The properties of Turing's famous 'universal machine' has long sustained functionalist intuitions about the nature of cognition. This paper shows that there is a logical problem with standard functionalist arguments for multiple realizability. These arguments rely essentially on Turing's powerful insights regarding computation. In addressing a possible reply to this criticism, it is further argued that functionalism is not a useful approach for understanding what it is to have a mind. In particular, it is shown that the difficulties involved in distinguishing implementation from function make multiple realizability claims untestable and uninformative. As a result, it is concluded that the role of Turing machines in philosophy of mind needs to be reconsidered.