For example...

For example, when one compares the existence of the states of one’s soul (not their whatnesses) with the existence of the soul (not with its whatness) he sees that the occurrence of passive qualities, such as fear, hope, happiness and sadness, etc., depends on the existence of the soul, so that on the assumption of the absence of the existence of the soul, no room remains for their existence. This is opposed to the existence of the soul, which does not need them and can also occur without them.

In view of this comparison, existents are divided into two groups. The first group is called ‘accident’ and the second group is called ‘substance.’ If one equates the concept of substance with ‘non-accident,’ one can divide all existents into substances and accidents so that the Necessary Existent, Blessed and Exalted, may also be considered an instance of substance, as with some Western philosophers. In this way the above mentioned division will be a primary division.

But Islamic philosophers divide contingent existence into substance and accident. For this reason they do not consider the application of substance to the Necessary Existent in Itself to be correct. On the other hand, some Western philosophers have expressed some doubts about the existence of substance. For example, Berkeley denied the existence of corporeal substance, and Hume had doubts about the substance of the soul, as well.

However, those who accept the existence of objective accidents and have denied the existence of their substances have unwittingly accepted the existence of many sorts of substance in place of one sort of substance! For example, in case the phenomena of the soul are not considered accidents of the soul, they will not need any subject, and in this case each of them will be a particular substance.

Likewise, if the attributes of bodies are not considered accidents in need of a subject, inevitably they themselves will become corporeal substances. For what is meant by being a substance is nothing more than that the existence of a contingent existence does not need a subject.