How did Plotinus describe the One, or the Good?

For Plotinus, the One—also referred to as the Good—is the ultimate, transcendent principle from which all reality proceeds. He maintained that this supreme principle is absolutely simple, undetermined, and beyond the reach of human thought or language. Because it lacks limitations, attributes, or divisions, it cannot be defined or named in any conventional sense.12

Plotinus often employed negative language to describe the One, not to define it, but to emphasize the inadequacy of human concepts in expressing a reality that transcends all being. Despite this, he viewed the One as a positive reality of superabundant excellence. It is the source of all perfections and the ultimate goal of the soul's return.12

For Plotinus, the One is not an object of knowledge; rather, it can only be experienced through a mystical union where the mind is raised to an immediate, non-dualistic awareness of its presence. This return to the source is the central focus of his philosophy, which he viewed as a way of life involving rigorous moral and intellectual purification.12