Critique of Practical Reason

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.

Any internal inclination that compels an individual to obey a moral law is a categorical imperative. According to Kant, the categorical imperative operates by provoking a sense of duty or respect for moral laws.

Causality refers to when a being (whether a living being or a metaphysical being like God), an object, or an event causes an effect upon another object or event. For example, a cat knocking a coffee cup off a table and breaking it would be an example of causality.

For Kant, cognition is any thought by a rational being that concerns an object.

In terms of free will, the determining grounds are the internal and external factors that shape how an individual decides to exercise their will, especially in regards to following a moral law.

Empiricism is the philosophical belief that knowledge has to be primarily gained or can only be gained through the bodily senses. Empirical reasoning would be the use of reason based on evidence available to the senses, such as observation.

Freedom is one of Kant’s three postulates, along with the existence of God and the immortality of the soul. By “freedom,” Kant means specifically an individual’s free will.

In contrast to autonomy, which is the ability of every rational being to exercise their free will, heteronomy is when rational beings are completely constrained by forces and circumstances outside of themselves.

Holiness is when a human perfectly fulfills moral laws through their free will. Kant argues that such a state is impossible for humans with their limited perspectives and lifespans. Since humans strive toward holiness despite their inability to reach it, Kant proposes that the soul must be immortal—thus holiness is achievable in the afterlife if not in earthly existence (99).

In Kant’s philosophy, a law is a principle that is universal and unconditional (meaning not subjective and based on circumstance). This is in contrast to maxims, which are subjective and conditional.

Unlike a law, which is universal and objective, a maxim is a general rule an individual follows that is subjective (based on circumstances).

A moral law is a principle that is objective and universal, making it a law that can be determined through the use of practical reason. A sense of duty and respect is what compels individuals to obey moral laws.

A noumenon is a metaphysical being or concept that exists outside of the bodily senses, such as God or the soul.

A phenomenon is any object or event that can be observed and experienced through the senses.

Any statement that can be assumed to be true is considered a postulate. In Critique of Practical Reason, Kant bases his arguments around three postulates: free will, the existence of God, and the immortality of the human soul.

By Kant’s definition, practical reason is the use of reason to understand lived experience. This is different from speculative reason, which uses abstract and theoretical arguments to reach conclusions about beings and matters that are outside bodily experience.

Speculative reason is the use of abstract or theoretical principles and argumentation in order to reach conclusions about beings, objects, and ideas that cannot be experienced through the senses.