Plotinus’ Treatise V.1 comes closer than any other to providing an outline of his entire spiritual and metaphysical system, and as such it may serve to some degree as an introduction to his philosophy. It addresses in condensed form a great many topics to which Plotinus elsewhere devotes extended discussion, including the problem of the multiple self; eternity and time; the unity-in-duality of intellect and the intelligible; and the derivation of intelligible being from the One. Above all, it shows that the so-called “three hypostases”—soul, intellect, and the One—are best understood not as a sequence of three things additional to one another, but as three levels of possession of the same content, so that each lower level—soul in relation to intellect and intellect in relation to the One—is an “image” and “expression” of its superior.

Plotinus exhorts the human soul to overcome its alienation from its own true nature and its divine origin by first recognizing itself as superior to the body and the same in kind as the animating principle of the entire cosmos, and then discovering within itself the still higher levels of reality from which it derives: intellect and, ultimately, the One or Good, the supreme first principle of all things. To do so the soul must redirect its attention inward and upward to become aware of the divinity which is always within it but from which it is distracted by the clamor of the senses.