The fundamental principles of the transcendent Theosophy have had deep effects in different philosophical areas. Among the principles related to soul, substantial movement and gradating of existence is more prominent. Among discussions related to soul, the one related to the relationship between soul and faculties has been more subjected to change as it has been linked with these principles. Between the two divisions being discussed, that is between the one related to the subjectivity of soul and faculties, and the one related to their unity or multiplicity of existence, the first one has been subjected to less disagreement. Avicenna and Sadra, with minute differences, believe in the soul as being the doer of all the actions including perceptual and motivating actions, and the Perceiver of all the perceptions; but the original difference between the two philosophers becomes apparent in the second division, in which contrary to Avicenna who believes in the multiplicity of the existence of soul and faculties, Sadra puts the theory of the existential unity of soul and faculties. They relate principles of their theories about the relationship between soul and faculties to the relationship between soul and body; therefore, the same disagreements are observed in this regard as well.
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