Self-awareness early philosophical discussion of self-awareness is that of John Locke. Locke was apparently influenced by René Descartes' statement normally translated 'I think, therefore I am' ("Cogito ergo sum"). In chapter XXVII "On Identity and Diversity" of Locke's "An Essay Concerning Human Understanding" (1689) he conceptualized consciousness as the repeated self-identification of oneself through which moral responsibility could be attributed to the subject—and therefore punishment and guiltiness justified, as critics such as Nietzsche would point out, affirming "...the psychology of conscience is not 'the voice of God in man'; it is the instinct of cruelty ... expressed, for the first time,
Cogito, ergo sum and that "I" know what "thinking" is. He suggested a more appropriate phrase would be "it thinks" wherein the "it" could be an impersonal subject as in the sentence "It is raining." The Danish philosopher Søren Kierkegaard calls the phrase a tautology in his "Concluding Unscientific Postscript". He argues that the "cogito" already presupposes the existence of "I", and therefore concluding with existence is logically trivial. Kierkegaard's argument can be made clearer if one extracts the premise "I think" into the premises "'x' thinks" and "I am that 'x'", where "x" is used as a placeholder in order to disambiguate