MacKenna-Plotinus: Intelligible Realm

Further, admitting that there is an Intelligible Realm beyond, of which this world is an image, then, since this world-compound is based on Matter, there must be Matter there also. Enneads   II,4,4

The dark element in the Intelligible, however, differs from that in the sense-world: so therefore does the Matter - as much as the forming-Idea presiding in each of the two realms. The Divine Matter, though it is the object of determination has, of its own nature, a life defined and intellectual; the Matter of this sphere while it does accept determination is not living or intellective, but a dead thing decorated: any shape it takes is an image, exactly as the Base is an image. There on the contrary the shape is a real-existent as is the Base. Those that ascribe Real Being to Matter must be admitted to be right as long as they keep to the Matter of the Intelligible Realm: for the Base there is Being, or even, taken as an entirety with the higher that accompanies it, is illuminated Being. Enneads II,4,5

Nor may we grant that this world is of unhappy origin because there are many jarring things in it. Such a judgement would rate it too high, treating it as the same with the Intelligible Realm and not merely its reflection. Enneads II,9,4

They hope to get the credit of minute and exact identification by setting up a plurality of intellectual Essences; but in reality this multiplication lowers the Intellectual Nature to the level of the Sense-Kind: their true course is to seek to reduce number to the least possible in the Supreme, simply referring all things to the Second Hypostasis - which is all that exists as it is Primal Intellect and Reality and is the only thing that is good except only for the first Nature - and to recognize Soul as the third Principle, accounting for the difference among souls merely by diversity of experience and character. Instead of insulting those venerable teachers they should receive their doctrine with the respect due to the older thought and honour all that noble system - an immortal soul, an Intellectual and Intelligible Realm, the Supreme God, the Soul’s need of emancipation from all intercourse with the body, the fact of separation from it, the escape from the world of process to the world of essential-being. These doctrines, all emphatically asserted by Plato, they do well to adopt: where they differ, they are at full liberty to speak their minds, but not to procure assent for their own theories by flaying and flouting the Greeks: where they have a divergent theory to maintain they must establish it by its own merits, declaring their own opinions with courtesy and with philosophical method and stating the controverted opinion fairly; they must point their minds towards the truth and not hunt fame by insult, reviling and seeking in their own persons to replace men honoured by the fine intelligences of ages past. Enneads II,9,6