Neither materialistic nor spiritualistic monism satisfied William James. The individual is a mere puppet in the hands of absolute substance, be it universal matter or universal mind. The possession of truth is not an in itself but a preliminary means to vital satisfaction. Knowledge is an instrument for the sake of life, existing as practical utility. True ideas are those we can assimilate, validate, corroborate, and verify.
Truth is, therefore, useful because it is true, it is true because it is useful.
James's empiricism opposes classical rationalism and traditional empiricism. He denies that whatever is rational is real. To reach reality we must take experience as it exists before it has been manipulated by conceptual thinking. Reality is the flux of our sensations coming from what we know not. It is the totality of consciousness, experience permeated with thought.