What would it be like to live 500 years? Healthy years, of course; no one wants to live 500 years in a coma on a respirator. But reasonably healthy all that time? That would be awesome! Few of us actually want to die. Extra time – that much extra time! – would be truly wonderful. It would be a gift ... one in which, last week, the president and managing partner of Google Ventures announced he would invest $425m.

But then I ask myself, who exactly will be living these five centuries? It’s easy to speak in glowing terms of medical breakthroughs that will slow or reverse aging. But often when we talk of technological and scientific breakthroughs we forget that those proclaiming their merits – scientists, futurists, academics or doctors of one stripe or another – are often thinking of their own, personal lives, and the lives of those they’re surrounded by. But their normal is not everyone’s normal. So if you ask me “What is it like to live 500 years?” I want to know who’s asking.

Right here, right now, we produce more than enough food to feed everyone on the planet, but people still starve. It’s not just a question of available resources and not just a question of capability. If you can’t access it, all the resources in the universe won’t do you any good.

Would living these extra centuries be a right, something any human being is entitled to? Or would it be a luxury?

When I was young (I am dating myself here) it was entirely legal for a hospital to turn someone out who couldn’t pay, even if that person would likely die. That’s no longer the case, but the discussion surrounding healthcare reform implies that some Americans think of medical treatment as a privilege one ought to earn, not something that ought to be given as a matter of basic humanity. I could see that pendulum swinging back and forth over the years.

I wouldn’t take access for granted. For example, if life extension would require taking time off work for treatments, would your employer be obligated to give you enough leave, or would you be faced with choosing between your job or your life?

Those of us who won’t be able afford it will die so very young by comparison to those quincentennials, won’t we? And perhaps people will say “it’s a shame but surely they should have made better choices?”. (It’s terrible to see how badly some people choose their parents.) The poor who scrape and save and sacrifice and somehow manage it – that will only “prove” that they weren’t really poor and didn’t really need any support or help, or it will demonstrate the same sort of extravagance that impoverished them to begin with!

Will people whisper behind their backs, or say aloud on the evening news, that they’re wasting valuable medical resources just to live centuries in poverty – maybe even sponging off the public by taking food stamps? And what if you have some sort of disability that - by their lights - makes your longer life a waste of time and resources? Will those whisperers or talking heads ever stop to realize they’ve just said society would be better if you died? Would they be ashamed to realize that?

The ability to live for five hundred years would be an incredible gift. But I greatly fear it would be a gift only for the wealthy – one that might greatly widen the gap between those with access and those without.