I take it that computational processes are both symbolic and formal. They are symbolic because they are defined over representations, and they are formal because they apply to representations, in virtue of (roughly) the syntax of the representations.
Jerry Alan Fodor (b. 1935), U.S. professor of philosophy (Rutgers, formerly City University of) New York, MIT). "Methodological Solipsism Considered as a Research Strategy in Cognitive Psychology," p. 64, The Behavioral and Brain Sciences III, 1 (March 1980): 63-109.