Lecture 6 — The species of color

Accordingly, what causes light in the air may be present in the transparent. But it may also not be present in it; instead, its privation may be. Thus, just as in that case the one is light and the other darkness, so white and black are caused in bodies.

But we must speak about the other colors, dividing the number of ways they might come to be. It can happen that, if white and black are placed beside one another, each of them invisible because of their smallness, what is made up of both thus becomes visible. It is seen neither as white nor as black. But because it necessarily has some color, and neither of these is possible, it necessarily is mixed, and is another species of color. Thus one can admit of more colors than white and black.

But many are in a proportion, for they can be put together in the proportion of three to two, and of three to four, and according to other numbers. But some are together in no proportion at all, but in an incommensurable more and less.

So it must be the same as in harmonies: the most well-proportioned colors are those based on numbers, as in the case of harmonies, and these seem to be the most pleasant of colors, for instance scarlet and purple. But such are few, due to the same cause harmonies are also few. And the other colors are those not based on numbers.

Or, all colors are ordered on the basis of numbers, but some are disordered when they are not pure, and they become such because they are not based on number. This is one way for the generation of colors.

Another one is that they appear through one another, in the way that painters sometimes place one color over another, more manifest one, as they do when they wish to make something appear to be in water or in air. And in this way the sun of itself appears white, but through fog and smoke it appears purple.

And there will also be many colors in the same way as described above: there will be a proportion of those on the surface to those in the depth; but some are not in any proportion at all.

95. Accordingly, what causes light in the air (439b14). After the Philosopher has shown what color is, here he proceeds to distinguish the species of colors.

First, with respect to extreme colors;

second, with respect to intermediate colors, where he says but we must speak about the other colors (439b18; [96]).

Now the differences by which species are distinguished should divide a genus per se, not accidentally, as is clear in Metaphysics 7. (Aristotle, Metaphysics 7.12, 1038a9–26; cf. Aquinas, Commentary on Metaphysics, bk. 7, lect. 12, nn. 1542–65.) Therefore, he concludes to the variety of species of color from the very nature of color, which he explained through the definition given above. (Cf. ch. 5, nn. 87–93.)

It is established from the foregoing that the subject of color is the transparent at its limit in limited bodies. (Cf. ch. 5, nn. 90–92.) But the proper actuality of the transparent as such is light, the presence of which in the unlimited transparent, for instance air, causes light, but the absence of which causes darkness. Therefore, what causes light in the air may be present on the limit of the transparent belonging to limited bodies, where it will cause the color white; and the color black will be caused by its absence.

This is not to be understood as if there were no light in the color black, for thus black would not be contrary to white, since it would not participate in the same nature; rather, it would be a pure privation, like darkness. Black is said to be caused by absence of light because it of all colors has the least light, as white has the most; for contraries are things that stand farthest apart in the same genus, as is said in Metaphysics 10. (Aristotle, Metaphysics 10.4, 1055a4–10; cf. Aquinas, Commentary on Metaphysics, bk. 10, lect. 5, nn. 2023–35.)

96. Then, when he says but we must speak about the other colors (439b18), he proceeds to distinguish intermediate colors.

This is divided into two parts.

In the first, he presents certain ways for the generation and distinction of intermediate colors not according to their existence, but according to their appearance.

Second, he gives the true generation of intermediate colors according to their nature, where he says but there is mixture of bodies not only (440a31; [113]).

On the first point, he does two things.

First, he presents two ways for the generation and distinction of intermediate colors according to appearance.

Second, he compares those ways to one another, where he says but to say, like the ancients (440a15; [105]).

The first part is divided into two according to the two ways he presents;

the second part begins where he says another one is that they appear (440a7; [103]).

On the first point, he does two things.

First, he presents the generation of intermediate colors.

Second, where he says but many are in a proportion (439b27; [100]), he gives their distinction.

97. Accordingly, he first says that since the extreme colors have been discussed, (Cf. cc. 5–6, nn. 80–95.) we must speak about the other colors—that is, the intermediate ones—distinguishing the number of ways they might be generated.

Let it be supposed, then, that there is something invisible because of its smallness. Thus it can happen that if two small bodies, invisible because of their smallness, are placed next to one another, one of them being black and the other white, what is composed of both can be seen, because of the greater quantity. Now everything that is seen in bodies of this kind is seen according to some color. But the whole is seen neither as white nor as black, because both what is white in it and what is black have been assumed to be invisible because of their smallness. Hence it is necessarily seen as a color mixed from both, as it were, so that thus there is another species of color besides white and black. From this it is clear that one can admit of more colors than black and white.

98. Then, when he says but many are in a proportion (439b27; [100]), he gives the distinction of intermediate colors.

First, he assigns the cause of distinction of intermediate colors to various proportions of black and white.

Second, he gives the cause why some intermediate colors are pleasant and some not, where he says so it must be the same as in harmonies (439b30; [101]).

On the first point it must be considered that, as the Philosopher teaches in Metaphysics 10, the notion (ratio) of measure is found first in numbers, and second in continuous quantities. (Aristotle, Metaphysics 10.1, 1052b18–1053b8; cf. 5.6, 1016b17–31; cf. Aquinas, Commentary on Metaphysics, bk. 10, lect. 2, nn. 1937–60.) From the latter it is transferred even to qualities, insofar as among them one quality can be more than another, whether by way of intension, as one thing is said to be “whiter” than something else, or by way of extension, as whiteness on a bigger surface is said to be “bigger.”

Now because proportion is a relation of quantities to one another, wherever one speaks of quantity in any sense, one can also speak of proportion.

First, in the case of numbers, which are all commensurable with one another, for they all share in the first measure that is unity.

99. And there are various proportions of numbers according as various numbers are related to one another: the proportion of three to two, which is called “sesquialteral,” is different from that of four to three, which is called “sesquitertial.”

But because continuous quantities cannot be resolved into something indivisible as numbers are into unity, not all continuous quantities are necessarily commensurable with one another; rather, one can find some in which one is more than another but they have no one common measure. However, whatever continuous quantities are proportioned to one another according to the proportion of number to number do have one common measure: for instance, if one is three cubits long and another four, both are measured by the cubit.

100. In this way too, there can be more and less among qualities either according to a numerical proportion or according to an incommensurable difference.

And that is what he says: that there can be many intermediate colors in various proportions. For it can happen that white is juxtaposed to black in the proportion of two to three, or of three to four, or of any other numbers; or again, in no numerical proportion, but only in an incommensurable more and less.

101. Then, when he says so it must be the same as in harmonies (439b30), he shows why some colors are pleasant and some not.

He gives two reasons for this.

He gives the second where he says or, all colors are ordered on the basis of numbers (440a3; [102]).

Accordingly, he first says that, given that intermediate colors are distinguished according to various proportions of white and black, it must be the same with intermediate colors as it is with harmonies, which are caused according to a proportion between a low and a high tone. For just as in the case of harmonies, the most well proportioned and pleasant are those based on numbers, as the octave is in the proportion of two to one, and the fifth in the proportion of three to two; so also in the case of colors, those based on numerical proportion are the most well-proportioned. And these also seem to be most pleasant, for example scarlet and purple, that is, red and dark red. And just as pleasant harmonies are few, so also such colors are few. But other colors, those that are not pleasant, are not established in numerical proportion.

102. Then, when he says or, all colors are ordered on the basis of numbers (440a3), he gives another reason why some colors are pleasant and some not.

He says that all species of colors can be said to be ordered according to numbers. And he can make this change because now there will be a different species of color not merely if there is difference according to more and less, but only when there is more and less according to a numerical proportion. If this is supposed, it will follow that these same colors are disordered when they are not “pure,” that is, if there is more white than black according to one proportion in one part, but according to another numerical proportion in another part, and this confusedly and without order. And so, because there will not be the same numerical proportion throughout the whole, it will follow that these colors will be disordered and unpleasant.

Finally he concludes that this is one way of generation of intermediate colors.

103. Then, when he says another one is that they appear through one another (440a7), he presents the second way of generation of intermediate colors.

First, he explains the generation of intermediate colors;

second their distinction, where he says and there will also be many colors (440a12; [104]).

Accordingly, he first says that, besides the above-mentioned way, there is one other way of generation of intermediate colors according to appearance: by one of the colors appearing through another so that from two colors there results an appearance of an intermediate color. And he gives two examples.

The first is taken from artificial things. Painters sometimes place one color over another, in such a way that the more manifest—that is, the stronger and more lively—color is placed underneath: otherwise, if the weaker one were placed underneath, it would not appear at all. And they do this in particular when they wish to make something appear in their picture as if it were in air or in water, for instance when they paint fish swimming in the sea: for then they put over the stronger color of the fish some weaker color as the color of the water.

The other example is taken from natural things. The sun of itself appears white because of the brightness of light, but when it is seen by us through a medium of fog, or smoke released from dry bodies, then it seems purple—that is, ruddy. Thus it is clear that what is in itself one color, when it is seen through another color, causes the appearance of a third color: for smoke in itself is not red, but rather black.

104. Then, when he says and there will also be many colors (440a12), he gives the explanation of the distinction of colors according to this way.

He says that intermediate colors are multiplied, in this way of generating them, in the same way as they are in the above-mentioned way, namely according to different proportions: one can take a proportion of the color placed underneath—which he describes as “in the depth”—to the color placed above—which he describes as “on the surface.” However, some colors placed above and below one another are not in a proportion—that is, a numerical one—and so unpleasant colors are caused, as was also said above.