Final answer:
The subject of this question is the mind-body problem in philosophy, specifically the critique of John Locke's theory of personal identity. Della Rocca raises the issue of memory and its implications for personal identity.
Step-by-step explanation:
The subject of this question is the mind-body problem in philosophy. In the question, Della Rocca is critiquing John Locke's theory of personal identity. He argues that if a person cannot remember what color shirt they wore yesterday, according to Locke's theory, they would not be the same person who wore that shirt. This presents a problem for Locke's theory of personal identity.