Wednesday, May 16, 2012

Time's Arrow

This blog has, for the most part, been confined in both space and time. In space to the Solar System, which we can reach without extraordinary difficulty (including extraordinary travel times), at least for a fairly generous definition of 'extraordinary.' In time to the Plausible Midfuture, a historical era I have not really tried to pin down.

Mainly I think of it as starting on the far side of current planning horizons, and extending to ... well, whenever is far enough into the future that our own era has faded off into the distant past. More or less, the era 2050-2300 might do well enough, though - especially at the far end - mere chronology is not really the point.

From a technological perspective, you might think of the midfuture this way: On the near edge, it is beyond what we are now specifically planning or building for. A fairly simple and robust concept, I think (so long as you don't examine it too closely).

At the far edge?If the Industrial Revolution continues at broadly the pace it has so far, 200 years takes us about as far into the future as the first successful steamboat lies in the past. The economic level will be about ten times higher than ours. If technological progress keeps chugging along past that point the world will become increasingly hard for us to understand or even recognize. It may not be transhumanist or a Singularity, but it will be strange.

On the other hand, if technology reaches the limits of the feasible, the world will become strange in a different way, deeply unlike the world we have experienced for the last two centuries. It will be a world in which not much changes, in terms of human capabilities, in the course of a generation or even a lifetime. And it will be a world in which the economic pie (though perhaps large by our standards) is no longer growing significantly. The argument about how to divide it up will therefore be much more fraught.

Such are the reasons, broadly, for confining most discussion here to the Plausible Midfuture.

But of course the future will - we hope! - not come suddenly to an end in 2250 or 2300, or any such date. Only on one occasion have I looked much further into the future, 40,000 years to be exact. (On one other patriotic occasion I glanced toward the 'Murrican future of 2700. But that is still only a slightly generous midfuture.)

The more distant future was brought to mind by (first-time!) commenter John G. He rescued last post's comment thread from a contemporary political argument (these never seem to change any minds) by bringing up a really long time scale. In five billion years or so the Sun will leave the main sequence and become a red giant, incinerating the Earth. Unless we go into space our descendents will presumably be incinerated along with it.

As an immediate argument for pushing along the space program I think this fails an urgency test. We have plenty of time! But in larger perspective ... well, it raises the question of larger perspectives.

Imagining 40,000 years of future history is a challenge. Imagining five billion years of it is staggering.

But one fundamental question emerges almost right at the beginning: What are the limits of the possible? My own general assumption has been that they are vast, and that it could take us a very long time to approach them. Science and technology have - so far - tended to advance by saltation, AKA leaps. This was the premise behind T S Kuhn's The Structure of Scientific Revolutions, which bears the burden of having contributed 'paradigm change' to the vocabulary of business jive.

By this argument, the scientific and industrial revolutions might well peter out in another century or two, reaching equilibria at which further progress is so difficult that it more or less stalls. All the locally low-hanging fruit will have been picked. At some later date, gradually accumulated knowledge and skills could trigger another era of revolutionary advances. But we have no real way to guesstimate how many centuries or millennia the intervening period of stability may last.

This is how I would approach a future history, for the sake of keeping the spires & togas era of godlike powers safely in the remote future.

There are, however, two alternative possibilities - or maybe three. One - the most familiar - is the Singularity argument. Scientific and technical progress will not just continue, or even accelerate: It will explode, catapulting us - or our replacements - into an unimaginably remote future in the course of a few decades.

A second alternate possibility is that progress will continue at roughly the rate it has since Watt's steam engine: A tenfold increase in technical capabilities and economic level, give or take, for each 200 years. By Singularity standards this is tediously sluggish. But it means a millionfold increase by the year 3200. In cosmic perspective this is indistinguishable from a Singularity.

A third alternate possibility is that, in fact, we are reaching the limits of both knowledge and progress. Yes, the computer industry has given us smartphones and Google, but cars and airplanes have changed little in overall configuration and performance since midcentury. Once you learn how to do things, you become pretty good at them pretty quickly. And after that point it is mostly just refinement.

As a loose analogy, the Age of Exploration lasted only a few centuries, and ended when there was not much left on Earth to explore. A world map of 1500 has mostly blank space or pure guesswork. A world map of 1600 looks kinda sorta familiar, and by 1800 - when the Industrial Revolution was just taking off - the world map had been mostly filled in.

There is still plenty of universe to explore, but our instruments for doing so may be broadly limited to the sorts of technologies I've projected in the Plausible Midfuture. Getting into space against the pull of Earth's gravity may be just inherently very difficult. Once you get there, speeds of dozens or even hundreds of km/s are pretty readily attainable. Speeds reaching an appreciable fraction of c are problematic, and FTL is a tower of wishful thinking erected atop a grain of physics speculation.

Or not.


The post title is swiped from a Clarke story, though I don't really recall the story itself, and only when I googled did I learn that it is also the title of a Martin Amis novel and a Trek: TNG episode.

The image, from a poster site, shows pharaoh Rameses III hunting with a bow.