 This account does not yet make clear why Royce thought that epistemology must lead to ontological idealism; that becomes clearer in his subsequent works. Royce’s next major statement of his idealism came in The Spirit of Modern Philosophy (1892). The second part of the book more fully develops Royce’s own arguments for idealism. Here Royce gives a clear definition of his conception of idealism and adds to the previous argument from error a second argument, from meaning. The core of this argument is that the intended object of an expression or thought must itself be conceived or understood in some way, so that we always mean what are in some sense our own ideas, although of course at any particular moment we hardly know or understand everything about the object to which we refer; that is why the idea that is the ultimate object of reference may be much greater than the idea that refers. In Royce’s words,