Brett is here omitting the influence of Aristotle in the intervening period between Plato and Plotinus. This, together with his projection of the prejudices of materialistic science upon the metaphysical("first principle") aspect of this discussion needs also to be borne in mind. The idea of cosmic reason was embraced by Aristotle as part of a comprehensive theory that could in its turn be used to respect scientific concern for describing and explaining a change in quantitative and relational terms(subjective-objective were for him merely "relational" categories). This Aristotelian theory stretched from the Oneness and goodness of Being which was Primary Pure Form, all the way down to a position of pure primary material. Primary Form on this account can in no way be correctly related to the relational term of the "subjective" or the consciousness of a being who introspects upon its own "contents of consciousness". Aristotle is in his theory characterising a great chain of Being which includes the Forms and the soul and the material of the body of the soul as well as the material of the external environment of the soul. This "metaphysical attitude" of Aristotle can not meaningfully be characterised as "psychological". It is rather a philosophical position arrived at through the various philosophical methods of elenchus (Socrates), dialectical reasoning as well as logical reasoning and explanation. The Metaphysics of Stoicism may well be problematically materialistic as Brett is suggesting in that its notion of causation was unnecessarily deterministic and this might in a sense follow from the limited view of causation we find in Plato who appears to believe the idea of "formal cause" suffices to describe and explain everything that needs describing and explaining. Aristotle criticised this position and elaborated upon the role of causation in description and explanation in terms of his famous "four causes" schema. Recent scholars(Jonathan Lear) have pointed out that the Greek word "aitia" is connected to knowledge and explanation. Jonathan Lear, therefore, writes about the four different fashions of characterising cause in descriptive and explanatory contexts. The interesting question to ask in this context is whether Plotinus subscribed to the Stoic view of deterministic causation or whether he would have regarded the Aristotelian view as more accurate. in this context we should also remind ourselves of the fact that a revered teacher of Plotinus in Alexandria, Ammonius Saccas, was both an expert in Platonic and Aristotelian Philosophy. Saccas, however, saw in Aristotelian Philosophy a natural continuation and sophistication of Plato's Philosophy, and disregarded Aristotelian criticism of Plato's position.