Is There a Naturalistic Fallacy?

Bentham: Nature has placed mankind under the governance of two sovereign masters, pain and pleasure. It is for them alone to point out what we ought to do as well as to determine what we shall do. So it commits what David Hubbe called the exact fallacy. It ties very straightforwardly what is to what ought to be. And Hume himself commits it by saying that feelings of sympathy are what the goods can be reduced to.