Course Notes are short pieces on classic papers and essays that I taught regularly, during my thirty-year career as a philosophy professor.
The central message of Sibley’s thesis is that aesthetic concepts are not ascribed by way of criteria, but require taste, discernment, and perceptiveness to apply. Beyond aesthetics, Sibley’s critique is part of a larger effort to challenge traditional conceptions of definition and by extension, formal approaches to semantics.
Sibley gives no general definition of aesthetic concepts (beyond saying that they are concepts that require taste to apply), but he does provide examples, including ‘graceful’, ‘delicate’, ‘dainty’, ‘handsome’, ‘comely’, ‘elegant’, ‘garish’, to name just a few.
Sibley also observes that we often give reasons for our ascriptions of aesthetic terms, in terms of non-aesthetic, descriptive characteristics that do not themselves require perceptiveness or taste to apply. We might say, for example, that a figure is delicate “because of its pastel shades and curving lines” or that a picture depicting a party “lacks balance because one group of figures is so far off to the left and is so brightly illuminated,” and while ‘delicacy’ and ‘lack-of balance’ are aesthetic concepts and require taste to apply, terms like ‘pastel’ and ‘brightly illuminated’ are not and do not.
Sibley’s critique begins with the point that aesthetic concepts do not admit of necessary and sufficient conditions for their application, as one might find with the concepts of, say, geometry. Having four sides of equal length and interior angles of ninety degrees are jointly necessary and sufficient for a figure to be a square, but there is no comparable set of necessary and sufficient conditions for something being delicate or witty.
Of course, few concepts admit of necessary and sufficient conditions, most being of a sort for which the relevant conditions apply more loosely. There are, for example, concepts for which there are no necessary conditions, but for which there are some number of conditions which, if they are met, would be enough. Suppose, for example, that I tell you that my cousin is intelligent, and when you ask me why I think that, I explain truthfully that he graduated summa cum laude from Princeton and was accepted to Harvard Medical school, where, as a student, he discovered a cure for diabetes. Surely, these characteristics, taken together, are sufficient for calling my cousin intelligent, despite the fact that not a single one of them is necessary. One could easily imagine a most intelligent person who did none of these things.
As Sibley correctly points out, aesthetic concepts are not even governed by conditions in this loose way. Unlike the case of applying the word ‘intelligent’, there is no list of characteristics, such that if something had them, one would have no choice but to deem it delicate or garish. As Sibley observes, one couldn’t say, “If the vase is pale pink, somewhat curving, lightly mottled, and so forth, it will be delicate, cannot but be delicate.” It may, indeed, turn out to be delicate, if one looks at it, and one may even want to say that it is delicate because of these features, but one could not predict, ahead of time, on the basis of these features, that it will be delicate.
The reason is that the characteristics that make something delicate or garish or may also be responsible for an object’s having very different qualities; qualities that may in fact be contradictory. Pale colors and gently curving contours may make a vase insipid as well as delicate, and a single object cannot be both. Bright colors may make something bold, as well as garish, but a single picture cannot have both of these aesthetic characteristics at once.
At most, then, one can say that certain non-aesthetic characteristics typically count for or against a certain aesthetic quality – pale colors typically count in favor of delicateness and against garishness, where the opposite is true, in the case of bright ones – but knowing this does not mean that we can ascribe aesthetic concepts on the basis of criteria, and without perceptiveness or taste.
This leads us in a number of different directions, towards which Sibley points with varying degrees of detail:
 Whatever the relationship is between a thing’s non-aesthetic characteristics and its aesthetic properties, it is going to lie in the particular instances of its non-aesthetic characteristics and not in the fact that it has them, generally speaking. The vase is not delicate because it is painted in pale colors, as a general matter, but because of these particular delicate colors.
 When we offer reasons for our assigning of various aesthetic characteristics, in terms of non-aesthetic, descriptive properties, we cannot be justifying our judgment, in the epistemic sense of the word, insofar as justification is inferential and inferences are always in terms of general, rather than particular characteristics. (As Allan Bloom once put it, “Everyone knows that the particular as particular escapes the grasp of reason, the form of which is the general or universal.”) Rather, what we are doing, in offering such reasons, is calling our interlocutor’s attention to general features, the particular instances of which, in this particular work, are responsible for the aesthetic characteristic in question.
 The ascription of aesthetic concepts is not possible, other than in the presence of the object or some suitably similar facsimile.
Beyond these and other implications for the practice of art criticism, Sibley’s thoughts on this subject strike me as important, insofar as they give a very clear example of an entire domain of language and practice, which by its very nature resists systematization, whether philosophical or scientific.