An Essay in Aid of a Grammar of Assent

by John Henry Newman

"An Essay in Aid of a Grammar of Assent" by John Henry Newman is a philosophical work completed in 1870. Taking twenty years to write, Newman challenges the idea that scientific standards of evidence should govern religious faith. He argues that formal logic fails in real-life decision-making and introduces the "illative sense"—a faculty that weighs evidence from multiple sources to reach belief. The work defends faith as rational, distinguishing between notional and real assent, and explores how we can legitimately believe what we cannot fully understand or prove.