Law of Identity:The philosophical premise that every entity has a specific nature, existing in a particular way.
The Law of Identity names a basic fact of reality. It says that things have a specific nature. Because they exist, they exist in a particular form. We are then able to learn about the nature of the entities.
Since things exist in a particular way, it also precludes the possibility of contradictions. Something cannot be both true and false at the same time and in the same respect. Since everything has a nature, it is what it is and isn't anything else.
This lack of contradictions is the basis of logic, which is a method of identifying when our ideas contradict or not. Logic is useful because it identifies areas where are ideas must be false, since reality itself does not contradict itself.