The role of the body in appearance of sensory perception in Ibn Sina and Mulla Sadra's perspectives

The first level in acquired knowledge which is achieved by human beings, is sensory knowledge. By sensual knowledge, the imaginary and rational knowledge are made. Hence, discussion on the quality of sensual perception is important. Since the sensory knowledge is provided by external senses, the question arises about the process of emergence of perceptions, what role does the body and its faculties play? Do the body and its faculties have played a role in itself or by accident? Ibn Sina and Mulla Sadra's discussion on psychology and knowledge and perception has certain principles which lead to the different views on this issue. first of all, in this paper Mulla Sadra and Avicenna’s elements on the question have been explained and then their approach to the body role in appearance of sensual knowledge has been taken into consideration. As a result, according to Avicenna’s sensual perception is material and done by the brain, therefore, the body and its faculties have the main role in emergence of the perception, but according to Mulla Sadra, sensual perception is immaterial entirely, and body and its faculties are regarded as an instrument and preparatory cause.