A philosophy from which was derived the later philosophy and literature of transcendentalism. It is based upon the concept of transcendence, the rising to a state beyond sense experience, which was developed by the Greek philosopher Plato. Within his concept of transcendence Plato affirmed the existence of absolute goodness that he characterized as something not describable and only knowable through intuition.
Later religious leaders influenced by Plato applied his concept of transcendence into their descriptions of divinity. Generally this is understood to mean that God can neither be understood nor described in terms of pure experience. This doctrine that God is transcendent is a basic tenet in the orthodox forms of Judaism, Christianity, and Islam.
Some religious mystics oppose the recognized transcendency of God doctrine, and refute it when claiming that God is also immanent in nature and in the soul of man, and is, therefore knowable through direct experience. This latter belief often embodies the theory of pantheism, as opposed to theism referring to the transcendency of God.
During the late Middle Ages scholastic philosophers more narrowly defined the terms "transcendent" and "transcendental" to give both terms a more general meaning so they might apply to many things. These scholastics recognized six transcendental concepts: essence, unity, goodness, truth, thing, and something which in Latin reads, ens, unum, bonum, verum, res, and aliquid.
The first technical distinction between the terms "transcendent" and "transcendental" was made by the German philosopher Immanuel Kant (1724-1804). Kant reserved the term "transcendent" for entities such as God and soul which are said to be beyond human experience and unknowable. The term "transcendental" Kant reserved to signify prior thought forms: the innate principles which gives the mind the ability to formulate its perceptions and make experience intelligible.
The term "transcendental philosophy" Kant applied to the study of the pure mind. This led to the term "transcendentalism" being applied almost exclusively to doctrines of metaphysical idealism.