This article defends the decision to retain usage of trade, course of performance, and course of dealing in the revision of Article 1 of the Uniform Commercial Code. The article responds to recent neoformalist criticisms of the incorporation approach and offers a theoretical justification. Usage of trade and course of dealing should be understood as part of the parties' language, following Wittgenstein's understanding of language. Course of performance, which presents a weaker case in terms of language, should be understood as a legal formality, following Fuller's explanation of formalities. Thus understood, custom and conduct can be as important as written documents in determining the parties' assent. Ignoring custom and conduct risks subordinating the parties' assent as the central norm of contractual liability.
Snyder, David, "Language and Formalities in Commercial Contracts: A Defense of Custom and Conduct" (2001). Articles in Law Reviews & Other Academic Journals. 777.