What is a religion? This seemingly simple question has proven difficult to answer — particularly for courts tasked with deciding the merits of claims for religious discrimination brought under Title VII of the Civil Rights Act of 1964. That federal law prohibits employers with 15 or more employees from discriminating on the basis of religion.

Although religious-discrimination claims tend to come from adherents of commonly recognized belief systems such as Judaism, Christianity, Islam, Hinduism and Buddhism, the definition of religion has elicited some controversy over the years. The debate recently reached a new octave thanks to an Ohio federal court’s decision to recognize that Title VII "plausibly" protects as a religion what at least some would argue is no more than a dietary preference or social philosophy: veganism.