A member of marginalized religious groups throughout his life and a proponent of what was called "rational Dissent", Priestley advocated religious toleration (challenging even William Blackstone), helped Theophilus Lindsey found the Unitarian church and promoted the repeal of the Test and Corporation Acts in the 1780s. As the foremost British expounder of providentialism, he argued for extensive civil rights, believing that individuals could bring about progress and eventually the Millennium. Priestley's religious beliefs were integral to his metaphysics as well as his politics and he was the first philosopher to "attempt to combine theism, materialism, and determinism," a project that has been called "audacious and original."