Personal identity is the unique identity of persons through time. That is to say, the necessary and sufficient conditions under which a person at one time and a person at another time can be said to be the same person, persisting through time. In the modern philosophy of mind, this concept of personal identity is sometimes referred to as the ' problem of personal identity. The ' problem is grounded in the question of what features or traits characterize a given person at one time. Identity is an issue for both continental philosophy and analytic philosophy. A key question in continental philosophy is in what sense we can maintain the modern conception of identity, while realizing many of our prior assumptions about the world are incorrect. Proposed solutions to the problem of personal identity include continuity of the physical body, continuity of an immaterial mind or soul, continuity of consciousness or memory, the bundle theory ofself, continuity of personality after the death of the physical body, and proposals that there are actually no persons or selves who persist over time at all.
Development of the concept
In ancient Rome, the wordpersona or prosopon originally referred to the masks worn by actors on stage. The various masks represented the various "personae" in the stage play. The concept of person was further developed during the Trinitarian and Christological debates of the 4th and 5th centuries in contrast to the word nature. During the theological debates, some philosophical tools were needed so that the debates could be held on common basis to all theological schools. The purpose of the debate was to establish the relation, similarities and differences between the Lógos/Verbum and God. The philosophical concept of person arose, taking the word "prosopon" from the Greek theatre. Therefore, Christus and God were defined as different "persons". This concept was applied later to the Holy Ghost, the angels and to all human beings. Since then, a number of important changes to the word's meaning and use have taken place, and attempts have been made to redefine the word with varying degrees of adoption and influence. According to Noller, at least six approaches can be distinguished: " The ontological definition of the person as “an individual substance of a rational nature”. The self-consciousness-based definition of the person as a being that “can conceive itself as itself”. The moral-philosophical definition of the person as “an end in itself”. In current analytical debate, the focus has shifted to the relationship between bodily organism and person. The theory of animalism states that persons are essentially animals and that mental or psychological attributes play no role in their identity. Constitution theory, on the other hand, attempts to define the person as a natural and at the same time self-conscious being: the bodily organism constitutes the person without being identical to it. Rather, it forms with it a “unity without identity”. for conceiving the natural-rational unity of the person has emerged recently in the concept of the “person life”."