Dummett wrote something very sensible about rigid designation in Appendix 3 of The Interpretation of Frege's Philosophy , but apparently the length of the appendix put people off. Dummett is more right than Kripke. I have not seen a deep objection to the thesis that material object statements are translatable into sense-appearance statements. I think that this thesis is true. Online You may need an NUS line for access The Doug Lenat controversy Water is wet.
Birds have two eyes.
Dead people stay dead. For years, Doug Lenat has been teaching a computer millions of these common facts. Lingua Franca September 2001. Chuang Tzu c.300 B.C. The great Taoist philosopher who dreamt that he was a butterfly and then asked if he might not be a butterfly dreaming he was a man. There was a beginning.