Jennifer Tullet answered on 10 Jan 2014:
I really don’t think we will ever “live forever” and this is not what the majority of scientists studying ageing and lifespan are aiming for. This is a very good question though and something that is very important to think about even when we are talking about extending lifespan by a few years as there would be a lot of social and ethical implications to this.
There is an awful lot to say about this and I’m sure Penny can add more but here are a couple of points.
I went to an excellent talk in December by an American scientist called Rich Millar and he pointed out that if you look at what has been done in model organisms (worms, flies, mice etc…) the biggest extensions in lifespan seen with modifying the genome or other environmental interventions like dietary restriction and translate that to human lifespan we would be looking at an extension of about 40 years i.e. living till we were 140. So this would be a big increase but by no means living forever!
The most important point however is that scientists really want to make people live healthier lives. From what we know about ageing, changes to the genome that increase lifespan also protect and improve against the onset of lots of nasty diseases e.g. cancer, Huntington’s, Alzheimers. So the key thing is that by studying the ageing process as a whole we can improve the pathology of all these diseases together and improve the health of the population!
Penelope Mason answered on 10 Jan 2014:
I think Jennifer’s highlighted all the most important points, but this really is a huge area! I have some additional points ; ). Living forever really means being immortal. Rather than going on about how difficult it would be to make your body immortal (and it would be – we’ve discussed this a bit more in a previous question: Is it possible to rejuvenate?) I just wanted to highlight one thing – biological immortality means having the capacity to regenerate all your cells. This would include your neurons i.e. the cells of the brain, so as they were replaced and remade, you would basically be losing/changing the bit of the body containing ‘you’.
We don’t do this now – you die with the same neurons you were born with (it’s largely the connections that change as you grow and learn). We don’t yet know enough about how consciousness is stored to know exactly what this would mean, but I imagine at the very best this would mean that over time you lost memories – not just conscious memories, but all the unconscious stores that make up your personality. You therefore would be likely to change subtly over time, and would probably have to relearn things. Would this be a problem? That’s a big question, and there are obvious ethical and even spiritual concerns which aren’t really for me to articulate.
However, perhaps we could find a way to keep the same cells alive indefinitely and sidestep this question. I would think that this would be much harder and would have to involve some level of medical intervention rather than relying on genetic mechanisms. And whilst the plausibility of having a body that regenerates is low but there are examples to be found in the world (c.f. Jennifer on the rejuvenation q), immortality with the need for invasive mechanical intervention starts to look like science fiction. I would never rule anything as impossible, but we would be talking quite far in the future here.