Immanuel Kant (1724–1804), a German philosopher, is regarded as one of the most influential thinkers of the history of Western philosophy. Exercising a significant influence today, Kant set the terms for metaphysics, epistemology, ethics, aesthetics, political philosophy and other fields.
On morality:
According to Kant, morality can not be rooted in happiness or pleasure because it is subjective and can vary from experience to experience. The moral status should be defined by our good will and duty rooted in reason. Kant formulated two principles of our moral actions:
1) Universalizability. Act only on that maxim by which you can at the same time will that it should become a universal law. For example, theft is immoral since we could not conceive of a world where this action was universalized.
2) Humanity as an end in itself. Act in such a way that rational beings can never be treated merely as a means to an end. Using somebody as a mere means is like using him as a device without agreement; often this kind of action includes making a false promise, attacks on the freedom and property of others, harms etc.
On transcendental idealism:
Kant argues that we cannot experience objects without being able to represent them in space and time. So, beyond the empirical realm, there can be no sensations of objects for the understanding to judge. In this context, Kant often used transcendental arguments in his works that start from some accepted aspect of experience, and then deduce what must be true for that type of experience to be possible.
On aesthetic judgments:
According to Kant, an aesthetic judgement has four key distinguishing features.
1) It is disinterested, meaning that we take pleasure in something because we judge it beautiful,
2) It is universal, meaning that an intrinsic part of such judgement is to expect others to agree with us,
3) It is subjective, meaning that there is no objective property of a thing that makes it beautiful,
4) It gives no knowledge of the object since it is grounded on feelings of the properties of the object, rather than on properties themselves. If I say "this painting is beautiful", I do not offer any information on that painting. It is not a true or false judgement, but a judgement that shows my attitude to a particular object.
