I never thought about my own mortality much until I was diagnosed with cancer last year. There was always time, I thought breezily, always time for everything. I could be careless and fix things later, make amends later, be a full, proper, grown human being who finished her filing and had napkin rings and little tables in hallways with lamps and paperweights on them, later.

Then the doctor's words romped across my future hopes and expectations like a fire devouring bush.

And while my eyebrows are still singed by the experience, I now wonder if it actually made me a better person, a little less of a fool. I miss the thrill of abandon and risk as I live more carefully, deliberately. But in many ways I am glad I was smacked so forcefully, as even though I am no longer panicked, I am conscious every day of the fact that life is very often not as long as you think, that the hours and minutes count. That five-minute conversations might matter a lot more than five-year plans. And when I was ill people were suddenly so much kinder – kind in a way we all should always be.

A recognition of death is often twinned with a powerful thirst for life. So what happens when we strive to live forever, and how would the postponement of death affect the way we live? Would it change?

Great outrage was directed at the scientists who published a paper in Nature this week, in which they argued that our life expectancies, after rising dramatically since 1900 or so, have plateaued and are not likely to progress much further.

One of the authors, Dr Jan Vijg from the Albert Einstein College of Medicine in New York, thinks we have already reached the top limit of human longevity: "From now on, this is it. Humans will never get older than 115."

What they found was that the survival age of older groups had increased for the past century but levelled out in 1980 – at roughly 99. Since then, the increase in the age limit has been fractional.

We are unable to fully repair the damage to our DNA done by the process of ageing and as the scientist, and Vijg puts it: "At some point everything goes wrong, and you collapse." (Critics say the scientists forgot to factor in future developments in medicine.)

 Have we really grappled with a world full of centenarians?  How would we live?

A central question in the memoir of a brilliant neurosurgeon dying of brain cancer, When Breath Becomes Air, is how differently the author Paul Kalanithi​ would live according to how long he thought he had – two months, two years or two decades. 

And if discrepancies in access to medical treatment are already yawning chasms, how can we ensure that a bid to prolong ageing is not just a space race between billionaires?  Life expectancy in some African countries still hovers around 50: Sierra Leone, Angola, Central African Republic, Chad, Ivory Coast are all between 50 and 53 years.

Research studies show desire for longer life fades as people age, and that the wealthier hanker for it in a way poorer people do not.

What was missed in all the hue and cry about Vijg's research is he still thinks there is a strong chance we can improve our health span, which is surely the best outcome.

The thirst to live and endure is understandable. But an understanding of our own mortality can often make living sharper.