Leonard Nelson (July 11, 1882, Berlin – October 29, 1927, Göttingen) was a German mathematician and philosopher. He was part of the Neo-Friesian School and a friend of the mathematician David Hilbert, and devised the Grelling–Nelson paradox with Kurt Grelling. During his doctorate at Georg August University of Göttingen he was advised by Julius Baumann, and his dissertation was titled Jakob Friedrich Fries und seine jüngsten Kritiker. He was critical of Hegel in his work, Progress and Regress in Philosophy. He is also known for defending the idea of animal rights in his work System of Ethics. Together with Minna Specht he was the founder of Internationaler Sozialistischer Kampfbund.
He was an insomniac and died young from pneumonia.
- ^ Nelson, Leonard, System of Ethics, Yale University Press, New Haven, 1956, p. 142.