Władysław Witwicki, Polish psychologist, philosopher, translator, historian (of philosophy and art) and artist (d. 1948).
- 1930 – Félix Guattari, French psychotherapist and philosopher (d. 1992).
Paul Eugen Bleuler (30 April 1857 to 15 July 1939) was a Swiss psychiatrist and humanist most notable for his contributions to the understanding of mental illness.
He coined several psychiatric terms including “schizophrenia”, “schizoid”, “autism”, depth psychology and what Sigmund Freud called “Bleuler’s happily chosen term ambivalence”.
Władysław Witwicki (30 April 1878 to 21 December 1948) was a Polish psychologist, philosopher, translator, historian (of philosophy and art) and artist. He is seen as one of the fathers of psychology in Poland.
Witwicki was also the creator of the theory of cratism, theory of feelings, and he dealt with the issues of the psychology of religion, and the creation of secular ethics. He was one of the initiators and co-founders of Polish Philosophical Society. He is one of the thinkers associated with the Lwów-Warsaw school.
Pierre-Félix Guattari (30 March 1930 to 29 August 1992) was a French psychoanalyst, political philosopher, semiotician, social activist, and screenwriter.
He co-founded schizoanalysis with Gilles Deleuze, and ecosophy with Arne Næss, and is best known for his literary and philosophical collaborations with Deleuze, most notably Anti-Oedipus (1972) and A Thousand Plateaus (1980), the two volumes of their theoretical work Capitalism and Schizophrenia.