Christopher Jacob Boström, an Swedish Idealist philosopher, studied and also taught at Uppsala University, where he was assistant professor of "practical philosophy" (the philosophy of morals, law, and religion) from 1828 to 1833. After an interlude as tutor to the royal princes in Stockholm from 1833 to 1837, he resumed his academic teaching, and from 1842 to 1863 he held the chair in practical philosophy. His "rational idealism" is a spiritualistic metaphysics, combining traits from Plato's theory of ideas, Gottfried Wilhelm Leibniz's monadology, and George Berkeley's immaterialism. With arguments, some of which are reminiscent of Berkeley's, he tried to show that nothing but minds and their perceptions exist.

Two of his more original, though hardly very convincing, arguments were these: (1) Truth means agreement between the perception and the perceived object. Perfect truth, therefore, is perfect agreement; and perfect agreement is the...