": How many senses do worms have? : They have two: smell and touch. Why? : So, they live without any ability to see or even know about light, right? The notion of light to them is unimaginable. : Yeah. : But we humans, we know that light exists—all around them, right on top of them, they cannot sense it. But with a little mutation, they do. Right? : Correct. : So, Doctor Eye, perhaps some humans, rare humans, have mutated to have another sense—a spirit sense—and can perceive a world that is right on top of us, everywhere, just like the light on these worms."