There are no whole truths; all truths are half-truths. It is trying to treat them as whole truths that plays the devil.

Whitehead’s remark belongs to his mature philosophical critique of “misplaced concreteness”—the habit of treating abstractions as if they were complete realities. In the late 1920s, after turning from mathematical logic to metaphysics and the philosophy of science, he repeatedly warned that any statement or theory captures reality only under a selected set of abstractions and emphases. The line is commonly cited from his Harvard-period lectures and writings, where he stresses that truths are partial perspectives within a wider process of experience. The “devil” is the dogmatic impulse to absolutize a partial formulation and then force the world to fit it.

Whitehead’s remark captures a central theme of his philosophy: reality is complex, processual, and resistant to final, all-encompassing formulations. Any statement we call a “truth” is made from a particular standpoint, with selective emphasis and abstraction. The danger arises when such partial insights are treated as exhaustive—when a useful model, principle, or doctrine is absolutized and applied without regard to context, limits, or competing considerations. In that sense, “the devil” is dogmatism: the moral and intellectual harm that follows from forcing the world to fit a simplified certainty. The quote is often invoked to defend pluralism, intellectual humility, and the need to balance perspectives in science, politics, and ethics.