Plotinos: Complete Works, v. 1 In Chronological Order,...

Intelligence exists (as intelligence) because it thinks existence. Existence exists (as existence) because, on being thought, it makes intelligence exist and thinks.229 There must therefore exist something else which makes intelligence think, and existence exist, and which consequently is their common principle. In existence they are contemporaneous and substantial, and can never fail each other. As intelligence and existence constitute a duality, their common principle in this consubstantial unity that they form, and which is simultaneously existence and intelligence, the thinking subject and the object thought; intelligence as thinking subject, and existence as object thought; for thought simultaneously implies difference and identity.