My daughter, Susie, is a scant five feet tall. She went to the University of North Carolina at the same time as six-foot-six-inch Michael Jordan. One day, they both got in an empty dorm elevator together. The door closed; one looked up, one looked down and they both spontaneously started laughing. 

Scale is important.

And no matter how many times you’ve seen Monet’s waterlilies in books, on computer screens or in slide shows, you are not prepared for the wallop they have in person at the Orangerie. They spread out across your vision from one peripheral side to the other.

Scale matters.

In 1972, Apollo 17 astronauts photographed the “Blue Marble” Earth from roughly 18,000 miles, giving us an image of the wet, watery ball we live on. It looks small and vulnerable — and it is, in the immensity of space. But it also gives a misleading impression of the scale of the planet.

Scientists may measure scale with numbers and exponents, but each of us, personally, can only conceptualize size and distance against our bodies and senses. Who of us can tell the immediate difference between 10¹¹ and 11¹⁰? Which is the larger number? But between your fingers, you can tell which of two grains of sand is larger, merely by feel. 

In 2008, I drove from Phoenix, Ariz. to Reidsville, N.C., over a weekend, a trip of about 2,200 miles, or roughly 1/11th of the circumference of the globe. I left after work on a Friday and pulled in to Reidsville on Monday morning. I was hauling ass, as they say. On the Sunday, I drove 900 miles. The trip was exhausting, but gave me a palpable sense of the size of the world. I could feel it, because I drove over it.

(And, by the way, the world is not flat: I could see the great grain elevators of the Midwest rise from the curved horizon before me and, after I passed, watch them settle, like the setting sun, behind me.)

In 1989, I flew from Phoenix to South Africa, a flight that spent some 40 hours in the air. The popular image is that if you dig straight down in your back yard in America, you eventually hit China, but this isn’t so. Directly opposite Phoenix on the Great Blue Marble is a spot in the Indian Ocean just off the coast of South Africa. 

So my flight was literally to the antipodes. (It took so long because in that apartheid era, I had to take an especially roundabout route to my destination: Phoenix to Philadelphia, changing flights to Frankfurt, Germany, changing again to a South Africa Airlines flight that, because of opposition to apartheid, was not permitted to overfly most other nations in Africa, and so, had to fly out over the Atlantic, refuel in the Azores, and cruise over the water all the way to Namibia before finally landing in Johannesburg.) It took Lindbergh 33 hours to cross just the Atlantic.

Such a trip really gives you a sense of the scale of the planet.

Before air travel, however, such a voyage would take months, not hours, providing an even more body-interior feel for the distance. In 1967, I took a trans-Atlantic ocean liner to Europe, and the monotony of the unchanging sea, day to day, made the earth seem even larger. My trip took four days and a bit. It took Columbus more than two months to cross the Atlantic.

The point I am making with all this travel tale, is that scale, whether looking at Picasso’s Guernica, or watching the odometer while driving from Bangor to Seattle, is that scale is felt in the body, it is measured by human proportions. As Protagoras recognized in the Fifth Century BC, “Man is the measure of all things.”

When we look out at the night sky and realize we are at the bottom of a seemingly infinite and dark well, we can be awed, but we cannot feel in our bodies the inestimable size of the cosmos.

Yes, we can speak of it in abstractions. We can point out that Voyager I, now in interstellar space, is traveling at a speed of 17,000 miles per second — which would take about a second and a half to circle the Earth — and will cover 325 million miles in a year. Yet, at that speed, it would take it  some 45 thousand years to reach the nearest star. There is no way you can process that scale in your paltry human skin. We can talk in big words, like billions and trillions, but outside of abstract mathematical numbers, can you actually feel the difference between a billion miles and a trillion? They are meaningless words. You might as accurately call it a “gazillion.”

Do not misunderstand me. Humans have been amazing at understanding the cosmos intellectually. We can calculate the orbit of a satellite within what seems like a few inches. But I am not talking here about abstract reasoning.

There is a limit to the human imagination. We can calculate overwhelming numbers, but in terms of body knowledge — being able to physically conceptualize — such numbers turn into little more than words. 

We can use the math for engineering and for science, but we must recognize that our puny minds cannot get their arms around such boggling numbers. We are limited by the evolution of our human brains, which grew to process the daily income of sense data. We can feel the road under us as we speed along the interstate; we cannot feel the gap between Earth and Alpha Centauri. We can name it, but we cannot feel it. 

All trans-human scales are metamorphosed into a single size: Infinite, or might-as-well-be. It is what we feel when we turn our eyes up toward Orion or the Milky Way.

An earlier version of this essay appeared on the Spirit of the Senses website Oct. 2, 2018