He wasn't at all sure of how much he could extrapolate from what he'd read in the book on Applied Semantics, but he knew he needed a control--a symbol of the symbol, in this case.
He did not know how to apply what he read.
mnli hypothesis: He did not know how to apply what he read. premise: He wasn't at all sure of how much he could extrapolate from what he'd read in the book on Applied Semantics, but he knew he needed a control--a symbol of the symbol, in this case.