What constitutes a duty? I read somewhere that the elderly who are very ill have a “duty to die” in order to relieve taxpayers of taxes to pay for the elderly’s healthcare. Is this assessment fair? Do the elderly have a duty to kill themselves if they are already being a burden to others and society in general?

Leaving aside the gargantuan question 'what constitutes a duty?', let's focus on the question of whether the elderly ever have a duty to die.

In a famous article http://web.utk.edu/~jhardwig/dutydie.htm, John Hardwig argues that some elderly or ill individuals have a duty to die. Very roughly, his thought is that one can have an obligation not to impose unfair burdens on others (financial, emotional, etc.). Since the ill or elderly often have medical conditions that are unduly burdensome to others, then if the only route to their avoiding imposing these burdens is for them to end their lives prematurely, then they have (according to Hardwig) a duty to die.

Hardwig's argument evoked a great deal of hostility when it was first published, and few philosophers have accepted it without controversy. Some of these criticisms are collected here http://www.amazon.com/There-Duty-Die-Bioethics-Reflective/dp/0415922429/... and http://www.amazon.com/There-Duty-Biomedical-Ethics-Reviews/dp/1617371874...

My own take on Hardwig's argument http://onlinelibrary.wiley.com/doi/10.1111/j.1467-8519.2008.00723.x/abst... is that while there may in principle be a duty to die, it's a lot rarer than Hardwig supposes. I propose that if a person has a duty to die, then others would have a right to kill her in self-defense; but because others generally do not have such a right under the conditions Hardwig outlines, there is a duty to die only under rare circumstances, and in particular, the elderly and those with long-term illnesses do not have such a duty.

Read another response by Michael Cholbi
Read another response about Ethics, Death