Critique of Practical Reason

Any thought or conclusion that is a priori comes purely from reason and intuition. It exists prior to any direct empirical evidence. An example of an a priori statement would be “Green apples are not red.”

An antimony is a pair of rational statements, a thesis and an antithesis, that contradict each other, yet are rationally true. Immanuel Kant identifies several apparent antimonies that emerge from attempts to use speculative reason to understand the transcendent and metaphysical. One example Kant himself gives is “either the desire for happiness must be the motive to maxims of virtue or the maxim of virtue must be the efficient cause of happiness” (92).

Autonomy is the ability of a rational being to act with free will, unrestrained by external forces. Kant believes every rational being possesses autonomy, rather than heteronomy, which is when a rational being is constrained by external forces and circumstances.