Immanuel Kant

“The young Kant's bold cosmology: the Milky Way is a flattened disc of stars, the faint 'nebulae' are other such systems, and the solar system formed by purely mechanical, Newtonian laws out of a primordial cloud of scattered matter — the first version of the 'nebular hypothesis.' Creation, he argues, is never finished, but spreads endlessly through infinite space; and he ends with speculations on the inhabitants of other planets.”

“The young Kant's elegant essay, written more as an observer of human nature than as a philosopher: on the two kinds of 'finer feeling' — for the sublime, which moves, and the beautiful, which charms — as they show themselves in nature, in human qualities and temperaments, in the relations of the sexes and in the characters of nations. Its last two sections reflect the prejudices of its age.”

“Kant asks what reason can know without experience, and answers with a 'Copernican revolution': space and time are forms of our intuition, and the categories, such as cause and substance, are rules of our understanding, so that we can know the world a priori as it appears to us — but never as it is in itself. Reason's attempts to know the soul, the world as a whole, and God end in illusion; and so knowledge is limited, to make room for faith.”

“Kant's short, clearer restatement of the 'Critique of Pure Reason,' written for teachers and readers who had found the Critique too difficult. Woken from his 'dogmatic slumber' by Hume, he asks how pure mathematics, pure natural science and metaphysics are possible — and concludes that metaphysics can become a science only through critique.”

“Kant's short, famous essay defines enlightenment as humanity's emergence from its self-incurred immaturity — the inability to use one's own understanding without another's guidance — and gives it a motto: 'Sapere aude! Have courage to use your own understanding!' Its condition is freedom: the freedom to make public use of one's reason in all matters.”

“Kant's short foundational work in ethics seeks the supreme principle of morality. Starting from the idea that nothing is good without limitation except a good will, it arrives at the categorical imperative — act only on a maxim you could will as a universal law; treat humanity always as an end, never merely as a means — and grounds it in the autonomy and freedom of rational beings.”

“Kant's second Critique shows that pure reason can be practical: that the moral law, which commands unconditionally, is a 'fact of reason' through which we know ourselves to be free. Duty, not happiness, is the ground of morality; respect for the law is its only motive; and the hope that virtue and happiness may at last be united leads reason to postulate immortality and God. It ends with the starry heavens above and the moral law within.”

“Kant's third Critique seeks to bridge the gulf between nature and freedom through the power of judgement. It asks what it means to call something beautiful or sublime — a pleasure without interest, valid for everyone, without a concept — explores genius and fine art, and then asks how we can understand living things as purposes, and the whole of nature as having a final end in man as a moral being.”

“Kant asks what remains of Christianity when it is read by reason alone. He finds in human nature a 'radical evil' — a propensity to put self-love above the moral law — that can be overcome only by a revolution of the heart; reads the Son of God as the ideal of moral perfection in our reason; describes the church as an 'ethical commonwealth' on the way to a pure religion of reason; and condemns as 'counterfeit service' every attempt to please God by anything except a good life.”

“Written in the form of a peace treaty, Kant's short book sets out the conditions for ending war forever: preliminary articles forbidding secret reservations, standing armies and interference in other states; and three definitive articles — a republican constitution in every state, a federation of free states, and a cosmopolitan right of hospitality. Nature itself, he argues, guarantees that peace will come.”

“Kant's mature system of ethics and law, built on the principle laid down in the 'Groundwork.' The Doctrine of Right sets out the rights of persons, property, contract, the state and punishment, the law of nations and the hope of perpetual peace; the Doctrine of Virtue sets out the duties we have to ourselves and to others, as ends we are bound to adopt — our own perfection and the happiness of others.”

“Kant's popular lectures on human nature, given for some thirty years and published near the end of his life: on the senses, imagination, memory, dreams and genius; pleasure, boredom, taste and the art of the dinner party; emotions and passions; temperament and character; and the human species, destined to cultivate, civilise and moralise itself in society.”

“Kant's lectures on education — known in English also as 'On Education' — argue that the human being is the only creature that must be educated, and can become human only through education. They set out the stages of discipline, culture, civilisation and moralisation; give practical advice on the care and physical training of children, the cultivation of the mind, and the forming of moral character; and ask the central question: how can freedom be cultivated under constraint?”