The previous chapter's conclusion that minds are brains has major implications for two central
philosophical questions: what is reality, and how do we know it? These questions are interrelated, as
consideration of what things exist needs to fit with discussion of what it takes to gain knowledge
about those things. For example, an empiricist who believes that knowledge can come only through
the senses might conclude that physical objects such as lions and mountains are not real, because we
sense only features of them, not the things themselves.