Kant's Groundwork of the Metaphysics of Morals › Autonomy and the Foundation of Morality

Having laid out the categorical imperative, Kant faces a deeper question. Why should we be moral at all? What gives the categorical imperative its authority? Kant's answer is autonomy: > Autonomy of the will is the property the will has of being a law to itself. ::: {.callout-note title="Autonomy"} Literally "self-law," autonomy is the capacity to give oneself the moral law. For Kant, we are free not when we follow our desires but when we govern ourselves by principles we rationally endorse. Heteronomy, by contrast, is being governed by external forces: desires, social pressure, threats, or rewards. ::: When we act morally, we are not obeying commands imposed from outside, whether by God, society, or our own desires. We are governing ourselves according to laws we give ourselves as rational beings. This self-legislation makes us truly free. Consider the contrast with heteronomous action. When I act from desire, my will is determined by something external to my rational agency: the pull of appetite, the push of fear, the weight of social expectation. I am not self-governing. I am being moved. But when I act from duty, recognizing the moral law through my own reason and choosing to follow it, I am genuinely autonomous. I am the author of my action in the deepest sense. This is why morality and freedom, for Kant, are inseparable. To be free is to be moral. To be moral is to be free. A will that is truly self-governing would necessarily give itself the moral law, because the moral law is simply what pure practical reason requires. Any other "law" would reflect external determination (desire, inclination, coercion) and thus would not be genuine self-legislation.