does nothing really come of nothing?
cordelia tells lear that she has notihng to tell him, because she doesn't have anything more to offer than the love of a daughter for a father. nothing seems to really come for nothing in the end of the play, with the good and evil characters both dying. Lear, and CoRdelia, both die in the end, proving this fact.
i think it is interesting that once lear finally comes to realize cordelias love for him, it is too late, and he and her both end up dying. it shows that human nature is to doubt, and perhaps be selfish.