<prompt> Translate the following text to EnglishHakuwa na uhakika kabisa ni kiasi gani angeweza kuhitimisha kutoka kwa kile alichokuwa amesoma katika kitabu cha Applied Semantics, lakini alijua alihitaji udhibiti - ishara ya ishara, katika kesi hii.  <response>: He wasnt at all sure of how much he could extrapolate from what hed read in the book on Applied Semantics, but he knew he needed a control--a symbol of the symbol, in this case. 