by Stephen A. Butterfill
"What it is to be a mindreader? Mindreading involves identifying mental states; this requires having some model of the mental, much as identifying physical states requires having some model of the physical. And philosophical failures to characterise minds reveal that there are multiple models of the mental, much as the history of science reveals that there are multiple models of the physical. To say that someone is a mindreader therefore leaves open the question of which model of the mental she is using. Just as humans use multiple models of the physical (an expert physicist will probably leave quantum mechanics behind when putting up a garden fence in favour of a model she can more efficiently deploy), so it is likely that they use multiple models of the mental. This may matter for understanding why mindreading is sometimes but not always automatic—some models are relatively easy to acquire or apply but are limited in accuracy, others are harder to acquire and use but also more accurate. But how can we test hypotheses about which model is used in a particular task? As in the physical case, different conjectures about models of the mental can be distinguished because different models have different signature limits. In particular, one class of models, minimal models of the mental, have signature limits involving identity. Recent scientific discoveries indicate that these limits can be used to confirm conjectures about how infant and adult mindreaders model minds.