She said, "You humans build elaborate shelters to protect yourselves against the elements; we have developed our bodies to resist the weather. We revel in rain. Sunlight is intoxicating.
"You have added speed to your legs with machines, wings to your arms with machines. Your machines are like crutches. They give you an immense power, but they atrophy the natural endowments of your body. Could you do this?"
She pointed with a bird-like gesture behind Joel. He swung around. His eyes widened.
The bulkhead had disappeared! He was staring straight through the ship as if it had ceased to exist. He could see the awesome black infinity of deep space speckled with countless pinpoint suns.
Then the bulkhead gathered substance. And he was looking at the blank wall again.
He let his breath escape. "How did you do that?"
"You were seeing with my eyes. Your people have invented machines to do that—the X-ray machine, the fluoroscope. They are crutches. They cannot do half so well as the eye alone!"
"But it's impossible!" he burst out.
She shook her head. "No. Consider the facts. Even in the densest solid, there is more space than matter. Every atom is like a miniature solar system. There is an infinity of space in that bulkhead but only a drop of matter no bigger than a grain of sand. Is it not true?"
Joel nodded.