Memory-based modes of presentation

To deal with memory-based modes of presentation I propose a couple of revisions to the standard criterion of difference for modes of presentation attributed to Frege. First, we need to broaden the scope of the criterion so that not merely the thoughts of a given subject at a given time may or may not involve the same way of thinking of some object, but also the thoughts of a subject at different times. Second, we need to ‘relativize’ the criterion of difference to particular subjects in particular situations. Thanks to these revisions, we can make sense of Evans’ notion of a dynamic mode of presentation that persists through time despite lower-level changes. A dynamic mode of presentation is a complex mode of presentation involving several epistemically rewarding relations to the reference successively (in contrast to composite modes of presentation, which involve several epistemically rewarding relations simultaneously). I show how this idea can be cashed out in the mental file framework, and how, in that framework, we can provide a straightforward answer to the question: when is a mode of presentation based on a memory M the same as the mode of presentation based on the perception P from which the memory derives? The answer appeals to the distinction between anchored and unanchored memories.