Before I get to the Kabbalah behind the letter hey, I need to ask you a simple question: What's the world made of?

Your high school textbook says energy and matter—whatever those are. Before they had high school textbooks, philosophers thought the world was made of form and matter. Kabbalists say everything is light and packaging. But if you look in the Book of Genesis, you'll see that everything is made of nothing more than G‑d's speech, as King David (a really great kabbalist) puts in the Psalms, "By the word of G‑d, the heavens were made and with the breath of His mouth, all their host."

But then, speech itself has two components. You need air, pumped up from the lungs. And you need to contour that air with certain vibrations, as contributed by the larynx and the mouth cavity.

That's why King David also says, (in the same Psalms), "All that He desires, G‑d does"—implying that there is another element here besides G‑d's speech, and that is G‑d's desire. The speech would be just plain hot air if there was no desire involved to add some vibrations and resonance to that air.

Now, before you begin thinking that all this is arcane babbletalk, let me explain that no, I don't believe that G‑d is an opera star with gigantic lungs pumping out a universe through his throat. Let's get a little abstract here:

Desire:

Human desire is a prison of wants and deficiencies that move us in directions often beyond our control.

Cosmic Desire is entirely His free choice, nothing more than a simple nuance of the Infinite Light in some direction or other.

Speech:

Human speech is how we produce physical sounds so that we can escape our own little shells and share our consciousness with others.

Cosmic Speech is how the Essence of the Infinite transcends itself to generate "otherness".

Comes out that, while we look at the universe and see energy and matter, the Existifier of all of this only sees desire and otherness.

Now, in the Hebrew alefbet, there are two letters that exemplify these two elements of otherness and desire more than all the others. The letter yud is all about desire and form. The letter hey is all about breath. It's the only letter that has no tone of its own, just a signal to breathe out. That breath is what makes the sound go outside of you, to another person. So the hey is all about creating otherness.

That is why King David also said, "For with yud-hey, G‑d forms worlds." Two worlds: The world to come was formed with the yud, while this world was formed with a hey. This world is like a hey, because it's whole theme is "here I am, here I was, I am just a thing that is." It doesn't speak out about how it's being brought into being at every moment out of total nothingness—you have to figure that out on your own.

The world-to-come theme is "I'm an art form, an expression of the desires of my creator."

Really, the world-to-come is nothing more than the inner reality of this world. Our job is to look beyond the outer façade that conceals it and fuse together desire and otherness, light and the packaging of light, form and matter, energy and its mediums, the yud and the hey.