THIS book is an essay in the speculative treatment of certain problems, suggested but not usually discussed in the course of a thorough empirical study of mental phenomena.Inasmuch as these problems all relate to the real nature and actual performances and relations of the human mind, the essay nay properly be called metaphysical. Let it be confessed, then, that the author comes forward with a treatise in metaphysics,- in the more special meaning of that term. I think, however, that in spite of the marked disfavor into which all metaphysics has fallen in certain quarters, no detailed apology...