There are many alternative ways that a mind or brain might represent that two of its representations were of the same object or property, the 'Strawson' model, the 'duplicates' model, the 'synchrony' mode, the 'Christmas lights' model, the 'anaphor' model, and so forth. I first discuss what would constitute that a mind or brain was using one of these systems of identity marking rather than another. I then discuss devastating effects that adopting the Strawson model has on the notion that (...) there are such things as modes of presentation in thought. Next I argue that Evans' idea that there are 'dynamic Fregean thoughts' has exactly the same implications. I argue further that all of the other models of thought discussed earlier are in fact isomorphic to the Strawson model. a search for the source of these difficulties reveals the classical notion of modes of presentation as resting on two assumptions, neither of which I recommend. It depends on denying that the way the mind reacts to or understands the thoughts or ideas that it harbours has any bearing on their intentional contents. And it depends on an internalist view of thought content, in particular, on denying that the natural informational content carried or potentially carried by a thought has any bearing on its intentional content. (shrink)