The Empty Cup Is the Fullest

Imagine a glass. It was designed to hold water. We can judge its state by observing the amount of water it holds. Basically, its state can be divided into two kinds:

• Empty cup: the state in which not a single drop of liquid exists in the glass;
• Water cup: the state in which liquid exists in the glass.

We want to ask: between the empty-cup state and the water-cup state, which is more “full”? Of course, we need to define the state of being “full.” Roughly speaking, every cup has its capacity, and we can say that the full state is the state in which the volume of liquid in the cup equals the cup’s capacity¹. Then the judgment of which is “fuller” can be made by judging its “distance” from the “full” state: the state in which the volume of liquid in the cup is closer to the cup’s capacity is called the “fuller” state.

Therefore, under this definition, the water-cup state is fuller than the empty-cup state.

Since cups were “made to hold water,” if cups had their own little world and took this idea as the social consensus of their society, empty cups would surely feel quite hollow—envying, without realizing it, those cups that held water; looking at them and feeling an emptiness inside: after all, cups were “made to hold water”!

So, in such a little world, suppose there existed a waterfall (say, a faucet turned on beside the sink). No cup could resist its temptation, because nothing could satisfy a cup’s—especially an empty cup’s—need for self-realization better than this spring gushing down from the sky: after all, cups were “made to hold water”!

Let us pull the camera away from the world of cups. As the owner of the cups, the grand turbulence of the cup world has nothing to do with me. To me, I have merely turned on a faucet casually, and I can turn it off at any time. And when I casually pour out the water in a cup, perhaps for that cup it is a de-capacitating disaster (cups have no heads to lose, after all). What remains for that cup is endless emptiness².

The greatest difference between people and cups is that people know more of the laws of the physical world. People know that holding water is holding, holding rice is holding, and holding pebbles is also holding. In fact, so-called “holding” is merely a relation of containment, and “full” is merely the special state in which that containment relation reaches a critical point. And defining “full” as “filled with water” arises solely from the common idea that cups were “made to hold water.”

Therefore, at least as human beings, we can very easily set aside the established idea that “filled with water” = “full” and examine what, for a cup, “full” actually is. Once separated from the perspective of “holding water,” so-called “full” in fact becomes the state of filling a cup’s capacity with some medium.

Common sense in life tells us that, under this definition, so-called “filling up” is not an absolutely stable point: the liquid surface may approach the rim, and it may also briefly rise above the rim because of surface tension; but it always depends on concrete conditions, and it is easily rewritten by tiny disturbances in the environment.

I imagine the cup world knows this too, and so they may also conduct research to explore to what degree a cup can hold more water—they may even invent contact angle, wetting, surface tension, and even thermodynamics, even an entire system of physics! How impressive.

Perhaps one day, cup physicists will discover that by properly regulating surface tension and the wettability of the cup wall, the water surface can indeed rise above the rim. The cups might call this state “overfull.” Yet this overfullness is not secure; a slight vibration, a speck of dust, or the bursting of a bubble may all cause the raised layer of water to slide down along the cup wall. Thus a moment of ecstasy becomes a moment of loss; and after such losses have been experienced many times, perhaps they gradually become numbness.

But in fact, there exists a way outside the kaleidoscopic emotions of ecstasy, loss, numbness, and the like: without struggling over how surface tension obstructs the goal of “approaching being full of water infinitely closely,” one can directly realize the goal of being “full.”

This is the state of the empty cup. The empty cup holds no water, yet because it is always in air, it is always full of air—it has done nothing, yet it has already leapt across the cup world’s hard-won, torch-passed ten million cup-years and achieved the final goal all cups have awaited together.

Better still, seen from this perspective, whether a cup has water in it is not actually important to the state of whether the cup is “full”—as long as cups are in air, they will inevitably divide their own capacity into two parts, air and water: water fills the obvious volume, while air silently lets the state of “fullness” be accomplished at the very moment the cup is made.

The names water and air are not important. Whatever world a cup is born into, that world enters the cup in its own way; what the cup calls empty is merely a fullness it has not yet learned to name—this “fullness” need not always come from something poured in from outside; sometimes, it comes from the cup finally realizing that its interior has never been barren.

In truth, it is not that they have not yet learned.

It is only that the cups have forgotten.

It is only that people have forgotten.

The cups can remember at any time, because the air that keeps them company day after day hides the answer.

People can remember at any time, because what keeps them company day after day is the answer.

1. ¹There are of course some measurement errors here, but allow me to ignore them.
2. ²If such a situation really exists, I am not sorry, cups.