I will agree that when we see someone become sluggish, refuse to eat or exercise, etc., we may infer from this behavior that he or she has "lost the will to live" (although, if they live despite behaving this way, the same things are seen as caused by the illness, and are obstacles that their "will to live" was able to overcome), but as explained above, if we then say that losing one's will to live caused these behaviors, we are defining that will circularly.jmercer said:Perhaps we should discuss what the difference in lifestyle is between someone who has the "will to live" and someone who doesn't.
People have already cited the effect attitude has on eating, drinking, etc. Someone who's lost the will to live becomes sluggish, doesn't eat well or properly, doesn't get enough exercise, fails to take medicine on time, refuses to accept therapy, becomes depressed and anxious, etc., etc. All of these things tend to run a body down, lower resistance to disease, and create stress which also harms the body over time. These things can become critical factors - especially if the injury or treatment already lowers the immune system's ability to protect the body.
I may be reading you wrong, but it seems that here you are indeed seeing this inferred will to live as the causal agent. Again, this is like saying things fall because of gravity; it is a commonly accepted, but technically quite incorrect, assignation of causation.
So in my opinion, a lack of will to live actually harms a person - or drives them to indirectly harm themselves.
What evidence do you have that it was his desire to live that got him out of bed? Aside from the fact that he did get out, that is? Certainly, if we wanted to we could (although it would not be the culturally normal thing to do, it would be every bit as consistent with the evidence) say he got moving because of a will not to be a problem for the family...or a desire to prove the doctors wrong...or the will of one particular god or another...or Sylvia's kind thoughts...
Alternatively, my father's desire to live got him out of bed after the liver operation amazingly fast, and drove him to become physically active quite quickly. He kept an optimistic attitude, ate well, and actually took better care of himself than he did before his diagnosis. These things all served to help maintain his immune system and kept his body healthy other than the cancer.
So here, you are clear in claiming causality. But it is clearly circular. He was able to sustain his activities longer than expected, and from this we infer an increased will to live. Then, we say that this will to live, for which we have only the evidence of the sustained activity, was in fact the cause of the sustained activity. Logically, it is every bit as much evidence of Sylvia's help. That is, it is not evidence at all.
All of these factors certainly contributed to his survival - especially with periodic chemo and radiation therapy being the norm. His ability to sustain those activities for as long as he did was - in my opinion - directly due to his will to survive, which changed his lifestyle dramatically.
What of the people who engage in these activities and die anyway? Would you say they died despite a huge will to live? Perhaps you would--it seems consistent with your examples here. If that is the case, I suggest that you are using the term very differently than it is commonly used. (I saw an article in The Onion, headlined "local man loses cowardly battle with illness" or something similar. It points out that there are some phrases we only use half of--we say someone fought bravely against cancer, but never say someone was a coward in that situation. We say someone's will to survive pulled them through, but we never say they died in spite of never having given up. Surely, if it was a real and measurable thing, it would have failed once or twice...but no, we read instead "after months of painful struggle, during which he never lost the will to survive, Mr. Z finally, late one February morning, quietly gave up the fight." The only evidence that he "gave up the fight" is that he died, but it is unacceptable to us that you can die despite fighting with all your will...so of course...he gave up the fight, and it was his choice to die.)
There may or may not be any more to it than this. I don't know. But I think that these items are significant enough that people with the "will to live" increase their chance of survival through sustaining these activities and actions.