Eh, in this case I don't think the story hinges on keeping that secret, and if you know what era of sci-fi the story was written in you'd be nearly certain you're getting the "shocking twist! (but not really a twist)" ending anyway. The alert, seasoned sci-fi reader would be more surprised by almost any other ending than that one, really, in a '50s story of this sort.
Same thing Asimov usually did—a shower and/or stoned "what if...?" idea turned into a short story in a straightforward way—except Clarke took the extra step to, like, write actual characters and draw a setting and maybe even establish tone and mood beyond whatever the literal plot itself necessarily conveys.
I'm fairly certain this is from Arthur C. Clarke's short story "The Nine Billion Names of God", partly used as inspiration for 2001: A Space Odyssey.