Plotinus's essays explicate his version of the Neoplatonist philosophy, presenting his views on cosmology, moral philosophy, the nature of souls, the nature of mind, the nature of reality, and the physical universe.
His series of six discourses in fifty-four essays, complete by the time of his death in 270, affirm the general themes common to the Platonic tradition, placing particular emphasis on three points: the ultimate nonmaterial nature of reality; the possibility of gaining real knowledge about the world and its basic laws; and the goodness, sacredness and unity of the universe.
Something of a mystic, Plotinus maintains that all things in nature (souls) are alive, dynamic, and in a process of change (becoming), a process that can have no higher significance unless it be established that there exist higher fixed principles that do not themselves change.
He argues that these principles are rationally ordered and constitute the structure of being, a belief that engenders a cosmology consisting of several levels of reality, the lower of which derive their meaning and significance from those above.
The lowest of these levels is the material world; the highest is the fusion of all higher principles: an indefinable ultimate principle that Plotinus calls “the One.”
The One, by emanation, creates a second order, Reason and the Forms, which in turn generates the Soul.
Matter, the final level, dark and unreal, traps the human soul, whose goal is escape and return to the One.
Plotinus believes that one can reestablish the connection of the Soul with Reason through the pure practice of ascetic moral training and the contemplation of beauty.
Ultimately, through a mystical experience (described variously by Plotinus as "ecstasy," "self-surrender," and "flight yonder, of the alone to the Alone"), one can arrive at knowledge of, and therefore unification with, the One.