"Descartes defined matter in terms of extension. It could just as well be defined in terms of time, for both the one and the other are external conditions of its existence in spatial and temporal relations. Thus both become also the necessary conditions of measurement for all thinking minds, which are themselves limited by place and time, but they never become the essence of matter. Spinoza struggled for a long time against this Cartesian explanation, probably because he felt that something about it was not clear. He was not satisfied with his teacher's sharp distinction between matter and spirit, but, since he lacked a unifying intermediate conception, what could he do? Unfortunately then, in his Ethics he still took matter for extension, that is space, and set it up beside thought, an entirely different kind of thing. Now he was indeed on the way to a very intricate confusion."

“Humanam impotentiam in moderandis et coercendis affectibus servitutem voco; homo enim affectibus obnoxius sui juris non est sed fortunæ in cujus potestate ita est ut sæpe coactus sit quanquam meliora sibi videat, deteriora tamen sequi.”

“Meum institutum non est verborum significationem sed rerum naturam explicare”

“Hic conatus aliquid agendi et etiam omittendi ea sola de causa ut hominibus placeamus, vocatur ambitio præsertim quando adeo impense vulgo placere conamur ut cum nostro aut alterius damno quædam agamus vel omittamus; alias humanitas appellari solet.”

“veritas norma sui et falsi est”

“Ordo et connexio idearum idem est ac ordo et connexio rerum”

“[B]y Natura naturans we must understand what is in itself and is conceived through itself, or such attributes of substance as express an eternal and infinite essence, that is … God, insofar as he is considered as a free cause. But by Natura naturata I understand whatever follows from the necessity of God's nature, or from God's attributes, that is, all the modes of God's attributes insofar as they are considered as things which are in God, and can neither be nor be conceived without God.”