She has also written on 17th century (Western) philosophy, especially John Locke and René Descartes.
Her dissertation, The Role of Necessity in Empirical Knowledge, was written under the supervision of John McDowell.
Nagel also argues, building on suggestions made by Timothy Williamson, that knowledge is a mental state.
[11] Nagel considers classic questions, including about skepticism, rationalism, and empiricism, as well as more contemporary concerns, such as whether Wikipedia, "where most articles have multiple and anonymous authors", can be a reliable source of knowledge.
She argues that human beings have a strong evolved capacity to identify knowledge, but in order to ensure flexibility in our exercise of this capacity, we engage in strategic mapping of others 'epistemic territory': the domains in which they enjoy knowledge.