Proposition XXI.
A thing composed of two elements has necessarily their composition as the cause of its present existence. Its existence is therefore not necessitated by its own essence; it depends on the existence of its two component parts and their combination.
Proposition XXII.
Material objects are always composed of two elements [at least], and are without exception subject to accidents. The two component elements of all bodies are substance and form. The accidents attributed to material objects are quantity, geometrical form, and position. [[148]]
Proposition XXIII.
Everything that exists potentially, and whose essence includes a certain state of possibility, may at some time be without actual existence.
Proposition XXIV.
That which is potentially a certain thing is necessarily material, for the state of possibility is always connected with matter.
Proposition XXV.
Each compound substance consists of matter and form, and requires an agent for its existence, viz., a force which sets the substance in motion, and thereby enables it to receive a certain form. The force which thus prepares the substance of a certain individual being, is called the immediate motor.