Martin Heidegger said this quote
“ Dasein *is authentically itself* in the primordial individualization of the reticent resoluteness which exacts anxiety of itself. *As something that keeps *silent*, authentic *Being*-one’s-Self is just the sort of thing that does not keep on saying ‘I’; but in its reticence it ‘*is*’ that thrown entity as which it can authentically be. The Self which the reticence of resolute existence unveils is the primordial phenomenal basis for the question as to the Being of the ‘I’. Only if we are oriented phenomenally by the meaning of the Being of the authentic potentiality-for-Being-one’s-Self are we put in a position to discuss what ontological justification there is for treating substantiality, simplicity, and personality as characteristics of Selfhood. In the prevalent way of saying “I,” it is constantly suggested that what we have in advance is a Self-Thing, persistently present-at-hand; the ontological question of the Being of the Self must turn away from any such suggestion.*Care does not need to be founded in a Self. But existentiality, as constitutive for care, provides the ontological constitution of Dasein’s Self-constancy, to which there belongs, in accordance with the full structural content of care, its Being-fallen factically into non-Self-constancy*. When fully conceived, the care-structure includes the phenomenon of Selfhood. This phenomenon is clarified by Interpreting the meaning of care; and it is as care that Dasein’s totality of Being has been defined.”―from_Being and Time_. Translated by John Macquarrie & Edward Robinson, pp. 369-370 ”