Lem

I believe I asked this befoere and it was answered but it's hard to lacoate in the archives:  WHat is the name of the story by Stanislaw Lem in which characters ponder the possibility that mathematical parameters could be written for a field such that mathematical entities inhabiting that field would take it fdor having properties of time and space, even though it is actually dimensionless?  (Kicker being of course that yes they can and the inhabitants are us.)  Help?