Final answer:
Hume criticized Descartes' and Locke's views on personal identity, disputing substance dualism and the theory of psychological continuity. He believed our changing thoughts and perceptions prevent a stable identity, and questioned the reliability of memory as a basis for identity.
Step-by-step explanation:
David Hume criticized the views of Descartes and Locke on personal identity because he saw fundamental issues in their philosophies. While Descartes was a substance dualist, asserting that the mind and body were two separate entities, Hume rejected the notion that we could have knowledge of the self as a single, unchanged and identifiable entity over time. In contrast to Locke, who believed in psychological continuity and that consciousness and memory defined personal identity, Hume argued that our thoughts and perceptions are constantly changing and thus cannot provide a stable basis for identity.
Hume brought a skeptical view to the discussions about personal identity. He proposed that our impressions form the basis of our thoughts and that reason alone does not lead to certain knowledge. In particular, he challenged Locke's theory by questioning the reliability of memory and pointing out that our perceptions are fleeting and subject to change, making it impossible to establish a permanent identity over time.