Time travel comes up frequently in science fiction, and some physicists think it might be theoretically possible, to some degree, within major constraints, at vast expense, between times that are in different universes. Frankly, my physics is rusty and I don’t have any useful contribution to make on how we might do physical time travel, nor on its potential. However, intelligence available to us to figure the full physics out will accelerate dramatically thanks to the artificial intelligence positive feedback loop (smarter machines can build even smarter ones even faster) and some time later this century we will definitely work out once and for all whether it is doable in real life and how to do it. And we’ll know why we never meet time tourists. If it can be done and done reasonable economically and safely, then it will just be a matter of time to build it after that.
Well, stuff that! Not interested in waiting! If the laws of physics make it so hard that it may never happen and certainly not till at least towards the end of this century, even if it is possible, then let’s bypass the laws of physics. Engineers do that all the time. If you are faced with an infinitely tall impenetrable barrier so you can’t go over it or through it, then check whether the barrier is also very wide, because there may well be an easy route past the barrier that doesn’t require you to go that way. I can’t walk over tall buildings, but I still haven’t found one I couldn’t walk past on the street. There is usually a way past barriers.
And with time travel, that turns out to be the case. There is an easy route past. Physics only controls the physical world. Although physics certain governs the technologies we use to create cyberspace, it doesn’t really limit what you can do in cyberspace any more than in a dream, a costume drama, or a memory.
Cyberspace takes many forms, it is’t homogeneous or even continuous. It has many dimensions. It can be quite alien. But in some areas, such as websites, archives are kept and you can look at how a site was in the past. Extend that to social networking and a problem immediately appears. How can you communicate or interact with someone if the site you are on is just an historical snapshot and isn’t live? How could you go back and actually chat to someone or play a game against them?
The solution to this problem is a tricky technological one but it is entirely possible, and it won’t violate any physics. If you want to go back in time and interact with people as they were, then all you need is to have an archive of those people. Difficult, but possible. In cyberspace.
Around 2050, we should be starting to do direct brain links, at least in the lab and maybe a bit further. Not just connections to the optic nerve or inner ear, or chips to control wheelchairs, we already have that. And we already have basic thought recognition. By 2050 we will be starting to do full links, that allow thoughts to pass both ways between man and machine, so that the machine world is effectively an extension of your brain.
As people’s thoughts, memories and even sensations become more cyberspace based, as they will, the physical body will become less relevant. (Some of my previous blogs have considered the implication of this for immortality). Once stuff is in the IT world, it can be copied, and backed up. That gives us the potential to make recordings of people’s entire lives, and capable of effectively replicating them at will. Today we have web archives that try to do that with web sites so you can access material on older versions of them. Tomorrow we’ll also be able to include people in that. Virtually replicating the buildings and other stuff would be pretty trivial by comparison.
In that world, it will be possible for your mind, which is itself an almost entirely online entity, to interact with historic populations, essentially to time travel. Right back to the date when they were started being backed up, some time after 2050. The people they would be dealing with would be the same actual people that existed then, exactly as they were, perfect copies. They would behave and respond exactly the same. So you could use this technique to time travel back to 2050 at the very best but no earlier. And for a proper experience it would be much later, say 2100.
And then it starts to get interesting. In an electronic timeline such as that, the interactions you have with those people in the last would have two options. They could be just time tourism or social research, or other archaeology, which has no lasting effect, and any traces of your trip would vanish when you leave. Or they could be more effectual. The interactions you have when you visit could ripple all the way back through the timeline to your ‘present?’, or future? or was it the past when you were present in the future? (it is really hard to choose the right words tenses when you write about time travel!!). The computers could make it all real, running the entire society through its course, at a greatly accelerated speed. The interactions could therefore be quite real, and all the interactions and all the minds and the rippling social effects could all be implemented. But the possibilities branch again, because although that could be true, and the future society could be genuinely changed, that could also be done by entirely replicating the cyberworld, and implementing the effects only in the parallel new cyber-universe. Doing either of these effectual options might prove very expensive, and obviously dangerous. Replicating things can be done, but you need a lot of computer power and storage to do it with everything affected, so it might be severely restricted. And policed.
But importantly, this sort of time travel could be done – you could go back in time to change the present. All the minds of all the people could be changed by someone going back in the past cyberspace records and doing something that would ripple forwards through time to change those same minds. It couldn’t be made fully clean, because some people for example might choose not to have kids in the revised edition, and although the cyberspace presence of their minds could be changed or deleted, you’d still have to dispose of their physical bodies and tidy up other physical residual effects. But not being clean is one of the things we’d expect for time travel. There would be residues, mess, paradoxes, and presumably this would all limit the things you’d be allowed to mess with. And we will need the time cops and time detectives and licenses and time cleaners and administrators and so on. But in our future cyberspace world, TIME TRAVEL WILL BE POSSIBLE. I can’t shout that loud enough. And please don’t ignore the italics, I am absolutely not suggesting it will be doable in the real world.
Fun! Trouble is, I’m going to be 90 in 2050 so I probably won’t have the energy any more.