Aristotle's Refutation of Plato's Theory of Ideas Aristotle refutes Plato's Theory of Ideas on three basic grounds: that the existence of Ideas contradicts itself by denying the possibility of negations; that his illustrations of Ideas are merely empty metaphors; and that they theory uses impermanent abstractions to create examples of perception. Though the theory is meant to establish concrete standards for the knowledge of reality, Aristotle considers it fraught with inconsistencies and believes that the concept of reality depends upon all forms' correlations to other elements.