عنوان مقاله [English]
Price's theory of sensory perception is based on sensory data and Russell's theory of knowledge by acquaintance. Price separates between knowledge of sense-date and perceptual acceptance. In his view, belief in the external world takes place during these two stages. Sense data are mantel states that are subject to direct intuition and are infallible and perceptual acceptance also is a pseudo-intuitive act. Price's theory is an example of the “prima facie justification” theory in internalist foundationalism that is comparable with the view of Chisholm and Pollack and BonJour. Many critics believe that this theory is very optimistic and an example of dogmatic foundationalism that accept external world as mere assumption. However, Chisholm tries to revises this view by relying on concept of “self-presenting”. BonJour too by reliance on passivity in sensory perception and best explanation argument provides a base for knowledge of the external world. The result of these defenses shows the necessity of attention to different knowledge from propositional knowledge i.e. knowledge by presence and rational argument in believing to the external world. The main point is that the nature of knowledge consists of showing its object and this showing is prima facie evidence for the external reality that appeared to us in assuming the health of the senses and by best explanation argument this prima facie evidence becomes a good reason for believing to the external world.