But another member, Beverly Long, a retired school administrator who now teaches education at the Citadel, said that when she first moved to Charleston from Toronto in 2001, “the first question people asked me was, What church do you belong to?” Ms. Long attended Wednesday dinners at a Methodist church, for the social interaction, but never felt at home. Since her youth, she had doubted the existence of God but did not discuss her views with others.

Ms. Long found the secular humanists through a newspaper advertisement and attended a meeting. Now, she is ready to go public, she said, especially after doing some genealogical research recently. “I had ancestors who fought in the American Revolution so I could speak my mind,” she said.

Until recent years, the Secular Humanists of the Lowcountry were local pariahs. Mr. Silverman  whose specialty license plate, one of many offered by the state, says “In Reason We Trust”  was invited to give the invocation at the Charleston City Council once, but half the council members walked out. The local chapter of Habitat for Humanity would not let the Secular Humanists volunteer to build houses wearing T-shirts that said “Non Prophet Organization,” he said.

When their billboard went up in January, with their Web site address displayed prominently, they expected hate mail.

“But most of the e-mails were grateful,” said Laura Kasman, an assistant professor of microbiology and immunology at the Medical University of South Carolina.

The board members meeting in the Kasmans’ living room were an unlikely mix that included a gift store owner, a builder, a grandmother, a retired nursing professor, a retired Navy officer, an administrator at a primate sanctuary and a church musician. They are also diverse in their attitudes toward religion.

Loretta Haskell, the church musician, said: “I did struggle at one point as to whether or not I should be making music in churches, given my position on things. But at the same time I like using my music to move people, to give them comfort. And what I’ve found is, I am not one of the humanists who feels that religion is a bad thing.”