Human life is so precious, it seems crass to put a price on it. How can a pile of coins, paper or gold bars match a year on Earth? Life should be, quite literally, invaluable.

Yet that is the morbid question that health services, everywhere, inevitably have to ask. They have limited money to spend on sick and dying people, and whenever a new drug becomes available, they have to make a choice: will the few stolen months, or years, be worth the money it costs?

Our gut instincts may seem obvious: we should do all that we can to buy more time for the people we love. Yet Dominic Wilkinson, an intensive care doctor and ethicist at the University of Oxford’s Uehiro Centre for Practical Ethics recently wrote a thought-provoking article questioning these assumptions and asks us all to consider just how much we should be willing to pay for a longer life.

Intrigued, BBC Future phoned him to explore his argument, and to better understand the ways we currently calculate the price of life.