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 stituted. An inductive history of this whole process is a principal part, as it is still a desideratum, in psychology. Much that is valuable for the explanation of its earlier stages has been contributed in the Dissertation on the “Primary and Secondary Qualities of Body” a dissertation which appears to us to form an important step of progress in this department of mental science.

The opposite to this theory of a consciousness of certain qualities of matter, which is itself styled Natural Realism, is the doctrine of Absolute Idealism, which denies to the material world any external independent existence. Intermediate between the two are the various hypotheses of representative perception or Hypothetical Realism.

It is evident that this alleged immediateness of our knowledge of the qualities of matter is to be contrasted, not merely with that sort of mediate knowledge which is implied in the possession of the results of inductive or deductive reasoning, but also with that other kind of mediate knowledge which, according to some philosophers, (and among others Sir William Hamilton, who has rediscovered and revived the old scholastic distinction of presentative and representative knowledge,) is implied in every act of memory and imagination. It is a more subtle analysis than the familiar one, which divides the propositions that compose what we believe, into those that are the result of reasoning, and those that are known by us intuitively, and it suggests some curious questions regarding the nature and economy of certain of our intellectual functions.