Arthur Evans was born on Oct. 12, 1942, in York, Pa. His father was a factory worker who had dropped out of elementary school, and his mother ran a beauty shop in the front room of the family house. Mr. Evans attended Brown University on a scholarship and there joined a group of self-styled “militant atheists.”

He left Brown after three years and headed for Greenwich Village, having read in Life magazine that it welcomed gay people. In New York, he transferred to City College and switched his major from political science to philosophy. Graduating in 1967, he entered the doctoral program in philosophy at Columbia, where he studied ancient Greek philosophy and participated in antiwar protests.

But, becoming disenchanted with academia, he withdrew from Columbia in 1972 and moved to rural Washington State, where he and a companion, calling themselves the Weird Sisters Partnership, homesteaded a small patch of forest land and lived in a tent.

When the Washington experiment failed, Mr. Evans and his companion moved to San Francisco. There, he and Mr. Offen opened a Volkswagen repair business they named the Buggery.

While living in Washington, Mr. Evans had spent his winters in Seattle researching the historical origins of the counterculture. After settling in San Francisco, he wrote “Witchcraft and the Gay Counterculture,” a 1978 book tracing homophobic attitudes to the Middle Ages, when people accused of witchcraft, the book contended, were being persecuted in part for their sexuality, often their homosexuality.

He went on to write “Critique of Patriarchal Reason” (1997), arguing that misogyny and homophobia have influenced supposedly objective fields like logic and physics.

Mr. Evans is survived by his brother, Joe.

Growing up, Mr. Evans had hid his sexual orientation, though he himself was aware of it at 10, he said. By November 1970, when he was scheduled to appear on “The Dick Cavett Show” with other gay leaders, he had still not told his parents that he was gay. But, by his account, he did tell them he was going to be on national television. Thrilled, they told friends and neighbors to tune in.

Mr. Evans later said he regretted his handling of the matter.