Anatta, in Buddhist philosophy, the "non-self" or "absence of separate self"
Anātman (Hinduism), a similar concept in Hinduism
Open individualism, the philosophy that there exists only one numerically identical subject, who is everyone at all times, in the past, present and future.
The distinction of self from non-self, a central concept in Immunology proposed by Macfarlane Burnet
Exogenous antigen, a non-self molecule that stimulates an immune response
