The significance of imagery or symbolism in the Enneads has long been a source of scholary contention. In 1961 Beierwaltes published his well-known article, “Plotins Metaphysik des Lichtes,” in which he studied Plotinus' extensive employment of the image of light. Beierwaltes starts out with an assumption that governs the way he looks at the metaphors in the Enneads. He assumes that figures of speech can be more or less adequate to the task of representation, and that representational adequacy depends upon the ontological approximation of image and archetype. Since it is incorporeal, light turns out to be the most appropriate image for the task of representing philosophical truth.

In Beierwaltes's view, light is not merely a metaphor when it is used to describe intellect, since it can succeed as an image of the intellect only when “there is a presence of the original in the image”. Visual seeing differs from intellectual seeing because the visual object is external to the subject whereas the intellectual object is internal to the subject. Thus vision can be either intellectual or perceptual, but light, as the medium of vision, remains the same entity in either mode.

Replies to Beierwaltes have been both numerous and extensive, but most interpreters believe that in the Enneads symbols have no independent value. The majority of scholars insist that, far from speaking of the adequacy of symbols, one should speak of the subordination of symbols, since metaphor only redescribes doctrine.