"Law of Identity"
Centuries ago, Aristotle one of the greatest of philosophers, has stated the formula defining the concept of existence and the rule of all knowledge: A is A. A thing is itself.
Existence is Identity, Consciousness is Identification.
To exist is to be something, as distinguished from the nothing of non-existence, it is to be an entity of a specific nature made of specific attributes.
Whatever you choose to consider, be it an object, an attribute or an action, the law of identity remains the same. A leaf cannot be a stone at the same time, it cannot be all red and all green at the same time, it cannot freeze and burn at the same time. A tree cannot be a telephone, and a dog cannot be a cat. Each entity exists as something specific, its identity is particular, and it cannot exist as something else. An entity can have more than one characteristic, but any characteristic it has is a part of its identity. A car can be both blue and red, but not at the same time or not in the same respect. Whatever portion is blue cannot be red at the same time, in the same way. Half the car can be red, and the other half blue. But the whole car can't be both red and blue. These two traits, blue and red, each have single, particular identities. The concept of identity is important because it makes explicit that reality has a definite nature. Since reality has an identity, it is knowable. A is A.
Honesty is the rejection of unreality. It is the recognition that pretending (to oneself or to others) that the facts are other than they are does not change the facts, and that therefore the dishonest man is allying himself with non-existence: he is making reality his enemy. He proclaims that there is no law of identity, that nothing exists but change, and blank out the fact that change presupposes the concepts of what changes, from what and to what, that without the law of identity no such concept as "change" is possible.
Are you seeking to know what is wrong with the world? All the disasters that have wrecked your world, came from your leaders' attempt to evade the fact that A is A. All the secret evil you dread to face within you and all the pain you have ever endured, came from your own attempt to evade the fact that A is A. The purpose of those who taught you to evade it, was to make you forget that Man is Man.
No matter how eagerly you claim that the goal of your mystic wishing is a higher mode of life, the rebellion against identity is the wish for non-existence. The desire not to be anything is the desire not to be.
