> One of the things I thought was amazing is that if you solve cancer, you’d add about three years to people’s average life expectancy ... it’s not as big an advance as you might think.
Thinking about improving total life expectancy in this way is not so useful because the large gains have already been made. For instance if no-one in the UK ever died between birth and age 60 it would only add 2-5 years to life expectancy at birth. 100 years ago the same situation would have added 20-25 years.
Perhaps more interesting would be to look at increasing the maximum life span, reducing the variance about the age of death, increasing the median age of death, or to consider the effect of curing cancer/other diseases on healthy life expectancy which I think could still be meaningfully increased.
Extended life is great, provided you solve the problems of over-population / birth rate exceeding death rate, and resource depletion. The carrying capacity of the planet is limited. Technology and ideas don't replace physics and chemistry.
So, can we radically extend life? Probably, with sufficient research.
But without solving the other two issues it raises huge problems. Unless of course we're talking a tiny immortal class controlling all the world's wealth and dwindling resources, and the rest with no access to it.
I am not suggesting we don't do this. Just highlighting that radical life extension poses unique problems which are an order of magnitude more serious to think through than regular medicine advances.
Technology and ideas do replace physics and chemistry when they improve efficiency. No comment, at the moment, on how that impacts the broader discussion.
Regarding the second half, I said I wasn't going to comment on the broader discussion.
Regarding the first, though, if we need to produce X horsepower for Y hours, then we can do it by using Z gas + Z' gas, or Z gas plus an idea for a more efficient engine. Ideas absolutely replace energy. They can't, so far as I can see, replace the last bit of energy, but we're nowhere near that.
That makes no sense. You can't just wish energy into existence with an idea. Efficiency gains aren't going to cut it with the energy consumption dynamics we have.
"You can't just wish energy into existence with an idea."
Yes, I said as much.
"Efficiency gains aren't going to cut it with the energy consumption dynamics we have."
Maybe not; that's a broader question. The point is that you can displace some need for energy with efficiency gains or alternatives. The more energy you're using, the more of a difference an idea can make, since ideas tend to mean proportional improvements in efficiency (though not necessarily large proportions).
Whether it's sufficient is a huge question that would require a lot more attention than I'm able to give this right now (which is why I've persisted in staying out of the mainline of the discussion here).
I think the answer to that in the part where the parent mentions physics and chemistry.
Until we can provably show that resources outside of Earth are available for human consumption, and within some range of feasibility; it's not valid to use the argument that the potential availability of said resources are a solution to the magnification of natural resource depletion on Earth caused by overpopulation.
Resources outside of Earth are available for human consumption provably. Alas, just at astronomical prices presently.
I understand that it is rather prudent to presume to act as if we are limited solely to Earth's resources - because we are right now - but to be reflexibly dismissive of space exploration as an avenue to be actively pursued to remedy such issues is simply not constructive.
Those prices are merely a proxy for the complexity and resources necessary to go and mine off-world resources. We need a highly complex economic and manufacturing system to remain in place for a long period despite increased pressures of resource depletion and overpopulation and the commensurate rise in instability; we need to use huge amounts of resources to create a space program - materials and energy; energy - all of the above requires huge petrochemical inputs which are finite and depleting rapidly. There was only 1 cubic mile of oil in the world and we're half way through it and what's left is being sucked out faster than ever before and is harder to get to (EROEI).
I'm not convinced we can provably show that the resources on Earth aren't capable of sustaining a great many more people, albeit with a significantly different style of living.
Of course we can. 90% of food production is based on fossil fuel inputs. Fossil fuels flow rates have plateaued and will move to decline. Because of the increased demand of population that decline will be rapid and increase quickly. When that happens massive amounts of people will starve. This will create huge social dislocations which make the maintenance of a complex system capable of space exploration unlikely.
But more basically you can add up energy consumption necessary to sustain any basic average standard of living sufficient to also maintain a functioning global economy, multiply it by population and compare it to the NOT proven reserves but net recoverable energy taking into account EROEI and it's not a good number. Google is your friend.
Further, this ignores other essentials such as topsoil depletion, fresh water and NPK inputs - NPK inputs are very limited in quantity, depleting rapidly and incredibly energy intensive to recover.
Exponential growth can't continue forever in nature.
No it doesn't assume no innovation. It's based on the fact that wishing for a magical elixir which will replace our dwindling resources is just that - wishful thinking.
Thinking about improving total life expectancy in this way is not so useful because the large gains have already been made. For instance if no-one in the UK ever died between birth and age 60 it would only add 2-5 years to life expectancy at birth. 100 years ago the same situation would have added 20-25 years.
Perhaps more interesting would be to look at increasing the maximum life span, reducing the variance about the age of death, increasing the median age of death, or to consider the effect of curing cancer/other diseases on healthy life expectancy which I think could still be meaningfully increased.