ググれば用例も見つかる。

Martin Buber's I and Thou: Practicing Living Dialogue (2003):
"This happens, for instance, in the common Hindu and Buddhist
logical paradox: I am I and Thou art I."

Qtd. in A. L. Epstein, Ethos and Identity: Three Studies
in Ethnicity (1978): "If I am I, simply because I am I,
and thou art thou simply because thou art thou, then I am
I and thou art thou."

James Jackson Jarves, Why and what Am I?: The Confessions
of an Inquirer (1857): "I wish to learn to what extent I am I...."