Thomas Habinek
The aim of this paper is to explore the overlapping terminology and argumentation of Stoic physics and ancient aesthetic discourse, especially with respect to the color and variety of the natural world. The Stoics, like their pre-Socratic predecessors, drew heavily on visual phenomena in developing their account of a continuous, monistic universe, and in return they supplied ancient aesthetic theory with defenses against the philosophical critique of art articulated by the Platonic Socrates and various of his successors. Discussions of color and varietas (which, like poikilia in Greek can refer either to the spangling of a surface with multiple points of light or to the gradual transition from one color to another across a surface) become touchstones for philosophical disputes over the characteristics of primordial matter as well as for the physical basis, and thus reliability, of perception. In turn, the Stoics’ account of color as intrinsic to matter and their defense of stable perception of a world in flux provide philosophical grounding for artistic practices ranging from the painting technique known as lumen et umbra to aspects of Ciceronian rhetoric.
Key passages to be considered include definitions of color by Zeno (“colors are the primary configurations of matter” [Stob. Ecl. 1.16, p. 49, 8 = Pearson #78; also Aet. 1.15.6 = SVF 1.91] and “colors gloss (or highlight) matter” [Galen Hist Philos DDG 616.2]; Chrysippus’ citation of color as one of the hexeis that differentiate a given body from another [SVF 2.449 = Plut. De Stoic repugn. cp. 43, p. 1053f.]; several fragments from Aetius discussing color and tonos (Plac. 1.6.2), the lability of color (ibid.), and a biological analogy to a painter’s use of colors (Plac. 5.11.3). The significance and usage of key terms, such as skhematismos, epikhrosis, and tonos, establish the link between physical and aesthetic discourse, while a more detailed discussion of a set of passages pertaining to mixture, both as a physical problem for the Stoics and as an artistic practice (e.g. Arist. De Sensu 440b, Plut Mor. 393a, 436b, 725c; SVF 2.471, 473; Diog. Laert. 7.151; Pollux Onomasticon 7.128-9; Alex. Aphrod. De Mixt. 233.6) further illustrates the cross-fertilization between the two approaches to material reality, the Stoic-physical and the artistic-pragmatic. With respect to mixture, the Stoic discussion of krasis can be shown to parallel ancient art theorists’ account of optical fusion, that is, the creation of an apparent third color through cross-hatching in more than one pigment. For a Stoic the blurred or glistening effect of a varied surface was not an optical illusion but direct communication between the surface and the eye, and thus the basis of reliable knowledge – an epistemological defense of artistic practice that was to ramify in the Roman world and beyond.
In a related vein, the varietas encouraged by Ciceronian rhetorical theory (e.g. De Or. 3.25, 3.98, 3.216, 3.224-5) seems to have its basis in a Stoic understanding of perceptual variability as the shared ground of natural and artistic production. More generally, rhetorical color is treated by Cicero and others in the rhetorical tradition as a means through which the “matter” of a speech makes itself visible or salient and thus available for inspection, assent, and alignment. Crassus' insistence that a speech be shaped, illuminated, and varied (De Orat. 3.103) derives its force from an underlying physics that posits the constitutive force of perception and the sympathetic interaction between all parts of a continuous universe.