When sending his Short Treatise to his Amsterdam friends he begs of them to be sure that nothing but the good of their neighbours will ever induce th… - Benedictus de Spinoza

With such a universal prevalence of idealism it is not surprising that Spinoza has long since been enlisted in the camp of the idealists. Unfortunately, there are even some Marxists who defend the tradition of the historians of philosophy, despite the fact that Feuerbach, to some extent Engels, and more recently Plekhanov have done a great deal in explaining Spinoza's materialistic views. We still have to struggle against this idealistic tradition, to prove to comrades from our own midst that Spinoza is not to be ranked among the idealists. In the last few years, two 'fronts' have been formed in connection with the treatment of Hegelian dialectics and Spinoza's world-conception: the Hegelian front and the Spinozistic front. The disagreements and disputes which are going on in our own midst focus on two basic points: the disputes about Hegel touch the foundations of our method, the differences of opinion with regard to Spinoza concern our world‑view and involve the conception of materialism itself. But, since method and world‑view are not separate from one another, the disputes and disagreements in the first area—those concerning method—are indissolubly connected with the disputes in the second area—those concerning world‑view. I shall not dwell further on this point; I wished merely to indicate the extent to which these two fronts are connected.

I say expressly, that the mind has not an adequate but only a confused knowledge of itself, its own body, and of external bodies, whenever it perceives things after the common order of nature; that is, whenever it is determined from without, namely, by the fortuitous play of circumstance, to regard this or that; not at such times as it is determined from within, that is, by the fact of regarding several things at once, to understand their points of agreement, difference, and contrast. Whenever it is determined in anywise from within, it regards things clearly and distinctly, as I will show below.

Thus we see, that the mind can undergo many changes, and can pass sometimes to a state of greater perfection, sometimes to a state of lesser perfection. These passive states of transition explain to us the emotions of pleasure and pain. By pleasure therefore in the following propositions I shall signify a passive state wherein the mind passes to a greater perfection. By pain I shall signify a passive state wherein the mind passes to a lesser perfection. Further, the emotion of pleasure in reference to the body and mind together I shall call stimulation (titillatio) or merriment (hilaritas), the emotion of pain in the same relation I shall call suffering or melancholy. But we must bear in mind, that stimulation and suffering are attributed to man, when one part of his nature is more affected than the rest, merriment and melancholy, when all parts are alike affected. What I mean by desire I have explained in the note to Prop. ix. of this part; beyond these three I recognize no other primary emotion; I will show as I proceed, that all other emotions arise from these three.