When you switch on a lightbulb, your eyes perceive photons, and some neurons in your brain activate. If you switch off the light, then so-called ‘off’ neurons activate.
Photoreceptors include rods, which are responsible for the detection of dim light, and cones, which function in bright light and are responsible for the ability to distinguish colours based on their unique spectral sensitivities. These cells each have a ciliary process, known as an outer segment, that consists of stacks of membranous discs where the proteins involved in light sensing and signalling are located. The rods and cones connect to bipolar cells. There are also neurons responsible for modifying visual signals, such as amacrine cells, which connect rod bipolar cells to cone bipolar cells, and horizontal cells, which mediate feedback inhibition to the photoreceptors. The cone bipolar cells connect to ganglion cells, which integrate the signals from the upstream neurons. The ganglion cell axons assemble to form the optic nerve for transmission of visual signals to the brain.[1]
You don’t actually “stop seeing” when you’re in the dark. No; the mind physically represents nothingness in a pattern of neurons. In the case of literal darkness (as opposed to cognitive dimness), photoreceptors include a special adaptation that allows us to see, even when there appears to be very little light.
Similarly, in physics, there is darkness—the void of space. But is it entirely correct to claim that it is empty? Scientists posit that it is populated with vacuum energy. Vacuum energy is a theoretical background energy throughout the universe, as modeled by the uncertainty principle.
The uncertainty principle can be visualized in this way: imagine a field where virtual particles are constantly popping in and out of existence, imperceptible to the eyes but verifiable by deduction and lab experiments. The implication of this is that the universe is, in a sense, 'charged.' This is a tenet of quantum field theory.
This theory additionally predicts a significant amount of hypothetical energy throughout the universe. But it seems to bear little cosmological consequence, as the energy density that we actually observe is much smaller than the hypothesized model.
But if we assume the standard model is correct, this knowledge gap is known as the cosmological constant problem. It is one of several ideas put forth to account for hidden (dark) states of matter and energy implied by the universe's accelerating expansion. The thing I'm pointing at here is that there's a gap--something is there, and even if it isn't "dark energy" -- then it is, at the very least, a gap in our understanding of the universe.
The point I’m trying to draw, however, is that when we attempt to observe or discuss "nothing," we inevitably encounter "something"—or we find that "nothing" itself is a direct or indirect reference to "something." I argue that it’s impossible to truly discuss "nothing." In a genuine vacuum, a place where absolutely nothing exists, there wouldn't be any fields to measure. There would be no spacetime to speculate about.
In that vein, asking "Why is there something rather than nothing?" is a category error. If we were to ask, "Why is it snowing?" one could at least try to formulate an answer: "Due to cold temperatures, water in the atmosphere froze and fell to the ground as ice crystals." In this scenario, we are asking about a specific feature of the map. Alternatively, we could claim it was because a giant snowman god in the sky caused it to snow. On the other hand, the question "Why is there something rather than nothing?" is unknowable, because we are no longer asking about a specific abstraction of the map—instead, you're asking what created the map itself.
Similarly, the phrase “nothing exists” is a kind of inverse category error—a claim that nothing is real. However, labels like "absence" or "nothing" often function as references or pointers to other things.
If we must say it, the phrase "nothing exists" is not a self-contradicting statement but a humorous or horrifying statement of fact. Nothing exists.
"Nothing could ruin this moment." "Nothing can dim this light." "Nothing is too great a challenge." "Nothing lasts forever."