Existence exists is an axiom which states that there is something,
as opposed to nothing.
At the core of every thought is the observation that "I am aware of something".
The very fact that one is aware of something is the proof that something in some form exists -- that existence exists
-- existence being all that which exists.
Also, to grasp the thought, "I am aware of something," you must be conscious.
Existence is axiomatic because it is necessary for all knowledge
and it cannot be denied without conceding its truth.
To deny existence is to say that something doesn't exist. A denial of something is only possible if existence exists.
To exist, an existent (an entity that exists) must have a particular identity.
A thing cannot exist without existing as something,
otherwise it would be nothing and it would not exist.
In the statement "something exists", the something refers to the axiom of identity
and the exists refers to the axiom of existence.
They cannot be separated and are like two sides of the same coin
or two ways of understanding the same axiom.
(This page mirrored from Importance of Philosophy.com)