Before I proceed to enlighten you through a few well-chosen paragraphs, side-stepping all those ridiculous disciplines, such as meditation, that usually are regarded as necessary to achieve this elevated understanding, my inner attorney demands that I add some metaphorical fine print to the title of this blog post:
First, you should indeed soon be enlightened as to the ultimate nature of the cosmos. However, don't expect that this will be, well, what you expect.
Second, my guarantee is related to my just-mentioned "first." Have no doubt that my words will take you to the furthest reaches of reality. But if you anticipate what this experience will be like, I can't guarantee that my guarantee will match yours.
That said, let's get on with the saying.
Sagan points out that if we ask how the cosmos came to be, and someone claims God created it, the next question is "And what created God?" If the answer is that God has always existed, then why not save a step and simply say, "The cosmos always has existed"?
Which brings me to my promised enlightenment.
All you need to do is this: ponder the fact that existence always has existed. That is, something always has existed.
Even if you're scientifically minded and envision universe particles popping out of a cosmic quantum vacuum, "quantum" and "vacuum" are something, not nothing.
Don't be half-assed with your pondering.
Stick with it until you reach a brain freeze, an existential brick wall, the place where your train of thought crashes into an abyss of What the Fuck?! and you find yourself in the engineer's seat staring straight at an unfathomable black hole of pitch black mystery.
Get to that place.
Feel what it's like. Doesn't matter for how long. A milli-second will do. That sensation of Ahhhhhh... Ohhhhhhh... Ooooooohh... or whatever -- that's enlightenment.
Because you've grasped what the endpoint of knowledge, of experience, of living, of dying, of reality, is. It doesn't matter that you haven't traversed all of the territory in between here and there.
You've gotten an intuitive feel for Existence exists. Amazing! If that feeling came to be continous, you'd be continuously enlightened.
In some traditions, "enlightenment" is said to be the recognition that there's no such thing as enlightenment. That fits well with how I see the situation.
Enlightenment is like Wile E. Coyote running into a rock wall while chasing the Road Runner, something he did a lot of in the cartoons that I avidly watched in my childhood.
He'd get flat as a pancake. Then slowly peel himself off the wall and pop back into his three-dimensional self.
Existence is that wall. Enlightenment is that pancaking. It's the realization that, in the end, there's nothing to realize.
Existence is. Just as we are. Existence always is.
Whether we are also... that depends on how we view "we." The atoms and energy which comprise "me" likely always will exist in some sense, since there is no place for existence to depart to (given that any possible destination would exist).
Early on every human is conditioned to see causes and effects operating everywhere. Positing "God" is a way for us to feel that we've figured out the ultimate cause. Yet as Sagan says, this is an illusory explanation. On the other side of "God" is stark existence, causeless and effectless.
If this sort of pondering leaves a chill in your spine, bodily or philosophically, this is a sign of your enlightenment.
This can't be experienced, understood, or known. All we can do is know in a knowledge that is beyond knowing, This can't be experienced or understood.