Recon... Miss this point... Essence is like the laws we apply to reality... We impose them and expect reality to conform to them... We generate essence... Essence is a certain meaning we find in reality, but if we did not exist, there would be no essence...

Yes, but as existent beings, the idea of our non-existence is one more essence. We only think in essences. And thoughts of our non-being must always be abstractions. As thought of a reality apart from us is merely an abstraction of ours within "reality" which is also an essence. The "self/reality" dichotomy is a confusion.

And you miss my point again, that essence is meaning and without people there is no meaning...

Now I would say, essence is the incorporation of elements of the past into the moment of the present.
Being is the sequential incorporation of elements of the past into each new moment of experience. Ultimately "existence" (in the sense of material objects) is only temoral not permanent. or some such notion.

The defining tenant of existentialism is the belief that existence, the being of a person, precedes the essence or nature of a person. In other words, there is no human nature. This sounds like the blank slate interpretation of human nature.

Is this proposition really true; can it be verified; or is this just another attempt to escape the firm clutches of determinism?

As I interpret it existence does precede essence in that the physical body must exist before it can posses any essence.

I see what you mean. The tricky part is this. What is existence prior to essence? This is essentially thoughtless existence. The other tricky part is that "physical body" is an abstraction, an essence.

It seems to me that we must devoid of thought in order to be devoid of essence, and only newborns, if even them, are capable of this?

But the existentialist were aiming at something else. That men can redefine themselves indefinitely. They are all branches from the Hegel tree.

here is the structure.

God then Consciousness/Awareness then Higher Mind then Ego then Body.

The Ego is absorbed into the Higher Mind at the death of the Body and transferred to the next Body to traverse his or her next life.

Real essence and Real existence is the same thing. Neither precedes the other.

In philosophy, essence is the attribute or set of attributes that make an object or substance what it fundamentally is, and which it has by necessity, and without which it loses its identity. Essence is contrasted with accident: a property that the object or substance has contingently, without which the substance can still retain its identity.

To add some backgrounding....

If you had never heard of God and a higher mind from someone you would see the absurdity in that statement!

God and a higher mind are creations of your actual mind and is a way of denying this world and this life is all we get.

If any one person had never heard of God, it wouldn't make God any less real to those who believe in what they refer to as God. It could be argued that anything wouldn't exist without a mind conceiving it, but does that mean that nothing is real?

It reminds me of St. Anselm's ontological argument for God, as he describes God as simply that-which-nothing-greater-can-be-thought. There must be some being which is one that nothing-greater-can-be-thought, and if that being (not just a being, but being in its totality) is conceivable, then it must exist. If God is existence, that would make existence his essence, so if you concede that existence exists, then you would have to agree with St. Anselm's idea of that which is God. It is only when people try to turn God's essence into some certain kind of existence that irrationalities occur.

I believe this is also the theory behind Descartes famous "I think therefore I am" line. To think, one must exist, and to exist, one must exist to some mind; therefore, nothing can exist without a mind of some sort.

I see

in order for one to think one must need a brain

and the brain is built upon .....nutrients , such as minerals , vitamins , carbs etc , hence then , the mind