In line with the empiricist project, Locke tries to describe how unconscious encounters with environment yield to the emergence of consciousness. For Locke the self is identical with consciousness and consciousness is accessible empirically. As far as the identity of human is concerned, identity of the self depends on the consciousness of the person. The person is identical to himself to the extent that he is aware of his own perceptions and thinking. The range of the person’s memory sets the limits of consciousness. According to Locke, consciousness is an element that accompanies all acts of thinking including act of recollection. Such accompanying consciousness constitutes the form of the identity of the self, whereas memory-ideas may be considered the content of consciousness. Therefore, it is this formal constitutive element that provides constancy of the idea of the self. If so, then it can be claimed that Locke’s approach to the question of the self results in admitting the truth of what he intends to reject and it is self-defeating; this is to say that, Locke’s methodology pushes him to adopt a Platonic-Aristotelian formal theory of identity in general and of personal identity in particular.