Kant proceeds to motivate the need for the special sort of inquiry he calls a metaphysics of morals: “That there must be such a philosophy is evident from the common idea of duty and of moral laws.” The moral law must “carry with it absolute necessity.”

The Critique of Pure Reason is Kant’s response to this crisis. Its main topic is metaphysics because, for Kant, metaphysics is the domain of reason – it is “the inventory of all we possess through pure reason, ordered systematically” (Axx) – and the authority of reason was in question.

Kant’s theory is an example of a deontological moral theory–according to these theories, the rightness or wrongness of actions does not depend on their consequences but on whether they fulfill our duty. Kant believed that there was a supreme principle of morality, and he referred to it as The Categorical Imperative.

People have a duty to do the right thing, even if it produces a bad result. So, for example, the philosopher Kant thought that it would be wrong to tell a lie in order to save a friend from a murderer.

For Aristotle, eudaimonia is the highest human good, the only human good that is desirable for its own sake (as an end in itself) rather than for the sake of something else (as a means toward some other end).

Kant does believe that, all other things being equal, it is better to be happy than to be miserable. And he wouldn’t think that looking out for our own happiness is immoral. Looking out for people’s happiness follows from their intrinsic and infinite value as autonomous, free, rational beings.

Pure practical reason (German: reine praktische Vernunft) is the opposite of impure (or sensibly-determined) practical reason and appears in Immanuel Kant’s Critique of Practical Reason and Groundwork of the Metaphysic of Morals. It is the reason that drives actions without any sense dependent incentives.

Roughly speaking, we can divide the world into beings with reason and will like ourselves and things that lack those faculties. Moral actions, for Kant, are actions where reason leads, rather than follows, and actions where we must take other beings that act according to their own conception of the law into account.

In the decades before the publication of the Critique of Pure Reason, Kant was a metaphysical dualist who offered a positive account of mind/body interaction. He believed that these assumptions generated two main difficulties for understanding mind/body interaction.

Immanuel Kant was a German philosopher during the Enlightenment era of the late 18th century. His best-known work is the ‘Critique of Pure Reason.

Kant also argued that his ethical theory requires belief in free will, God, and the immortality of the soul. Although we cannot have knowledge of these things, reflection on the moral law leads to a justified belief in them, which amounts to a kind rational faith.

Kant. What is Enlightenment. Enlightenment is man’s emergence from his self-imposed nonage. Nonage is the inability to use one’s own understanding without another’s guidance.

The goal of the Enlightenment thinkers was to enlighten—or inform—the public. They aimed to convince others of their ideas. Their hope was to crush superstition, intolerance, and slavery. They wanted to make people “freer, richer, and more civilized.”