This paper proposes that each area of the cortex maintains and updates the organism's knowledge of specific aspects of the world through reciprocal and topographically connected thalamic nuclei. The cortex, responsible for interpreting stimuli and generating actions, integrates multiple sources of expertise, creating conflicting hypotheses that are then integrated by thalamic neurons and sent back to the cortex. The thalamus acts as an "active blackboard," displaying the current best reconstruction of the world. The paper reviews evidence for this theory and suggests experimental tests. The author also discusses the role of the thalamus in motor control and attention, proposing that the thalamus gates data rather than focusing attention, and that the massive cortico-thalamic projection is more consistent with the thalamus serving as a blackboard. The paper concludes with potential experimental tests, including demonstrating the effect of the cortico-thalamic projection on the lateral geniculate nucleus (LGN).This paper proposes that each area of the cortex maintains and updates the organism's knowledge of specific aspects of the world through reciprocal and topographically connected thalamic nuclei. The cortex, responsible for interpreting stimuli and generating actions, integrates multiple sources of expertise, creating conflicting hypotheses that are then integrated by thalamic neurons and sent back to the cortex. The thalamus acts as an "active blackboard," displaying the current best reconstruction of the world. The paper reviews evidence for this theory and suggests experimental tests. The author also discusses the role of the thalamus in motor control and attention, proposing that the thalamus gates data rather than focusing attention, and that the massive cortico-thalamic projection is more consistent with the thalamus serving as a blackboard. The paper concludes with potential experimental tests, including demonstrating the effect of the cortico-thalamic projection on the lateral geniculate nucleus (LGN).