University of Alberta Dictionary of Cognitive Science: The Formality Condition

The semantic properties of a representation are the properties it has due to its relationship with the world; properties such as being true, of being a representation of something, of saying something about some object. On the other hand, the properties that the representation has in itself, are its formal properties. Fodor (1980) defines a representation's formal properties negatively, by specifying what they are not: "Formal properties are the ones that can be specified without reference to such semantic properties as, for example, truth reference, and meaning." (p. 227) Fodor stresses that formal properties are not syntactic properties. A representation can have formal properties, and a process can operate on those formal properties, without that representation having a syntax (p 227).

For a computational theory of mind, this implies that mental processes only have access to a representation's formal properties. Computational processes do not have any access to semantic properties; that is, to a representation's relationships with the world. Thus the processes that operate on representations cannot operate on the basis of what this is a representation of, or whether it represents that thing correctly or not, but only on the character of the representation itself, its "shape" as it were. Thus the Formality Condition incurs what Putnam (1975) calls Methodological Solipsism.

"If mental processes are formal, then they have access only to the formal properties of such representations of the environment as the senses provide. Hence, they have no access to the semantic properties of such representations, including the property of being true, of having referents, or, indeed, the property of being representations of the environment." (Fodor (1980), p 231, Fodor's emphasis)

The solution to this methodological solipsism is to pair a computational psychology with what Fodor calls a naturalistic psychology: a theory of the relations between representations and the world, which fix the semantic interpretations of representations' formal properties. (p 233) That is, a representation's formal properties must somehow mirror the representation's semantic properties, so that operations can operate on formal properties which can at least be interpreted as saying something about some part of the world (whether or not that interpretation is correct, true, appropriate, etc.).

References:

Fodor, J. (1980). Methodological Solipsism Considered as a Research Strategy in Cognitive Psychology. In Representations (pp. 225-253). Cambridge, Massachusetts: MIT Press. A Bradford Book.
Putnam, H. (1975). The Meaning of Meaning. In K. Gunderson (Ed.), Minnesota Studies in the Philosophy of Science (pp. 131-193). Minneapolis: University of Minnesota Press.

(Revised April 2010)