Geoff Epstein, an advocate for math and science curriculums who prided himself on being an independent voice on the city’s School Committee, said Tuesday that he will not be running for a fourth term next fall. The Australian-born Epstein, a longtime resident of Newton, would frequently pipe up with questions during School Committee presentations, and during recent Board of Aldermen meetings about proposals to raise taxes for school projects was often seen sitting apart from his fellow committee members. Epstein said in an interview that enough independent members have been elected to the School Committee in recent years that he no longer felt the need to serve on the panel. The School Committee has become more open and decides issues based on data, Epstein said. He said his decision was also influenced by his youngest son’s graduation from Newton North High School next year. The School Committee’s vice chairman, Matt Hills, said Epstein helped the panel place more importance on certain issues, such as the need for more technology in the district.