Investigators said the two men, who were described as in their 20s, were arguing about Kant's philosophical ideas while waiting in line to buy beer Sunday at a store in Rostov-on-Don when the argument turned into a fistfight, TV-Novosti reported Tuesday.
The fight ended when one of the men drew a gun and shot the other, wounding him in the head.
Police said the shooter fled the scene and was later arrested with the weapon. He was charged with intentional infliction of serious bodily harm.
The victim was hospitalized with non-life-threatening injuries.