 In question 20 of his commentary on Aristotle’s Categories, Simon argues that substances are either compound or simple. In addition, all created substances are a composition of essence and being. Compound substances are also composed of matter and form. The reason why all created substances are composed of essence and being is that being is not part of their essence, but given to them extrinsically by the first being. Thus, Simon strongly suggests that he is committed to the real distinction between essence and being.