A boy grows up in rural South Africa, raised partly by his white family and partly by the local black people. He is particularly impressed by the tribal shaman. As he grows up and travels, he has many life experiences that are characterized by indecision about moral and ethical issues, particularly race-related issues. When he returns to South Africa, the shaman is still there and still wise. The shaman offers the young man a chance to fulfill himself; they take a drug and their spirit selves become enlarged, so large that they are of astronomical size, looking down on the tiny Earth. The shaman, who has no doubt in him whatever, turns to his protege and says that is now time to act. When the young man, again, fails to make a forthright decision, the shaman turns back to the Earth and spits on it. The Earth crackles briefly and is gone, obliterated, whereupon the spirit shaman enlarges rapidly to become one with the universe. But the young man's spirit is left to drift through space, his scream engulfing the stars.
The story was one of the first that I read in a new science fiction magazine, fresh off a news stand, in English, probably in the late 1960s. I would not be surprised if I have some of the details out of place, but the end of the story is distinctive.