Project:Policies specific to identities

Introduction

In philosophy, the concept of identity is used to name the relation that a thing has in and of itself which it uniquely bears. Even in this greatly simplified form, the concept gives rise to a number of difficult questions, for which we do not have agreed upon answers. For example, x and y share all their properties, are they the same? If x changes its properties does it become a new object or is it still x?

Linguistically, philosophers may differentiate between qualitative and numerical (or quantitative) identity. For instance, we may say that two friends have the "same" phone, but what we mean is that they have different instances of the same kind of phone. This is said to be qualitative identity. Alternatively, if we mention that two siblings have the "same" parent, we are in fact referring to the exact "same" person as having a numerical identity.

Numerical identity is a concept which is easily applied by individuals on a daily basis. It is the foundational element of most legal systems and many religious systems which place emphasis on the individual. For example, if an individual commits a crime, they may be arrested for it. But how do we know that person is the "same" person that committed the crime? If a long enough time has passed and all the cells in their body have died and been replaced, are they really the "same"? If they've changed their name are they really the "same"? If they've changed their appearance via cosmetics or surgery are they really the "same"? Even the very concept of imprisonment is supposed to be "reforming" the individual, i.e. causing them to be "different" than when they were first incarcerated.