In a previous essay, I suggested that the difference between sensibles and intelligibles is not so much a matter of the material versus the immaterial but a matter of distinct modes of consciousness by which we access different kinds of reality. We grasp sensibles with our senses, but we grasp intelligibles with our intelligence. According to Plato, this leads to a categorical distinction between the kinds of knowledge that we can have of these different kinds of reality. We need to look closely at the Greek vocabulary here and the standard translations of these words because students often misunderstand this distinction.

On the sensory side of this distinction, we have the Greek word δόξα (doxa). This noun is related to the verb δοκεῖν which means, “to seem,” or “to appear.” This is how sensibles show up in our experience. They seem a certain way at a particular time, from a particular angle. I look out my window, for example, and I see the dark green of late summer maple leaves rustling gently in the wind. The color seems, right now, a little dim since the sun is low in the sky and is obscured by thin clouds. As the hours of the morning pass, however, the green awakens into the full light of day. My memory stitches all these seemings together so that I do not perceive the trees as changing color but rather as revealing their true color more fully under different lights. As I walk from my building to where the high school classes are held, I see these same trees from different angles by the path. Their bark seems to have a rougher texture up close, it seems dusty to the brush of my fingertips, and I smell in the air the subtle green hints of living wood.

Such seemings are the only way for me to experience these trees. They do not show up to my consciousness at all without seeming one way or another. I recognize, however, a gap between the way the tree seems to me and the way the tree must be in itself. At any given moment, I only see one side of the tree, but I realize that it has a backside. I can walk around and see this other side easily enough, but when I do this, only that side seems to me, and the immediate seeming of the other side is lost, only to be held in memory. Hence, from a plurality of momentary seemings reinforcing each other, correcting each other, and fleshing out a fuller picture we form some conception of the sensible object’s features. No matter how much we examine the tree, however, further inspection can always reveal more that we had not previously seen. Hence, we come to recognize that all knowledge based on seeming is always from a particular perspective, bound to particular moments, under particular conditions, always falling short of completeness.

So far, I have avoided translating the noun δόξα at all, relying instead on its verbal cousin. Traditionally, in the context of Plato, this word has been translated as “opinion” in contrast to “knowledge,” but it is strange in English to call the convictions I have about the tree mere “opinion”—as though they were akin to my political views. When I touch the tree and feel the dusty texture of its gray bark, I would never say that I have an “opinion” about how it feels. As far as I am concerned, the texture of the bark is an immediate fact, and we would ordinarily say that I “know” this fact.

Nevertheless, it is, admittedly, knowledge of a certain kind, knowledge rooted very much in the here-and-now appearance of this particular tree to me. As much as I try to communicate what I have learned, another person cannot have this same kind of knowledge without similarly touching the tree for himself. The here-and-nowness of such knowledge, in fact, is precisely what gives it firmness and strength. The more it recedes into the distance of memory or the vagueness of second-hand communication, the less we are inclined to call it knowledge at all.

The trouble is that English lacks a word for this. We have the verbs “to appear” or “to seem,” and we have nouns on the object side such as “appearance.” But what do we call the subjective state in us that results from such appearances? Whatever we call it in English, that’s what δόξα means in Greek: the state we’re in when something appears to us a particular way. “Experience,” “observation,” and “perception” come pretty close, but they are all too general and fail to make explicit the way that δόξα is the result of something “seeming” a certain way. So perhaps the best we can do is to translate δόξα with phrases such as “appearance-based-knowledge” or “knowledge-gained-through-sensation”—or we could just translate it as doxa and leave it at that.

On the intelligible side of our initial distinction, we have the Greek word ἐπιστήμη (episteme). From this word, we have the whole branch of philosophy that we call “epistemology.” Traditionally, ἐπιστήμη has been translated as “knowledge,” and from this translation, the idea has been popularized that Plato thinks we can only have real knowledge when it comes to the Forms, denying categorically any knowledge of ordinary things. That way of putting it, however, misses the point. Plato would be the last person to deny my real experience of the beautiful maple trees. Instead, he’s simply pointing out a fundamental distinction in the way that I know those particular trees and the way that I know truths about Equality (to take our example from the last essay).

When I think about Equality, I understand certain truths about it. For example, I understand that if A is equal to B, then B must also be equal to A. That is, Equality is necessarily a reciprocal relation. I understand that if A is equal to B and B is equal to C, then A must also be equal to C. That is, Equality is necessarily a transitive relation. I understand that half of A is equal to half of B, that twice A is equal to twice B, and so on for any quantitative modification I care to make. What is more, I understand that these truths don’t just apply to one or two cases of Equality that I happen to experience, but to any case of Equality anywhere in the universe at any time. If these truths failed to apply to some particular case, it just wouldn’t be a case of Equality. And it’s not just me. I understand that any being capable of understanding Equality must also come to the same conclusions. My understanding of Equality, then, is not a seeming at all. By understanding Equality, I grasp something independent of perspective, appearance, time, or place. Hence, the kind of knowledge that I have has a kind of stability, certainty, and completeness that doxa lacks.

For now, rather than saying that Plato relegates “knowledge” to the realm of “ideas,” which is misleading at best, I suggest that we simply leave these two Greek words untranslated. With this explanation in hand, we will know that doxa refers to appearance-based-knowledge while episteme refers to intelligence-based-knowledge. We will need to divide these two categories into further distinctions as we go, but for now, we can organize what we have learned into the following chart: