Lightning flashes. But is there a lightning doing the flashing? Or is it a single process? And similarly, when ‘you choose’ is there a ‘you’ ‘choosing’, or is this again one process? Nietzsche argues free will is an illusion. Lightning flashing is one process, and so are you. Free will is an invention created to make us feel guilty and deserving of punishment. Writes Alexandre Fillon.

In a famous passage from the Critique of Practical Reason [1], Kant aims to show how we can be sure of our free will in ordinary experience. It is not a proper demonstration, since it is impossible to prove freedom empirically, as empiricism is ruled by the determinism of the laws of nature, but rather an example that helps us to understand the relationship between morality and free will. At the same time, Kant’s strategy is to point out the limits of determinism, the position that denies the existence of free will. Let us imagine a hedonist, someone who feels incapable of resisting the inclination of his or her desires. With such a character, we might doubt the ability of their will to choose freely between one action or another. Show them a house where they can satisfy their deepest desires, but with gallows in front, and establish a clear rule: if you give in to temptation, you will be hanged. Kant ironically suggests that any hedonist will contain themselves, thanks to their own will and, above all, out of the fear of imminent death. It is thus possible, in some circumstances, to successfully fight against most of the external inclinations that seem to govern our lives. Nevertheless, a strong determinist, like Hobbes for example, would argue against Kant that this case does not prove in any way the ability of our own will to determine our actions by itself, which is the central aspect of free will. The will of the hedonist is not liberated from any external force, or even from any desire: they are merely obeying a desire more powerful than all others, the desire to stay alive, not to be killed.

Kant anticipated such an objection, which is why he proposes to confront our hedonist, or anyone else, with a much more difficult dilemma. Suppose you are forced by a prince, i.e. a powerful man, to make a false testimony against an innocent person, in order to put him to death; a case of pure injustice. You may comply because of the fear of death yourself, as in the previous case. Even stunned by fear, anyone can consider the possibility to disobey this tyrant and choose to die rather than take part in an unjust murder. According to Kant, this hesitation, preferring to obey the moral law above all else indicates that we are free beings, even if it is not followed by action. Beyond the classic debates with determinism, what is particularly interesting in this passage is the thesis that only morality manifests our true freedom as autonomy. When our will is realising the moral law, we can overcome the most powerful external determinations. Ultimately, the freest action is at the same time always a moral action. Morality reveals freedom (it is the ratio cognoscendi of freedom, says Kant), but freedom remains the fundamental principle, the keystone of morality (its ratio essendi).