Law of identity

Main thing

The Law of Identity is a fundamental principle in logic and philosophy. It states that every entity is identical to itself. This means that if something exists, it has a specific nature and characteristics that make it what it is. The Law of Identity is symbolized as A=AA=A, indicating that an entity AA is equal to itself.

For example, if we consider an apple, the Law of Identity tells us that the apple is the apple, highlighting its unique characteristics that distinguish it from other objects.

Terms

• Entity - Anything that exists with specific characteristics. Example: A cat, with its unique features, is an entity.

• Logic - The study of reasoning and argument. Example: Logic examines how we deduce that if A=AA=A and A=BA=B, then B=AB=A.

An analogy

Consider a key. It has a unique shape and design that allows it to open a specific lock. Just like the key, every entity in the world has unique characteristics that define it.

A main misconception

Many people think the Law of Identity is too obvious or trivial to be of any importance. However, it is foundational for all logical reasoning and understanding the nature of entities.

The history

1. Ancient Greece: Philosophers begin to explore the ideas of identity and existence.

2. Aristotle (384–322 BC): Aristotle, living in Ancient Greece, formalizes the Law of Identity among other logical principles.

3. Medieval period: The work of Aristotle, including his logical principles, is preserved and studied by Islamic, Jewish, and Christian scholars.

4. Renaissance to Modern philosophy: The Law of Identity continues to be a fundamental concept, influencing various fields beyond philosophy, including mathematics and computer science.

Aristotle, famous for laying the groundwork for much of Western philosophy, emphasized, "To say of what is that it is not, or of what is not that it is, is false," highlighting the importance of the Law of Identity.

Three cases how to use it right now

1. Mathematics: When solving equations, the Law of Identity helps us understand that each side of the equation must be equal.

2. Computer Science: In programming, variables are used to represent data. The Law of Identity ensures that each variable is equal to its assigned value.

3. Daily Decision Making: When making choices, we rely on the Law of Identity to understand the options clearly. For example, recognizing that a counterfeit bill is not the same as a genuine bill.

Interesting facts

• The Law of Identity is considered one of the three classic laws of thought, alongside the laws of noncontradiction and excluded middle.

• It is foundational for the development of formal logic and mathematics.

• Despite its simplicity, the Law of Identity has profound implications in metaphysics and ontology.

• The Law of Identity is applicable not just to physical objects but also to abstract concepts and mathematical entities.

• Philosophers like Heidegger have linked the Law of Identity to deeper existential and ontological questions.