On August 18, 1994, the Israeli scientist, philosopher and national gadfly Yeshayahu Leibowitz died, at the age of 91.

Israel has never had anyone else quite like Leibowitz. He made his living as a biochemist and neurophysiologist, but having also been trained as a philosopher, he was a frequent and outspoken commenter on politics and religion. He often expressed his opinions in a provocative – if not downright offensive – manner, but for all of his dogmatism, he was prepared to talk with anyone, and became legendary for his willingness to travel around the country to carry on dialogue. He was especially beloved among young people, whom he also received regularly in his modest apartment, in Jerusalem’s Rehavia neighborhood.

Yeshayahu Leibowitz was born in Riga, Latvia (then part of the Russian Empire), on January 29, 1903. His father, Mordechai Kalman Leibowitz, was a lumber merchant. His mother was Frieda Leibowitz. He received a classical gymnasium education, and was schooled in Jewish subjects at home.

In 1919, his family fled revolutionary-era Russia for Berlin. He began his university studies there in both chemistry and philosophy, and received a PhD in chemistry in 1924. That was followed by medical studies, which he finished at the University of Basel in 1934, after Germany had come under Nazi rule.

By the following year, he had moved to Mandatory Palestine, settling in Jerusalem.

Leibowitz would remain in Jerusalem for the rest of his life, most of it on the faculty of the Hebrew University and of its medical school. He lectured not only in biochemistry and neurophysiology, but also in philosophy and the history of science. Polymath that he was, he also edited several volumes of the Hebrew Encyclopedia.

His younger sister Nehama (1905-1997) http://www.haaretz.com/israel-news/2.489/1997-a-modest-torah-teacher-who-invented-interactive-study-dies.premium-1.515102 , who immigrated to Palestine in 1930, was also a legendary scholar – who in the days before the internet reached thousands of people from all walks of life with her weekly lessons on the Bible.

A strictly observant Jew

As a philosopher of religion and a strictly observant Jew, Yeshayahu Leibowitz insisted that the value of the mitzvot, the religious commandments, was to be found in their coming from God, in whom one’s belief had to be unconditional and blind. Seeking practical benefit from religious observance voided it of its significance, he insisted, and the decision to be observant had to be made freely.

The great paradox in Leibowitz is that his opinions about morality and human relations were those of a liberal humanist, but that it didn’t derive from his understanding of Judaism.

Almost immediately after the Six-Day War of 1967, while most other Israelis were still ecstatic from the military victory and jubilant about having access to Jerusalem’s Old City and the West Bank, along with the other territories, Leibowitz was already warning that maintaining control of the territories would have a corrosive and corrupting effect on Israel. It would, he predicted as early as 1968, turn into a “secret-police state, with all that this implies for education, free speech and democratic institutions.”

Unlike national religious Zionists, he did not view the establishment of the state as the “beginning of redemption,” and said that ascribing holiness to either the “Jewish state” or even the Land of Israel itself was akin to idolatry. He also urged complete separation of religion and state.

Leibowitz’s iconoclasm could be refreshing, but at times it could seem that he went out of his way to upset people. Most notably, he described soldiers serving in the territories as “Judeo-Nazis,” and in 1993, he even encouraged them to refuse such service.

A short time later, when it was announced that he was to be awarded the Israel Prize for his life’s work, the prime minister, Yitzhak Rabin, said he would boycott the ceremony. In turn, Leibowitz said he would forgo the prize, wanting – in an unusual gesture for him — to avoid an unpleasant scene.

Leibowitz remained active until his final day, and died in his sleep of natural causes.