The Sun and the Good
In the Republic Plato offers the “Simile of the Sun”, comparing the Good to the Sun. The analogy has prima facieappeal, but what Plato does with it is far from obvious or even intelligible. He writes: “Then what gives the objects of knowledge their truth and the knower’s mind the power of knowing is the form of the good. It is the cause of knowledge and truth, and you will be right to think of it as being itself known, and yet as being something other than, and even more splendid than, knowledge and truth, splendid as they are.” (Part Seven, Book Six, Section 5) On the face of it this says that the moral good is the cause of truth (the “being and reality” of objects, as he goes on to say) and also the cause of the faculty of knowledge. The moral good is what brings reality and knowledge into existence: the abstract form of the good is the origin of the universe and our ability to know about it. This sounds like a cosmological theory: the good does the kind of thing that the big bang is supposed to do. The analogy with the sun is thus that the sun is the source of growth and light, bringing visibility to objects and the power of sight to our eyes. The good enables reality, truth, and knowledge, as the sun enables sight and knowledge based on sight. I think we do well to drop the cosmological import of Plato’s theory and focus instead on the relationship between the good and knowledge. I don’t know what could be meant by saying that the form of the good is the cause of reality and truth, i.e. planets, mountains, oceans, etc. But I can see a point in saying that there is a deep connection between the good and the search for knowledge, as well as knowledge itself. For knowledge is a good thing and the search for it needs to be guided by normative principles: our epistemic endeavors need to be informed by an awareness of value—the value of knowledge and the value of the intellectual virtues. We might even claim that knowledge of the good is logically prior to knowledge of other kinds in that without it we would have no reason seek knowledge or value it. Why have knowledge of geography and physics unless there is value in having such knowledge—unless it is a good thing to know about such matters? We therefore need to apprehend the form of the good before we can apprehend other forms, to put it Plato’s way. Knowledge of the good is thus the source of all knowledge, its raison det’re. We need other inputs, to be sure, but knowledge of the good is essential to the enterprise of knowing in general. All epistemic engagement is normative engagement, as we might put it today. We might not agree with this claim, but at least we can see the point of it.
There is also a more ambitious claim that might be read into Plato’s words: knowledge is a species of goodness. Let me put it this way: truth and beauty are types of good and the good is woven into them. Truth is the good truth-value and beauty is the good way to look. We start off with an undifferentiated concept of the good, a term of commendation or even love, and then we specialize this to the epistemic and the aesthetic. Since truth is the essence of knowledge, we can view knowledge as one manifestation of the form of the good: it is the good as it exists in the realm of belief (“good opinion”). Using Platonic language (and borrowing from Frege), we can say that the True is one species of the Good, as the Beautiful is another species. Truth is what Goodness becomes when it attaches to the world of belief, as Beauty is what Goodness becomes when it attaches to the world of the senses. Thus we can construct a metaphysical picture that fits Plato’s general conception: truth and beauty derive from goodness, being special cases of it. In this sense the form of the good is the source of knowledge and beauty—easy to see in the latter case, but also evident on reflection in the former case. The basic thing is the good with truth and beauty growing out of it. So, at any rate, we might attempt to reconstruct Plato’s baffling statements. He does speak of knowledge and truth (he says nothing about beauty in this section of the Republic) as being “like the good”, and this fits with the metaphysical picture just sketched. He insists, however, that the good is not identical to knowledge and truth, being “superior to it [the reality of objects] in dignity and power”.
But how does this relate to morality and the Simile of the Sun? How does this rarified conception of the good connect with right action and ordinary moral thought? And how does it develop that promising analogy of the good to the sun? The only answer I can see to the former question is that the good is primarily the business of thought not action, knowledge not will. We need to bring normative ideas to bear when pursuing knowledge in general but particularly when pursuing moral knowledge: clear disciplined informed thinking is essential to moral judgment. So we need a firm grip on the form of the good when thinking morally: that is, we need to exercise the intellectual virtues. Moral psychology is in the first instance concerned with knowledge, perception, perceptiveness, attention to detail, etc.; it is not all about what I should do next, i.e. conduct. When your moral beliefs are true your action will be right. The will follows the intellect. Reason dictates action. So we can see why cognition of the good is linked to moral psychology for Plato: right action is just one manifestation of our cognitive connection to the good, i.e. our moral thinking. This is very Platonic: the world of forms, especially the form of the Good, is integral to all sound thinking and acting. The human soul exists in two planes: the abstract pure world of forms and the grubby empirical world of concrete particulars. This is why mathematics is so emblematic for Plato. Plato has a very inclusive conception of the good, not limited to everyday duties and political questions; still it is closely bound up with the practical and everyday. The good is “up there”, but also “down here”.
As to the sun, I propose to leave Plato’s text behind now and pursue the question more generally: how are goodness and the sun similar to each other? What kind of resemblance exists between the two? The sun is a large star existing many millions of miles from us, fiery, spherical, physical, and violent—how is that like the good? Not very like, on the face of it: the good is none of those things. We might note that the sun allows for knowledge by sending light (“a precious thing”, as Plato calls it), as the good allows for knowledge by entering into it and regulating it. So there is an epistemic analogy: both conduce to knowledge and truth. If there were no sun, our knowledge would be very limited; and if there were no value, knowledge would have no point—ignorance would be entirely acceptable. Second, the sun provides warmth and sustenance (photosynthesis and so on) and we might suppose that the good provides spiritual warmth and sustenance (it feeds the soul). If there were no such thing as the good, life would be empty and the soul bereft. The sun is good and the good is also good. But does it end there—is there any further substance to the analogy? There is plenty of disanalogy: the good doesn’t rise and set, doesn’t burn us when we are out in it for too long, isn’t round, isn’t bright, isn’t something existing in space, isn’t physical, isn’t destined to burn itself out, doesn’t hurt our eyes, and doesn’t participate in eclipses. It is true that Plato held that we can’t gaze at the good just as we can’t gaze at the sun, but this is hard to make sense of: is the exceptionally good person always screwing up his or her mind’s eye? How could goodness be blinding? But there may be other analogies that are more promising. The way to approach this question is to consider other possible similes to see whether they can do better. To this end I will consider the Simile of the Tablet: the good is like a piece of stone or wax or paper with writing on it (think of Moses with the Ten Commandments inscribed on a rock). In the Judeo-Christian tradition this has been thought to be a rather good way to think about the good: a set of inscriptions prohibiting some things and commending others. The physical embodiment of these inscriptions is not supposed of any value in itself; it doesn’t do us any good. The inscribed tablet is also man-made and man-sized. It represents the good as a set of laws—a legislative document (perhaps viewed as sacred). But the sun is something very different: large-scale, not man-made, beneficial, enabling, magnificent, and beautiful. We have a quite different attitude towards the sun than we have towards a stone: it evokes awe, gratitude, wonder, and love. It is part of nature not a human artifact, a shining pervasive presence, nothing like a grim little chunk of rock. It has splendor, iridescence, gravitas. Plato’s analogy thus encourages quite different attitudes towards the good than those encouraged by the tablet analogy—arguably healthier attitudes. Second, the sun has a unity not possessed by the tablet and its list of directives. The Ten Commandments are just a series of unconnected imperatives (they could have been written on separate pieces of rock), but the sun is a manifest unity. Doesn’t this answer to our intuitive sense that the good is an organic whole? Hence we have the singular “the Good” and not the plural “the Ten Commandments”. I grant that this sense of unity may not exist in all our hearts, so steeped are we in the Judeo-Christian tradition, but maybe it still survives in vestigial form. Remember the Unity of the Virtues and other monistic moral doctrines (the categorical imperative and utilitarianism). It feels apt to compare the good to the unified sun: large and capacious but also all one. There are not many forms of the good, as if “the good” were a definite description lacking unique reference; we intuitively apprehend it as a single thing—the form of the good. The comparison with the sun nicely captures this sense of unity, clearly important to Plato.
Now there is the question of thinghood: is the good a thing? This might be deemed a category mistake, but let’s not dismiss it so quickly. Space and time are things, so why not the good? What is the alternative? Presumably the idea that the good is a quality (or possibly a predicate): in matters of ontology we should categorize the good as something expressed by an adjective not a noun, as something that objects instantiate. But why insist on that? We find it perfectly natural to speak the good as if we are speaking of a thing; we may say that goodness is what we strive for; and we make predications of it, as in “The good is the highest value”. It is a merit of the sun simile that it captures this sense of thinghood so natural to Plato. Does this thing have parts? Now that seems to be stretching it: the sun has parts (it is a geometric object), but what would the parts of the good be? I don’t mean the set of good things; I mean goodness itself. The good seems indivisible, not an assemblage of parts. Is it homogeneous? Again, the question seems misguided: it is neither homogeneous nor heterogeneous (the sun might be hotter in some places than others). Iris Murdoch remarks that the Good (which she does not jib at reifying) is rather mysterious, so we might not know the answer to such ontological questions; but it seems wrong to transfer too much from the physical realm into the realm of the good. Is the good a person? The temptation to identify it with God certainly exists, but is not succumbed to by Plato, and I think it is a virtue of the sun analogy that this idea is resisted: the sun is not a person (despite sometimes being regarded as a god). The good is an impersonal entity like the sun—a part of nature in the broadest sense. The good is. The good is like a huge glowing force, always around us, always making itself felt. Is it far away from us like the sun? We feel goodness to exist in our vicinity, here on earth, not 93 million miles away—isn’t this a significant disanalogy? But actually the sun is all around us here on earth, because its light is (and its warmth): the sun doesn’t end at its conventional boundary but reaches out across space. When you feel its rays you feel the sun—the extended sun, as we might say. The sun analogy allows us to capture the transcendence of the good as well as its close proximity: maybe the form itself exists somewhere Platonically remote, but its effects are right next to us. Similarly, the sun exists millions of miles away, but its effects are right here: it is remote yet proximate (the tablet is neither remote nor proximate, just somewhere nearby). The sun is remotely majestic as well as intimately personal, just as the good is (recall Kant’s comment about the starry heavens and the moral law). The sun has just the right size and distance and up-closeness to resemble the good—and the same dreamy insubstantial glow. If the good assumed celestial shape, it would look like the sun. Shakespeare was onto something when he wrote, “Juliet is the sun”: she is the living embodiment of the good.
We are right to fear the good as well as love it: for it stands as a constant rebuke to our imperfection. It makes us aware of our failings and frailty, our miserable fallenness. We are also right to fear the sun as well as love it: that thing can burn you. We must not fly too close to the sun. We must respect its power. The good may warm us, soothe us, keep us in good spirits, but it can also sear us, torment us, and even drive us to despair. The moral life can be a hard life, an unforgiving life. We are ambivalent towards the good as we are ambivalent towards the sun (that relentless glare). The good is not like the moon in this respect (Plato didn’t offer the Simile of the Moon): the moon isn’t a dangerous painful thing as well as a benign thing. The sun better captures our complex attitudes towards the good: admiration and worship combined with resentment and rebellion. We don’t want to have to obey the sun, over which we have no control: we don’t want to put on the sunscreen or shield our eyes or wait for the sun rise—as we don’t want to be judged by the good, fall short of it, look shabby in comparison. Sometimes we wish it would just go away, or hide itself behind a cloud. It is unrelentingly present.
Does the good have a nucleus, a center? The sun does, where it is presumably even hotter; its surface is not quite as intense or pure. It has often been supposed that the good has such a nucleus: Plato took it to be mathematics while others have favored art or literature or science or religion or ordinary good deeds. There is a core of super-hot morality, the place where the good is most alive. I don’t think the idea is absurd and the sun analogy helps us to formulate it (there is a reason Plato loved similes and allegories). One might be a nuclear moralist intent on one sphere of that vast terrain, convinced that this is where the good is at its purest. Philosophy might even be this core (but look at the moral condition of the average philosopher). And what is it that surrounds morality—that lies outside of its solar edges? Many things: pleasure, dead matter, competition, animal love, the physical universe, time, etc. The good has an inside and an outside, an extension. It is not all-inclusive. We can represent its extension as a sphere, just as the sun is a sphere: some things lie within it and some lie outside, with some more central than others. It is not so much that it is a sphere but rather that it can be helpful to think of it this way. That was the purpose of Plato’s analogies: they function as aids to thought and maybe as guides to practice.The Simile of the Sun seems a like a useful way to think about something maddeningly elusive and troublingly abstract. The struggling intellect sometimes needs sensory help; the sun analogy is a natural way to try to come to grips with our faltering attempts to understand the good. It allows us to form an image of the good.
 I wrote this paper after reading Iris Murdoch’s The Sovereignty of Good (1970). In this book she strives to articulate a conception of the Good that differs from that of later post-Kantian moral philosophy. This conception treats the Good as a reality unto itself by no means equivalent to human acts of will (or even divine acts). I am using this background in order to discuss Plato’s Simile of the Sun (which Murdoch briefly mentions). What I say here will not seem compelling (or even intelligible) without some acquaintance with Murdoch’s book. Both of us could say that we are trying to take the Good seriously and not dismiss it as airy mystical nonsense.
 “A genuine mysteriousness attaches to the idea of goodness and the Good. This is a mystery with several aspects.” (96) “We do not and probably cannot know, conceptualize, what it is like in the center [of moral goodness]”. (97)
 The analogy of the cave stands in an interesting relation to that of the sun. In the cave there is an absence of sun so that genuine knowledge is not obtainable. By analogy there is no good in the cave, i.e. that which enables real knowledge. The sun exists outside the cave, so the man who escapes the cave comes into contact with the good, making knowledge possible. So the two analogies slot together: the sun gives knowledge and its absence prevents it; the good gives knowledge and in its absence there is only ignorance. Being outside or inside the cave corresponds to acquaintance with the good or lack of acquaintance with it, and hence with knowledge or ignorance.