Whence do finite things or individuals arise, if they can have no existence by the side of substance? They are only the product of our deceptive apprehension. There are two chief ways of knowledge—the intuitive, through the reason, and the imaginative. To the latter belong the knowledge of experience, and all that is abstract, superficial, and confused; to the former, the collection of all fitting (adequate) ideas. It is only the fault of the imagination that we should look upon the world as a manifoldness of individuals; the manifoldness is only a form of representation. The imagination isolates and individualizes what the reason sees together in its unity. Hence it is only as considered through the imagination (experience or opinion) that modes are _things_; the reason looks upon them as necessary, or, what is the same thing, as eternal.
Such are the fundamental thoughts and features of Spinoza’s system. His _practical philosophy_ yet remains to be characterized and in a few words. Its chief propositions follow necessarily from the metaphysical grounds already cited. First, it follows from these, that what is called free will cannot be admitted. For since man is only a mode, he, like every other mode, stands in an endless series of conditioning causes, and no free will can therefore be predicated of him. The will must thus, like the body (and the resolution of the will is only a modification of the body), be determined by something other than itself. Men regard themselves as free only because they are conscious of their actions and not of the determining causes. Just so the notions which one commonly connects with the words good and evil, rest on an error as follows at once from the conception of the absolute divine causality. Good and evil are not something actually in the things themselves, but only express relative conceptions which we have formed from a comparison of things with one another. Thus, by observing certain things we form a certain universal conception, which we thereupon treat as though it were the rule for the being and acting of all individuals, and if any individual varies from this conception we fancy that it does not correspond to its nature, and is incomplete. Evil or sin is therefore only something relative, for nothing happens against God’s will. It is only a simple negation or deprivation, which only seems to be a reality in our representation. With God there is no idea of the evil. What is therefore good and what evil? That is good which is useful to us, and that evil which hinders us from partaking of a good. That, moreover, is useful to us which brings us to a greater reality, which preserves and exalts our being. But our true being is knowledge, and hence that only is useful to us which aids us in knowing; the highest good is the knowledge of God; the highest virtue of the mind is to know and love God. From the knowledge of God we gain the highest gladness and joy of the mind, the highest blessedness. Blessedness, hence, is not the reward of virtue, but virtue itself.