Act in such a way that you treat humanity, whether in your own person or in the person of any other, never merely as a means to an end, but always at the same time as an end.
About This Quote
This sentence is Kant’s “Formula of Humanity” (or “Humanity as an End in Itself”), one of the central formulations of the categorical imperative in his moral philosophy. Kant presents it in the Groundwork of the Metaphysics of Morals (1785), written in the context of Enlightenment debates about whether morality can be grounded in reason rather than in theology, sentiment, or prudential calculation. In the Groundwork, Kant argues that moral requirements must be universally valid and derived from rational agency itself. The formula is introduced as a way to express the same fundamental moral law from a different angle: by focusing on the special status of rational beings (persons) as bearers of dignity, not mere market value.
Interpretation
Kant’s claim is that persons, as rational agents capable of setting ends and legislating moral law for themselves, possess an intrinsic worth (“dignity”) that forbids treating them as disposable tools. The prohibition is not against using others in any sense—ordinary cooperation, employment, and exchange are permissible—but against using them “merely” as means, i.e., in ways that bypass or undermine their rational consent and autonomy (coercion, deception, exploitation). The positive requirement—treating humanity always also as an end—demands respect for persons’ capacity to choose and pursue ends, grounding duties such as honesty, non-manipulation, and beneficence. It is a cornerstone for later rights-based and deontological ethics.
Variations
1) “So act that you use humanity, whether in your own person or in the person of any other, always at the same time as an end, never merely as a means.”
2) “Act so that you treat humanity, whether in your own person or that of another, always as an end and never as a means only.”
3) “So act as to treat humanity, whether in your own person or in that of any other, in every case as an end withal, never as means only.”
Source
Immanuel Kant, Groundwork of the Metaphysics of Morals (Grundlegung zur Metaphysik der Sitten), 1785, Section II (the “Formula of Humanity” / “Humanity as an End in Itself” formulation of the categorical imperative).
