How do we acquire knowledge through a sensory input from our environment? In The Enigma of Perception, D.L.C. Maclachlan revives the traditional causal representative theory of perception which dominated philosophical thinking for hundreds of years by revealing the important element of truth the theory contained. The traditional theory was not a complete explanation of perception, because it presupposed a causal system including both the physical objects and the subjective experiences. The pattern of inference from sensations to external objects, which lies at its heart, is nevertheless...