The mind has been a great bugbear to all philosophers. In seeking to find out what things are in themselves as distinguished from what they appear to be, the ontologist, like any other enquirer, must ultimately resort to the mind for data on which to base his specula tions. But all knowledge acquired through the mind comes invested with the limitations under which it works. Everything that is known is tinged with the colour of the mind perceiving it. The metaphysician, therefore, who suspects that things are not what they appear to be, concludes that things in them selves, — the noumena underlying the pheno mena, — are inconceivable and unknowable, though he is instinctively led to believe in them. As opposed to him there is a metaphy sician of another school, who holds that what is known or conceivable can alone be said to exist, and that therefore whatever is unknown and unknowable and even inconceivable can never be said or thought to exist.