Conventionality and Perspective

Lcortardo, Vol. 9, pp. 217-218. Pergamon Press 1976. Printed in Great Britain CONVENTIONALITY AND PERSPECTIVE Marcus B. Hester* In some discussions of perspective in paintings, especially Nelson Goodman’s version, I think that there is a lack of distinction between conventional, based on conventionand merely conventional. Goodman refers to ‘the conventionality of perspective’ and then denies that perspective obeys the laws of optics [I]. His argument moves from the legitimate claim that perspective is conventional to the misleading claim that perspective is based on convention or is merely conventional. 1. Kinds of Conventionality Conventionalrefers to something that involves an end to be achieved and the achievement is subject to scientific verification. Thus, there are conventional automobile tires, wars, training methods for sports, methods for learning to play the clarinet, hypotheses about the quantity of matter in an expanding universe and, an example especially useful for my argument, conventional lenses used in photography. The term unconventional is used when some innovation challenges current conventional practice. Based on conventionrefers to the origin of a practice. It means that the reason for the practice has been forgotten, it persists because of social inertia. The practice is not necessarily subject to condemnation. For example, eating with knives or forks is based on convention. Mere convention or merely conventional refers to a practice that persists solely because of social inertia and good reasons can be given against the practice. Capital punishment can be said to be merely conventional. To say that a precise system of perspective based on the physics of optics, such as that developed during the Renaissance, is conventional does not suggest that it is either inaccurate or not based on optics. (I shall indicate below the evidence for saying that the system of perspective was based on the physics of optics.) But to say that this system of perspective is based on convention or is merely conventional is ambiguous. Based on convention or merely conventional can mean: (1) The use of the system of perspective is based on convention or is merely conventional because of habit. There are two possible reasons for attacking the habitual use of a system. Habituation can stand in the way of the use of a proposed optically more precise unconventional system, if precision is desired. If optical precision is not of interest, habit can block the rejection of all systems of perspective. (2) The system itself is merely conventional or based on convention in the sense either that it is imprecise or that there exists a more precise system that is not habitually used. Goodman chooses the second sense. He denies that * Dept. of Philosophy, Box 7332, Wake Forest University , Winston-Salem, NC 27109, U.S.A. (Received 14 Oct. 1974.) Renaissance perspective is precise and that it is based on optics, and he implies that the Egyptian system is just as precise [I, p. 371. The system of perspective developed during the Renaissance was not used then or later by those artists who did not highly value aesthetically the optical precision of the system. Goodman confuses the habitual use of a system with the question of how precise a system is. He is taken in by the ambiguity of the terms mere convention and based on convention and, unfortunately, he chose the wrong ambiguous term, based on convention, to deny the optical base of Renaissance perspective. Fortunately, some painters, critics and aestheticians engaged in the dispute over Renaissance perspective have emphasized the first sense of the ambiguity, habit. 2. Systems of Perspective A 50 mm lens for a 35 mm camera is a conventional lens and habituated use of the lens is based on convention . But the image projected by that lens is, of course, not based on convention. The image is a natural phenomenon. And, of course, technological questions about how to grind lenses, what to coat them with, etc., are not questions to which the answers are based on convention. To apply the term merely conventional to a lens system artificially and misleadingly shuts o f f the full range of optical and aesthetic questions that one may ask concerning the qualities of a 50 mm lens. There are a number of very...