Christopher Hitchens writes in the January edition of Vanity Fair about what he believes to be a nonsensical maxim: "What doesn't kill me, makes me stronger." Hitchens is suffering from esophageal cancer, the primary reason for the sentiment that he is not becoming "stronger," but is rather on a terminal decline.
The phrase is attributed to Nietzsche, whose mental decline late in life, Hitchens notes, probably did not make him any stronger. Nor did the philosopher Sydney Hook consider himself stronger after a terrible experience in a hospital. Hitchens considers himself to be among the many who don't conquer illness to come out stronger. But there is a flaw in this reasoning - the first condition to becoming stronger is to not be killed. Hitchens is thankfully still alive and kicking (i.e. writing), but he hasn't defeated his cancer (yet, hopefully); it is only after the cancer is over with that Hitchens can say he's stronger or weaker. Now is premature. The more important qualification is that "stronger" should mean mentally stronger, not physically. Diseases that target the mind specifically, like Nietzsche's syphilis, should be discounted; all others should hopefully be an exercise for the power of will and mental fortitude.
Whenever you think life is hard, remember Hitchens and countless others who brave horrible diseases. Stay stark, Hitch!
Hitchens's essay may be found here.