The ambiguities and uncertainties which Plotinus exhibits in theorising on the origin of Matter, are due not only to the conflicting influences of Plato and Aristotle, but also to another influence quite distinct from theirs. This is the Stoic cosmology. While utterly repudiating the materialism of the Stoics, Plotinus evidently felt attracted by their severe monism, and by the consistent manner in which they derived every form of existence from the divine substance. They too recognised a distinction between Form and Matter, the active and the passive principle in Nature, but they supposed that the one, besides being penetrated and moulded by the other, had also been originally produced by it. Such a theory was well suited to the energetic and practical character of Stoic morality, with its aversion from mere contemplation, its immediate bearing on the concrete interests of life. Man was conceived as an intelligent force, having for his proper function to bring order out of chaos, ‘to make reason and the will of God prevail,’ and this ideal appeared to be reflected in the dynamic constitution of Nature. With Plotinus, on the other hand, as with Aristotle, theory and not practice was the end of life, or rather, as he himself expressed it, practice was an inferior kind of theorising, an endeavour to set before oneself in outward form what should properly be sought in the noetic world where subject and object are one.[490] Accordingly, while accepting the Stoic monism, he strove to bring it into close agreement with Aristotle’s cosmology, by substituting contemplation for will as the creative principle in all existence, no less than as the ideal of happiness for man.