Transcendental idealism in the context of "Immanuel Kant"

Arthur Schopenhauer (/ˈʃoʊpənhaʊər/ SHOH-pən-how-ər; German: [ˈaʁtuːɐ̯ ˈʃoːpn̩haʊɐ] ; 22 February 1788 – 21 September 1860) was a German philosopher. He is known for his 1818 work The World as Will and Representation (expanded in 1844), which characterizes the phenomenal world as the manifestation of a blind and irrational noumenal will. Building on the transcendental idealism of Immanuel Kant, Schopenhauer developed an atheistic metaphysical and ethical system that rejected the contemporaneous ideas of German idealism.

Schopenhauer was among the first philosophers in the Western tradition to share and affirm significant tenets of Indian philosophy, such as asceticism, denial of the self, and the notion of the world-as-appearance. His work has been described as an exemplary manifestation of philosophical pessimism. Though his work failed to garner substantial attention during his lifetime, he had a posthumous impact across various disciplines, including philosophy, literature, and science. His writing on aesthetics, morality and psychology has influenced many thinkers and artists.

In philosophy, a noumenon (/ˈnuːmənɒn/, /ˈnaʊ-/; from Ancient Greek: νοούμενoν; pl.: noumena) is knowledge posited as an object that exists independently of human sense. The term noumenon is generally used in contrast with, or in relation to, the term phenomenon, which refers to any object of the senses. Immanuel Kant first developed the notion of the noumenon as part of his transcendental idealism, suggesting that while we know the noumenal world to exist because human sensibility is merely receptive, it is not itself sensible and must therefore remain otherwise unknowable to us. In Kantian philosophy, the noumenon is often associated with the unknowable "thing-in-itself" (German: Ding an sich). However, the nature of the relationship between the two is not made explicit in Kant's work, and remains a subject of debate among Kant scholars as a result.

Idealism in philosophy, also known as philosophical idealism or metaphysical idealism, is the set of metaphysical perspectives asserting that, most fundamentally, reality is equivalent to mind, spirit, or consciousness; that reality or truth is entirely a mental construct; or that ideas are the highest type of reality or have the greatest claim to being considered "real". Because there are different types of idealism, it is difficult to define the term uniformly.

Indian philosophy contains some of the first defenses of idealism, such as in Vedanta and in Shaiva Pratyabhijña thought. These systems of thought argue for an all-pervading consciousness as the true nature and ground of reality. Idealism is also found in some streams of Mahayana Buddhism, such as in the Yogācāra school, which argued for a "mind-only" (cittamatra) philosophy on an analysis of subjective experience. In the West, idealism traces its roots back to Plato in ancient Greece, who proposed that absolute, unchanging, timeless ideas constitute the highest form of reality: Platonic idealism. This was revived and transformed in the early modern period by Immanuel Kant's arguments that our knowledge of reality is completely based on mental structures: transcendental idealism.

Edmund Gustav Albrecht Husserl (Austrian German: [ˈɛdmʊnd ˈhʊsɐl]; 8 April 1859 – 27 April 1938) was an Austrian-German philosopher and mathematician who established the school of phenomenology.

In his early work, he elaborated critiques of historicism and of psychologism in logic based on analyses of intentionality. In his mature work, he sought to develop a systematic foundational science based on the so-called phenomenological reduction. Arguing that transcendental consciousness sets the limits of all possible knowledge, Husserl redefined phenomenology as a transcendental-idealist philosophy. Husserl's thought profoundly influenced 20th-century philosophy, and he remains a notable figure in contemporary philosophy and beyond.

The Critique of Pure Reason (German: Kritik der reinen Vernunft; 1781; second edition 1787) is a book by the German philosopher Immanuel Kant, in which the author seeks to determine the limits and scope of metaphysics. Also referred to as Kant's "First Critique", it was followed by his Critique of Practical Reason (1788) and Critique of Judgment (1790). In the preface to the first edition, Kant explains that by a "critique of pure reason" he means a critique "of the faculty of reason in general, in respect of all knowledge after which it may strive independently of all experience" and that he aims to decide on "the possibility or impossibility of metaphysics".

Kant builds on the work of empiricist philosophers such as John Locke and David Hume, as well as rationalist philosophers such as René Descartes, Gottfried Wilhelm Leibniz and Christian Wolff. He expounds new ideas on the nature of space and time, and tries to provide solutions to the skepticism of Hume regarding knowledge of the relation of cause and effect and that of René Descartes regarding knowledge of the external world. This is argued through the transcendental idealism of objects (as appearance) and their form of appearance. Kant regards the former "as mere representations and not as things in themselves", and the latter as "only sensible forms of our intuition, but not determinations given for themselves or conditions of objects as things in themselves". This grants the possibility of a priori knowledge, since objects as appearance "must conform to our cognition...which is to establish something about objects before they are given to us." Knowledge independent of experience Kant calls "a priori" knowledge, while knowledge obtained through experience is termed "a posteriori". According to Kant, a proposition is a priori if it is necessary and universal. A proposition is necessary if it is not false in any case and so cannot be rejected; rejection is contradiction. A proposition is universal if it is true in all cases, and so does not admit of any exceptions. Knowledge gained a posteriori through the senses, Kant argues, never imparts absolute necessity and universality, because it is possible that we might encounter an exception.