If you note all the quotations Korzybski heads his chapters and sections with, you may discover that Korzybski took his theories from the time-binding record of philosophers, scientists, and mathematicians, not to mention others. Hume is just one of the sources of the theoretical foundations of general semantics. The "sceptical" view was first recorded in fragment 34 of Xenophanes. Here the "jump" is all the way from the event to the language in which it is expressed, recognizing that there is a difference between what "is" (the event level) and what is said (verbal levels). The Greeks were well aware of this distinction as is illustrated in Plato's metaphor of the caves. This perspective was "lost" through the middle ages when the "church" dominated thinking with its characteristic intensional orientation.
Locke (1632-1704) distinguished between "ideas", some of which we call "objects", language, and events. Locke held that we only "know" our ideas - of three kinds; "sensitive", which we call "objects"; "demonstrative", which we might call "corroborating evidence"; and "intuitive", which we might call "intensional" (math, logic) - categories which have been refined. Already we can see beginnings of the three stage distinction which we technically refer to as event, object, and label.
Hume, 1711-1776, builds on and refines the developing paradigm, which is already fairly formed as empiricism.
Time-binding is somewhat like drawing a picture. Each new learning adds to the picture. Some lines must be erased or changed. Eventually there comes a time when the artist says, "Enough!" and ceases to update. When can an onlooker "recognize" the picture? Can some do so before others? Is that like saying "this philosopher" (who has the cumulative strokes of the past artist work) "gets it"? Will different readers think different philosophers "got it" at different times (thus revealing the reader in the evaluation)? [The map reflects the map maker.]
I'm inclined to think that they all "got it", "it" being a step in the sequence towards the next paradigm. Each was "forward looking" for their time.
"Locke defines knowledge as the perception of the agreement or disagreement between 'ideas'." (Wiki).
Reading a philosopher and thinking that philosopher "gets it" illustrates "agreement" between the readers own "ideas" and the readers "ideas" abstracted from reading the philosopher.