"Who am I?" is an honest, deep, central question. A quick, snappy answer is problematic. Thinking about it long & deep, and concluding "I don't know" is far more honest and wiser. Isn't "Who am I?" a koan or open question?
As we mature, our paradigms (working hypotheses) re identity & worldview ideally become less fear-based, rigidly dogmatic, and more loving, & congruent with the evolution of our consciousness. However, as in most aspects of life, there are many alternatives.
There are 3 major identity styles that deal with identity-relevant questions and concerns:
1) diffuse-avoidant identity style
• reluctant to face up to & confront personal problems & decisions’
• predicts problematic qualities (eg neuroticism), coping & decisional strategies (eg disengagement), and mental health outcomes (eg depression)
2) normative identity style
• deal with identity questions & decisional situations by conforming to the prescriptions & expectations of significant others
• associated with high self-esteem & educational purpose
• associated with the tendency to be conservative, authoritarian, & racist.
3) informational identity style
• actively seek out, evaluate, & use self-relevant information
• associated with openness to experience, introspectiveness, self-reflection, & cognitive complexity
• the only form that positively predicts mature adjustment in the form of psychological hardiness, personal growth, & life purpose.
Beaumont SL. Identity styles and wisdom during emerging adulthood: Relationships with mindfulness and savoring. Identity: An International Journal of Theory and Research 2011; 11(2): 155-180.
"In most conventional psychological theory ... identity is typically defined in egoic terms. That is, a person’s sense of self is generally seen as circumscribed (ie has defined boundaries), is highly individualized, & is, for the most part, subjective. ... Within such conceptualizations, spiritual identity most often is defined as how the individual ego relates to & incorporates spirituality into its personal sense of self. ... how one experiences & integrates their sense of relationship to the transcendent into their egoic self-sense. ... 'a role-related aspect of an individual’s overall sense of ego identity' which manifests 'as a persistent sense of self that addresses ultimate questions about the nature, purpose, and meaning of life'.
In contrast, there is another view, best represented in the mystical, philosophical, & spiritual literature but now formalized most ostensibly in transpersonal theory, that argues identity may not be delimited to ego & egoic functions but rather is fundamentally spiritual in nature. From this perspective, the boundaries that demarcate the ego (ie self from not-self), are not absolute & immutable but rather are constructed, malleable, & even arbitrary, capable of being modified (eg expanded or contracted) or dissolved altogether."
MacDonald DA. "Identity and Spirituality: Conventional and Transpersonal Perspectives." International Journal of Transpersonal Studies 2009; 28(1): 86-106.
Identity, from certainly a Buddhist, but also increasingly from Western secular perspectives, is ephemeral, shifting, constantly changing, like all phenomena. And clinging to any phenomena, particularly to "the self", is considered the chief cause of suffering. To the extent that our identity is fused with self-concept ie "I am my self-concept", we suffer. Leary MR, Guadagno J. "The role of hypo-egoic self-processes in optimal functioning and subjective well-being." (Chapter 9) in: Sheldon KM, Kashdan TB, Steger MF. eds. "Designing positive psychology: Taking stock and moving forward." Oxford University Press, NY, 2011.
"A young person who both explores & commits is said to have an achieved identity status, whereas a person who does neither is said to have diffuse identity status. A person who commits without exploration has a foreclosed identity status, and a person who explores but does not commit remains in moratorium identity status." Helson R, Srivastava S. "Three paths of adult development: conservers, seekers, and achievers." J Pers Soc Psychol 2001; 80(6): 995-1010.