Sentence:  The embarrassment of these <WSD>theories</WSD> over the naturalness of death is an illustration of the thesis that death cannot be only a punishment , for some termination seems necessary in a life that is lived within the natural order of time and change . 
Meaning of the word marked with <WSD> tags:  a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena