rationalist

His father had been dead for eight years — and he’d been a scientist and a rationalist — but there he was, trying to comfort his son.

The unintended effect, however, is of cramped twin biographies, when what we’re here for is a drawn-out colloquy in a tight space: Lewis’ gentle prodding of a rationalist’s edges versus Freud’s fulminating about God’s existence.

The same contradictions that marked his father’s life went even deeper in Mr. Nashenas’s own: a secular man in a profoundly religious family; a rationalist in a society trapped in tribal ways.

They include atheists, agnostics, the culturally religious but not observant, rationalists and the spiritual but not religious.

There's a certain style of being a rationalist which is a good direction to go in.