"A rose by any other name..."
René Descartes, in the “First Meditation,” of his Meditations On First Philosophy (1641), has this to say about painters and philosophy:
“For, as a matter of fact, painters, even when they study with the greatest skill to represent sirens and satyrs by forms the most strange and extraordinary, cannot give them natures which are entirely new, but merely make a certain medley of the members of different animals; or if their imagination is extravagant enough to invent something so novel that nothing similar has ever before been seen, and that then their work represents a thing purely fictitious and absolutely false, it is certain all the same that the colors of which this is composed are necessarily real. And for the same reason, although these general things, to wit, [a body], eyes, a head, hands, and such like, may be imaginary, we are bound at the same time to confess that there are at least some other objects yet more simple and more universal, which are real and true; and of these just in the same way as with certain real colors, all these images of things which dwell in our thoughts, whether true and real or false and fantastic, are formed.”
Philosophy is for me, as it is for Descartes, a meditation. When, however, a philosopher uses art for rhetorical effect—the art of painting, specifically—as Descartes does here, my attention snaps from meditation to practical matters. I am a painter. Descartes' analogy may be taken as a figure of speech by readers who are not painters. We painters take every allusion to painting literally in one sense or another -no matter how fine the point.
Before addressing what I take to be the point of Descartes' allusion, let's recall the historical fact of Descartes' residence in the Netherlands. It was first, and foremost, the Protestant social order of the Dutch Republic which made the philosopher feel at home. It was as far ideologically, as well as geographically, from the reaches of the Spanish Inquisition as Descartes could get. He enjoyed his Dutch hosts' respect for his intellectual privacy.
Incidentally, by making his residence the Netherlands, Descartes may have developed a taste for the art of the “Dutch Masters” school of painters. Look at the characteristic Portrait of Descartes (1649), by Frans Hals, now in the National Gallery of Denmark. Descartes lived in Leiden (birthplace of Rembrandt). A diligent historian might discover many possible meetings between Descartes and representatives of the Dutch Master School, including artists, merchants (dealers), and connoisseurs.
Descartes' trope on painting, therefore, is justified by circumstances. Who knows but that Descartes watched painters at work in their studios, mixing colors, a mixed “medley,” as he puts it, of diverse paints? And, as Descartes would have noted, the entire painting is thus “composed” of simpler, more elementary components—none of which might be considered artistic in itself—but each and all constituents of the finished whole.
And in so reflecting on the painter's art, Descartes addresses the Scholastic argument over predicate and subject. The importance of this bedrock debate cannot be over-estimated. It crosses cultural boundaries and historical epochs. It is the essence of Phenomenology, as we know it today, and the reason Descartes is considered its founder.
Consider a blue rose. It may look blue, but in fact, it is an ordinary white rose given a false blue tint by art or, if you prefer, by artifice. As a more straightforward example, consider a natural red rose. What, now, if the red tint is taken away? A colorless rose may said to exist, but I can't imagine what it looks like, much less point to an example -filtered, painted, or otherwise represented to the senses.
The colors of most objects are a mixture of a few, primary, colors. Blue, Red, and Yellow are the primary colors. They cannot be reduced to more elementary “hues.” A given mixture—of green, orange, or purple—may be analyzed again into its constituent, primary colors, Blue, Red, or Yellow. Green is analyzable into blue and yellow. It is mixed by combining blue and yellow paint. The constituent colors are, thus, "primary." They, alone, cannot be mixed from more primary colors.
As for the reality of the white rose which has had its “whiteness” withdrawn, it is as invisible to the eye—as to the mind—as any rose of any color from which color is withdrawn. White is a special case because, as a “color,” it has unique properties. It contains all colors, as physics demonstrates by the refraction of white light into the colors of the rainbow. You could call white the generative color. All other colors descend from white.
From the foregoing argument, Descartes postulates (but does not prove), the existence of a limited number of primary predicates, from which the infinitude of combinations thereof are generated. My only reservation is that Descartes takes "painting" for one such simpler thing—a mere rhetorical trope—upon which he erects his phenomenological edifice. Descartes has it backwards. Perception (phenomenon) is the simpler thing, from which the art of painting is derived, in ontological order.
Returning to metaphysics, if everything is a "medley" of a limited number of simpler attributes (Aristotle calls them substance), what, we might ask, is the simplest substance of all? Many philosophers deny there is such a thing, but I submit that the simplest entity (un-predicated substance) is being-as-such, that which everything has in common with everything else. One might venture to nominate this hypothetical primary being (as Aristotle does), as "first cause," or even (as Descartes does), as God.