Fukuyama has it half right
In the The Long Arc of Historical Progress Yoshihiro Francis Fukuyama argues for structure over agency in long term human future. That is he argues there is a guiding shared goal that makes an ever better life for humanity probable. As opposed to a battle of agency where the fate of humanity is fought for over and over by individual action.
Up until now Fukuyama has a point — the long arc shows an ever increasing human population and actors that encouraged that goal have, by definition, drowned out those that did not.
The goal of arriving at 7 billion humans on the planet structurally benefited from the ever increasing technology that made it possible. Or to put it another way humans popped out of our evolutionary origins as creatures destined to dominate the earth.
But as the U.N. projections above make clear there is nothing about human design that guarantees we all continue to work toward a shared goal of ever increasing population. Our attempts at further numerical domination might even end within the lifetimes of those alive today in 2022.
If humanity follows the U.N. green or orange lines then the arc of humanity becomes more difficult to define. Life span?
Adopting life span as a metric all but removes the obvious “arc of humanity” because ignoring infant and childhood mortality, hunter gathers can live as long as 2022 humans.
If you use infant and childhood mortality to define progress then humanity still has some work to do but again some people alive today might see a mission accomplished moment.
Going back to life span, or health span as it is more accurately defined for this purpose, what if our science could advance to create a true health span arc? Is this a goal that humanity could unite behind?
Maybe but first we have to solve the “Putin problem”. In a world where everyone is waiting for a genocidal dictator to die, giving people considerably more time in the prime of their lives is dangerous. On the other hand if humans could live considerably longer then recruiting for the kind of war being fought in the Ukraine could be much more difficult.
The other problem is that a health span goal might lose much of the structural support that increasing human population enjoyed. Humans might not be as geared for dramatically longer lives as they were for numerically dominating the planet.
First there are memory issues — can a person healthily living well beyond a 100 years even still remember his childhood? We are already becoming more and more dependent on technology to record our lives and past a certain age access to early memories might rely completely on digital storage.
Next there are purpose issues — the amount of time required to raise a child would remain constant. Would a long lifer continue to have children throughout the extended prime years? Would it grow boring?
Nor does conquering space do anything more than muddy the arc of history waters. Conquering earth has been anticlimactic. There is no reason to assume that conquering a second or third world will be very thrilling.
Fukuyama has it half right because their was an arc to history up until now. Where we go from here is unclear.