The concept of “tacit knowledge” as the means by which individuals interpret the “rules” of social interaction occupies a central role in all the major contemporary theories of action and social structure. The major reference point for social theorists is Wittgenstein's celebrated discussion of rule-following in the Philosophical Investigations. Focusing on Giddens' incorporation of tacit knowledge and rules into his “theory of structuration”, I argue that Wittgenstein's later work is steadfastly set against the “latent cognitivism” inherent in the idea of (...) tacit knowledge and tacit rules. I also argue that the idea of tacit knowledge and tacit rules is either incoherent or explanatorily vacuous. (shrink)