Hobart explained, "The fourth dimension definitely isn't length, width, and height. It's an additional dimension beyond them. In that dimension, we would be like paper people in three-dimensional space.
"Thinking of how we could pass through enclosed spaces in the Spirit World, the fourth dimension must allow one to easily step beyond the other three dimensions.
"It's like drawing a circle on paper. If there were two-dimensional creatures, the circle would be an insurmountable barrier to the creatures inside it.
"But if one possessed a third dimension, one would only need to walk normally to step out of the circle on the ground."
Alger marveled, "This is a very logical new discovery. Its theory seems quite mature already."
Hobart smiled and shook his head. "In any case, we need to go around such two-dimensional spaces. You saw it just now—once you enter one and come back out, you no longer have any thickness. We become paper people."
It reminded him of a classic science fiction novel he had read in the Common Era.
Alger nodded, but then another question occurred to him. "Why didn't we feel any harm caused by dimensions when we returned from the Spirit World to the real world?"
Hobart smiled. "That's because we returned from a higher dimension to a lower one. Higher dimensions can contain lower dimensions, just as there are planes in the real world. So when we enter a higher dimension, we low-dimensional beings won't be harmed by it.
"But when higher-dimensional creatures enter a lower dimension—for example, if the two of us entered the two-dimensional space ahead—we would lose our thickness. I don't know whether there's any way to recover it. At any rate, I haven't thought of one."
The two discussed the matter as they skirted around the two-dimensional space before