By asserting the objectivity of the physical world, naturalism identifies the existence and the conditions of existence of the physical world with existence and the conditions of existence in general. It forgets that the world of the physicist necessarily refers back, through its intrinsic meaning, through the subjective world which one tries to exclude from reality as being pure appearance, conditioned by the empirical nature of man, which is incapable of reaching directly to a world of things in themselves. But while the world of the physicist claims to go beyond naive experience, his world really exists only in relation to naive experience.