Let's not forget that Part II of Spinoza's Ethicscomes after Part I and before Parts III, IV and V. We aren't going to understand his account of the human mind unless we see it in relation to his account of the way in which we have to think of the world, if we are to hold that the world can be understood. Look at Part I and his account of the kind of life which is possible for man and of how these possibilities may be exploited so as to achieve ‘blessedness’. We aren't even going to understand the kind of account of the human mind that is in question here (what the problems are and what interest Spinoza has in answering them), unless we have a prior grasp of his conception of the world and the conditions under which it can be understood. Spinoza himself gives us a clear signal in this direction in the short preface to Part II. And we might put that alongside Part IV, Proposition 26.

The whole of the Ethics deals with the question of what it is to understand something, and the account of the human mind in Part II is part of his treatment of that question. I mean this remark in a very strong sense. Spinoza's account of substance and its attributes and modes is not an account of some thing, an entity and its features, though it may often sound like that. He himself says, quite explicitly, that to think in this way is to think with the greatest possible degree of confusion, at the very lowest level. And, a fortiori, when he says, for instance, that the individual human mind is a mode of the divine mind, we shall miss entirely his meaning if we have some strange picture of God as a sort of superman, composed of literal homunculi. He takes it to be confusion to think ‘either the nature of God appertains to the essence of created things, or else that created things can be or be conceived without God’. Such confusions come from not keeping to ‘the proper order of philosophical thinking’ and from ‘putting into the first place what they call the objects of sensation’ instead of the divine nature.