Take notice of the language authors will sometimes use when they are speculating about things or hoping you won’t realize that the evidence is weak: “it is probable or likely that,” (is it probable?) “clearly, this is so” (is it clear?), “it should be obvious by now” (is it obvious?), “this undoubtably means” (is it undoubtable?) Remember that forceful words don’t necessarily make a weak argument any more convincing.