This belief is commonly called monism, and in particular, Russell (and G.E. Moore) were reacting to the absolute idealism dominant then in Britain.

Unlike absolute idealism, pluralistic idealism does not assume the existence of a single ultimate mental reality or "Absolute".

He argued vigorously against both logical positivism and associated philosophers (for example, Bertrand Russell) as well as absolute idealism (such as F.H. Bradley).

Josiah Royce (1855-1916), an American defender of absolute idealism.

Schopenhauer noted that Hegel created his absolute idealism after Kant had discredited all proofs of God's existence.

The resulting "absolute idealism" dominated Western philosophy up to the beginning of the 20th century.

Consistently, his own view combined monism with absolute idealism.

Russell associates it with pragmatism, objective idealism and the absolute idealism of Hegel.

A species of absolute idealism, British idealism was a philosophical movement that was influential in Britain from the mid-nineteenth century to the early twentieth century.

Several modern researchers object this translation, and the accompanying label of "absolute idealism" or "idealistic monism".