Original sentence: Heuristics, in this sense, is treated as a singular, like physics or mathematics.The study of heuristics is sometimes called heuristic, but more often called heuristics
Edited sentence: Lexical note: The name of the topic is heuristic (not "heuristics"); a particular technique of directing your attention toward discovery is a heuristic, two or more of these are heuristics, and the adjective for "pertaining to how something is discovered" is heuristic