Whether this desire for sex is moderate or not, it is usually called lust. - Benedictus de Spinoza

Everyone is by absolute natural right the master of his own thoughts, and thus utter failure will attend any attempt in a commonwealth to force men to speak only as prescribed by the sovereign despite their different and opposing opinions.

...Aside from a little Spinoza and Plutarch, I have read nothing since my return, as I am quite occupied by my present work. ...I have read lately some amazing theological things, which I have intermingled with a little of Plutarch and Spinoza. ...Just now, I am reading in the evening, Kant's Critique of Pure Reason, translated by Barni, and I am freshening up my Spinoza. [Original in French: Présentement je lis, le soir, le Critique de la raison pure, de Kant, traduit par Barni et je repasse mon Spinoza.] ...If only I do not make a failure also of Saint-Antoine. I am going to start working on it again in a week, when I have finished with Kant and Hegel. These two great men are helping to stupefy me, and when I leave them I fall with eagerness upon my old and thrice great Spinoza. What genius, how fine a work the Ethics is! [Original in French: Pourvu que je ne rate pas aussi saint Antoine! Je vais m'y remettre dans une huitaine quand j'en aurai fini avec Kant et avec Hegel! Ces deux grands hommes continuent à m'abrutir et, quand je sors de leur compagnie, je tombe avec voracité sur mon vieux et trois fois grand Spinoza! Quel génie! quelle œuvre que l'Éthique!] ...I knew Spinoza's Ethics, but not the Tractatus Theologico-Politicus. The book astounds me; I am dazzled, and transported with admiration. My God, what a man! what an intellect! what learning and what a mind! [Original in French: Je connaissais l'Éthique de Spinoza, mais pas du tout le Tractatus théologico-politicus, lequel m'épate, m'éblouit, me transporte d'admiration. Nom de Dieu, quel homme! quel cerveau! quelle science et quel esprit!]

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.