Another approach to understanding knowledge of reality is idealism, which views reality as dependent on or even constituted by minds. This view is more compatible than is empiricism with the constructive nature of perception and inference, but grossly overestimates the contributions that minds make to the world. 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.