Inter-Conceptual Travel
A man lives on an island, completely alone, and wishes to test his own strength.
So he lifts a boulder, to move it away from the pond, and notices he can’t.
He builds himself up, lifting smaller boulders, daily, until he becomes stronger.
One day, he goes to the big boulder, and is able to move it.
He is now strong.

Growing up, DragonBall Z had this device that could gauge the strength of a warrior.
A green screen would light up, and it would assign a number to each person.
But the main thing that assigned “strength” was a comparison between other warriors.
Now the man on the island needing to test his strength,
has nobody to compare to right?
In a way, he’s comparing to earlier versions of himself.
Strength is relative, so we actually need other beings to test our strength. Unless of course there is a unit of power… wait there is!
A surfer needs no-one to know his strength. The height of the wave, and its speed, give it power. As he looks back at the monster about to smash into him, and he rides it, he has conquered a massive moving object.
The surfer is strong.
So then the surfer meets a man who looks strong, but the total Wattage he can output is far far lower than any wave he’s faced.
Others test their strength against people. In many ways, the most at risk guys are actually bigger, because they are calling on people to test themselves. It is in a way a global, real-life Elo contest.
Now why God created such a Universe, is beyond any reasoning or imagination.
Perhaps, the external is needed to test the internal. A surfer conquering the wave in essence conquers himself. An earlier version of himself. And he also knows himself. There is no better way to know yourself, than through these tests.
So if we were to test a machine, to know how good it is, you would of course throw all kinds of things at it. Car-safety tests. Mileage. Comfort. Quiet. You would want to know! How good are you? How kind. How responsive under stress. Creative.