In her black and white room, Mary doesn’t know what it is like to see red. Only after undergoing an experience as of something red and hence acquainting herself with red can Mary learn what it is like. But learning what it is like to see red requires more than simply becoming acquainted with it. To be acquainted with something is to know it, but such knowledge, as we argue, is object-knowledge rather than propositional-knowledge. To know what it is like one must know an appropriate propositional answer to the question ‘what is it like?’. Despite this mismatch between object-knowledge and knowing an answer, we believe that acquaintance is crucial to Mary’s epistemic progress.
When Mary leaves her black and white room, her new knowledge tempts one to think that she must come to know a candidate answer (a coarse-grained fact) that she didn’t know in her room. Since Mary already knows all the physical facts in her room, any additional facts she might learn appear to threaten physicalism. In reply, many physicalists have been attracted to the phenomenal concept strategy according to which Mary can come to have new knowledge and hence know a new answer to the question ‘what is it like to see red?’ by entertaining a coarse-grained fact under a concept she didn’t possess in her room – Mary learns a new fine-grained fact. We believe both of these accounts of Mary’s epistemic progress are mistaken. As we argue, Mary could know every fact (coarse-grained and fine-grained) that might serve as an answer to the question ‘what is it like to see red?’ and still not know what it is like. The physical world leaves no leftover coarse-grained facts for Mary to learn and because concepts are sharable, easy to possess, and easy to introduce, there are possible situations in which Mary, while in her black and white room, has every concept that might make a fine-grained difference. In short, even when Mary is granted a great deal of factual knowledge and vast conceptual resources, she may still not know an appropriate answer to the question ‘what is it like to see red?’. But in any such situation, Mary lacks acquaintance with red and on this basis we argue that in order to know what it is like, in order for Mary to know an appropriate answer, Mary’s propositional knowledge must be appropriately related to her acquaintance with red.