   The deviation from the hylomorphic ontology of Aristotle is apparent in the famous thought experiment that Avicenna devises, conceiving of a person suspended in air in total isolation from any physical or sensory  experience.[27] The purport of this experiment is to show the ability of a person to deduce the soul's existence intellectually, without assistance from the sensory or imaginative, material faculties of the soul. For Avicenna this proves that the soul is an independent intelligent substance, both prior to involvement with the world, and afterwards, when the corporeal organs that service the soul perish.