Martin Heidegger

Martin Heidegger (26 September 1889 – 26 May 1976) was a German philosopher, widely recognised as one of the most influential in the 20th century. If you happen to be in a sadistic mood, find a Heidegger fan and ask them what he was a member of from 1933 and until its dissolution.

Biography
Heidegger was born in rural Messkirch, Germany. Initially, he studied theology at a Jesuit seminary, but later switched to philosophy at the University of Freiburg. He obtained his Ph.D. in 1914 and became a Privatdozent. During World War I, he served as a soldier, never leaving Germany. Heidegger worked as a senior assistant to Edmund Husserl at Freiburg until 1923 when he became a professor at the University of Marburg. In 1928, he returned to Freiburg as Husserl's successor. In 1933, Heidegger joined the Nazi Party and briefly served as the university's Rector before resigning in 1934. After World War II, his teaching was suspended by the French Occupation Authority due to his Nazi past, but in 1951 he was reinstated as a Professor Emeritus with all privileges. He continued to teach regularly until 1958 and occasionally by invitation until 1967. He passed away on May 26, 1976, and was buried in the Meßkirch cemetery.

Etymological method
Throughout his works, Heidegger constantly made arguments from and through etymology. Some consider this the single most characteristic and controversial move of his method.

Critics have pointed out that Heidegger often relied on questionable and even definitively false etymologies, like implying connection between Ereignis 'event' and eigen 'one's own', 'appropriate'. Even if these etymologies were right, there's still the problem of etymological fallacy. However, he himself expected it, writing that his thinking doesn't rely on history of words. Rather, as he put it, he was using etymology "to ponder that essential realm as the one in which the matter named through the word moves", whatever that means. What he seems to be saying, and what many of his defenders argue, is that etymology is just a tool for thought. In this sense, it wouldn't matter if it's linguistically sensible, as long as it opens insights into new ideas.

It's not clear how much this helps the method. In the first section of the Genealogy of Morals, Nietzsche used etymology pretty sincerely, to argue that certain moral concepts originated from resentments built up from the weak's subjugation by the strong. Similarly later thinkers influenced by Heidegger like Aleksandr Dugin or Yuk Hui make very sincere appeals to the history of words.