Kant was born in, spent his whole life in, and died in Konigsberg in East Prussia. He is usually portrayed as having led a comically ordered life, taking the same walk at the same time each day, with neighbours looking on and setting their watches. Though he never married or travelled, Kant was both a popular socialite and respected as an authority on a wide range of subjects. His lectures at the university covered topics ranging from geography and anthropology to physics and mathematics.

Prior to his famous philosophical works, Kant wrote on physics and cosmology. His Universal Natural History and Theory of the Heavens postulated the existence of Uranus, which was not to be discovered until more than a century later.

The Copernican Revolution

Among Kant’s great contributions to philosophy is his “Copernican Revolution”. He noted that we are actively involved in interpreting the world, rather than passive recipients of experiences, and that the way that we are therefore limits the way that we can perceive the world to be. The world can only be perceived as temporal, ordered, etc., for these are preconditions of experience.

Kantian Ethics

Kant made an equally significant contribution to ethics, seeking to develop a moral system founded on reason. He took a deontological approach, stressing the importance of acting from duty irrespective of one’s inclinations. He distinguished hypothetical imperatives, which tell us what to do to achieve our ends, from categorical imperatives, which tell us what to do irrespective of our ends. Morality, for Kant, consists of categorical imperatives; we ought to do our duty not because it serves our interests or furthers our desires, but for its own sake.

Kant expressed the fundamental principle of morality from which more specific maxims can be derived, the “Categorical Imperative”, in three forms, which he took to be equivalent:

The Formula of the Law of Nature: “Act as if the maxim of your action were to become through your will a universal law of nature.”

The Formula of the End in Itself: “Act in such a way that you always treat humanity, whether in your own person or in the person of any other, never simply as a means, but always at the same time as an end.”

The Formula of the Kingdom of Ends: “So act as if you were through your maxims a law-making member of a kingdom of ends.” Violation of these principles, according to Kant, contradicts reason. As reason is universal, possessed by all humanity, morality too is universal; we are all bound by duty.

Kant and Religion

Though Kant was a theist, his did not shy away from criticising arguments for God’s existence. In his Critique of Pure Reason, he rejected the ontological argument, arguing that existence is not a predicate and that an ontological proof of God’s existence is therefore impossible. Kant’s objection there is still considered by many to be the strongest objection to the ontological argument, counting decisively against it.

His positive contribution to the field came in the form of a moral argument for the existence of God. This argument is usually characterised in terms of justice: morality is a rational enterprise, morality is only a rational enterprise only if goodness is rewarded and evil punished, goodness is rewarded and evil is punished only if there is a God; therefore, there is a God.

An alternative, but still Kantian, argument has been constructed along the following lines, however: we have an obligation to be perfect, can only have an obligation to be perfect if we can be perfect, and can only be perfect if God exists; therefore God exists.