By translating a natural sentence into a crisp, solid logical form, we disambiguate its meaning. Furthermore, if we have logical formulas, then we can apply rules of logic such as modus ponens to make inferences. For example, if all computer courses are challenging, and CSC 173 is a computer course, then it follows logically that CSC 173 is challenging.
This turns out to be one way to tackle NLU. But, maybe you've already noticed, the translation part is not easy. After all, if one can disambiguate the meaning of every sentence flawlessly, what's so hard about NLU? The intrinsic randomness and whims of human languages render the translation 'plausible' at best. Recently, researchers are drawn to the idea that we can treat natural languages themselves as logical forms. This is pioneered by Montague, and this approach is known as Montague grammar. Still, most believe we need some adequate way to represent knowledge. Lenhart Schubert's episodic logic is one example of such representations.