19th century idealists from Friedrich Hegel (1770-1831) to Francis Herbert Bradley (1846-1924) - unlike the earlier 18th century idealist George Berkeley (1685-1753) - were heavily influenced by Immanuel Kant (1724-1804).
Kant insisted that there are limits to what we can, in principle, know about reality, and that we necessarily look at the world in certain ways only; for example in terms of substance and cause.
These idealists concluded that the world as we see it is somehow derivative, apparent, relative, incomplete, and even contradictory. They used 'the absolute' as a term for reality as it really is, free from these limitations but unknowable by us. Baruch Spinoza (1632-1677) and the Greek philosopher Parmenides (early 5th century BC) have been seen as forerunners of this doctrine.
For absolute idealism see: objective idealism
A Quinton, Absolute Idealism (1972); reprint of Dawes Hicks lecture at British Academy in 1971
Also see:· eleaticism