William Blake opens the third part of his epic poem, Jerusalem: the Emanation of the Giant Albion, with an astonishing remark. “He never can be a friend of the Human Race who is the Preacher of Natural Morality or Natural Religion.”

The declaration is shocking because today, two hundred years since he first printed these lines, naturalistic explanations of morality and religion have become standard. Even amongst champions of Blake.

But what did he mean? What did he propose as an alternative? And why might that matter now?

An earlier version of this essay is in the current issue of Vala, the magazine of The Blake Society.

Mark Vernon’s new book is Awake! William Blake and the Power of the Imagination - out in June 2025 (UK), September 2025 (US). Pre-order now!