In philosophy, the self is an individual's own being, knowledge, and values, and the relationship between these attributes.
The first-person perspective distinguishes selfhood from personal identity. Whereas "identity" is (literally) sameness and may involve categorization and labeling,selfhood implies a first-person perspective and suggests potential uniqueness. Conversely, "person" is used as a third-person reference. Personal identity can be impaired in late-stage Alzheimer's disease and in other neurodegenerative diseases. Finally, the self is distinguishable from "others". Including the distinction between sameness and otherness, the self versus other is a research topic in contemporary philosophy and contemporary phenomenology (see also psychological phenomenology), psychology, psychiatry, neurology, and neuroscience.