It leaps from the insight that there is no knowledge of things without construction
of mental representations of them to the conclusion that entities are mental constructions. The
philosopher Immanuel Kant thought that he had accomplished a kind of Copernican revolution by
placing mind at the center of knowledge and reality. But idealism is actually attempting a kind of
Ptolemaic counterrevolution, as implausible as reactionary attempts to return the earth to the center of
the solar system or to deny human evolution. To develop my alternative, brain-based approach to
constructive realism, I will first discuss perception of objects and then move on to how inference
enables us to go beyond perception.