To begin to answer the question, "How can cognition create new meanings out of old?" we need to find a way in which existing meanings can interact to produce new meanings that inherit some of their meaning from the original meanings but have new, emergent meaning of their own. This is the problem of conceptual evolution. How can existing meanings interact to produce descendent meanings that are not copies of the originals? The theory of conceptual integration, otherwise known as "blending," is an attempt to provide a solution to the open problem of conceptual evolution. I will present the basic principles and mechanisms of conceptual integration and its role in the conceptual evolution.