The Making of Practical Optics Mathematical Practitioners’ Appropriation of Optical Knowledge between Theory and Practice

The discussion of the differing practices of mathematical practitioners’ appropriation of the optical tradition in this essay brings out a variety among mathematical practitioners and within the tradition of practical mathematics. This diversity is difficult to grasp in accounts of practical mathematics which oppose theory and practice as mutually exclusive categories. Comparing the optical projects of two geographically and socially differentiated mathematicians, the Venetian physician and mathematician Ettore Ausonio and the English town councilman and volunteer gunner, William Bourne , this essay argues that mathematical practitioners’ appropriation of optical knowledge depended upon the complexities of personal and local contexts, such as the perception of patronage opportunities. Notwithstanding the cognitive similarities of their optical projects, the balance of theory and practice is different in the presentation of their shared knowledge. Ausonio’ s practical optics, which aimed at the design of an instrument by offering a theoric, is contrasted with Bourne’ s project for the making of a telescope, which lacked any attempt at a theoric. The essay shows that, rather than as an established category, practical optics should be understood as the result of a construction by Renaissance mathematical practitioners’ appropriations of the perspectivist optical tradition.