1. the belief or assumption that one’s sense perceptions provide direct knowledge of external reality, unconditioned by one’s perceptual apparatus or individual perspective. Since the advent of Cartesianism, most philosophy has assumed that such a position is untenable. The cognitive development theory of Jean
2. in social psychology, the tendency to assume that one’s perspective of events is a natural, unbiased reflection of objective reality and to infer bias on the part of anyone who disagrees with one’s views. See false-consensus effect.