In Europe it was the custom to fatten up geese in the months preceding Passover, since many families refrained from using any oil other than goose fat. For six to eight weeks the geese would be fed a full bucket of corn twice a day, so that by the time the holiday arrived they would be so huge they could barely waddle.
Two religious giants of the day, the Chasam Sofer (Rabbi Moshe Sofer) and the Yismach Moshe (Rabbi Moshe Teitelbaum) differed in their rulings as to whether the practice of force-feeding rendered the geese treife. The question revolved around whether or not the sharp corn grains which were forced down the throats of the birds would damage the esophagus, thus making the birds treife (i.e., unable to live another year). The Chasam Sofer held that the esophagus would not necessarily be damaged, and so he ruled the practice permissible. (Of course, the geese had to be carefully checked before being consumed to prove that they were kosher by the process described later.) His contemporary, the Yismach Moshe felt that since the corn kernels were sharp, the likelihood was that the birds would be rendered treife by the force feedings. He ruled that geese fed in this manner would not be permissible.
The two corresponded back and forth, each presenting learned arguments to prove his point, their dispute purely "for the sake of heaven." Finally, the Chasam Sofer suggested that instead of theorizing, they should put their rulings to a practical test. Each was to take ten geese and fattened them up. Then, they would slaughter them, fill the esophagi with air and float them in a full tub of water. If the esophagus was damaged air bubbles would escape into the water, thus proving that the bird was treife. If no bubbles were seen, the bird would be kosher.
When the birds were duly fattened and slaughtered, an amazing thing took place. All the birds from the household of the Chasam Sofer proved to be kosher, whereas all the birds of the Yismach Moshe tested treife.
So it was seen that the legal rulings of these two great giants dominated the physical reality, proving the axiom that the rulings of true halachic authorities determine the actual reality of a physical situation.
