George Berkeley (1685-1753) one of the earliest theorists who said that the only thing humans experience directly is their own perceptions, or secondary qualities.

Berkeley offered an empirical explanation of the perception of distance, saying that people learn to associate the sensations caused by the convergence and divergence of the eyes with different distances. Berkeley denied materialism, saying instead that reality exists because God perceives it. Humans can trust their senses to reflect God's perceptions because God would not create a sensory system that would deceive us.

List of books: George,Berkeley