 Hence, it is one thing to inquire into what features of some past theories accounted for their success and quite another to ask whether these features were such that they were retained in subsequent theories of the same domain. These are two independent issues and they can be dealt with (both conceptually and historically) independently. One should start with some past theories and—bracketing the question of their replacement—try to identify, on independent grounds, the sources of their empirical success; that is, to identify those theoretical constituents of the theories that fuelled their successes. When a past theory has been, as it were, anatomised, we can then ask the independent question of whether there is any sense in which the sources of success of a past theory that the anatomy has identified are present in our current theories. It’s not, then, the case that the current theory is the common source for the identification of the successful parts of a past theory and of its truthlike parts.