The Soul in Islam Philosophy
The Existence of the Soul
All Muslim philosophers concerned themselves with the subject of the soul. Muslim philosophers recognised that the first issue that confronts the human mind with regard to the soul is its existence. We infer the existence of the soul from the fact that we observe bodies that perform certain acts with some degree of will. These acts are exemplified in taking nourishment, growing, reproducing, moving and perceiving. Since these acts do not belong to the nature of bodies, for this nature is devoid of will, they must belong to a principle they have other than bodies. This principle is what is called ‘soul’.
This argument is intended to prove the existence of the animal soul, which includes the plant soul. The soul is the source of acts performed by the will, not inasmuch as it is ‘a substance’ (an independent entity), but inasmuch as it is ‘the principle of such acts’. The rational soul, on the other hand, need not look outside itself to infer its existence. It is aware of its existence with immediacy, that is, without any instruments.