 It should be noted here too that the movement from Frege and Russell toward externalist views of intentional content has been, and continues to be subject to serious detailed challenges, and has prompted development of alternative (sometimes avowedly internalist) accounts. (Consider, for example: Crane 1991, Farkas 2008, Ludwig 1996b, and Searle 1983.) And it is no easy matter even getting clear about the fundamental theses at issue—partly insofar as what it means to talk about what is “internal” to the subject, and just what is assumed about the notion of content, are often unclear. In fact, Brie Gertler (2012b) argues that the “internalism/externalism debate” is something of a mess, and there is ultimately no satisfactory univocal understanding of just what is under dispute.