In the more detailed treatment of his subject Ibn Sina conforms entirely to Farabi’s Logic. This agreement would perhaps be more apparent to us, if the logical works of his predecessor were extant in a more complete form. He frequently lays stress on the defectiveness of the intellectual constitution in man, which is urgently in need of a logical rule. Just as the physiognomist infers from the external features the character of the nature within, so the logician is called upon to derive from known premises that which is unknown. How easy it is for the errors of appearance and desire to insinuate themselves into a process of that kind! A struggle with Sense is required in order that the life of representation may be elevated to the pure truth of the Reason, through which any knowledge of a necessary kind is gained. The divinely-inspired man, but he alone, can dispense with Logic, precisely as the Bedouin is independent of an Arabic Grammar. The question of Universals is also treated in a manner similar to that which is adopted by Farabi. Prior to any plurality, every thing has an existence in the Mind of God and of the Angels (the Sphere-Spirits); then as material form it enters upon plurality, to be raised finally in the intellect of man to the universality of the Idea. Now just as Aristotle has distinguished between First Substance (Individual) and Second Substance (cogitable as a Universal), so Ibn Sina similarly makes a distinction between First and Second Notion or Intention (Maʻnâ, intentio). The First is referred to the things themselves, the Second to the disposition of our own thought. 4. In Metaphysics and Physics Ibn Sina is differentiated from Farabi chiefly through the fact that, by not deriving Matter from God, he places the Spiritual at a higher elevation above all that is Material, and in consequence heightens the importance of the Soul as an intermediary between the Spiritual and the Corporeal. From the conception of the Possible and the Necessary, the existence of a Necessary Being plainly follows. According to Ibn Sina we should not seek to demonstrate the existence of a Creator from his works, but rather should deduce, from the possible character of all that is, and all that is thinkable in the world, the existence of a First and Necessary Being, whose essence and existence are one. Not only is every sublunary thing of a ‘possible’ nature, but even the heavens are, in themselves, merely ‘possible’. Their existence becomes ‘necessary’ through another existence which transcends all ‘possibility’ and therefore all plurality and mutability. The ‘absolutely Necessary’ is an unbending Unity, from which nothing multiplex can proceed. This first One is the God of Ibn Sina, of whom many attributes may of course be predicated, such as thought &c., but only in the sense of negation or relation, and in such a way that they do not affect the Unity of his essence.