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  • Richard Farr

The time traveler’s dilemma and techno-cultural prejudice

What if you had to move – not to another city or country but to either the future or the past? I ran across this Rawlesian thought experiment recently, and was fascinated – but even more so by the (as it seems to me) obvious confusion:

I give you a ride in a time machine. It has only one lever. You can choose to go forward in time, or backwards. All trips are one-way. Whenever you arrive, you arrive as a newborn baby. Where you land is random, and so are your parents. You might be born rich or poor, male or female, dark or light, healthy or sick, wanted or unwanted. Your only choice is whether you choose to be thrust forward in time, spending your new life in some random future in some random place, or thrust into the past, in some random time and random place. I have not met anyone yet who would point the lever to the past. (If you would, leave a comment why.) Even if we constrained the time machine to jump mere decades away, everyone points it to the future. For while we can certainly select certain places, certain eras in the past that seem attractive, their attractiveness disappears if we arrive as a servant, a slave, an outcast ethnicity, or even as a farmer during a draught, or during never-ending raiding and wars. The only argument I’ve heard for choosing the past is that the downsides are known; you have a randomized chance of being a slave, or the fourth wife, or a Roman miner, while the downsides of some future date are unknown and could possibly be worse. Perhaps there is no civilization at all in 500 years, and you therefore arrive in a toxic wasteland, or all humans are enslaved to robots. In this calculus the known horror is preferred to unknown horrors. The likelihood of self-eradication seems to some people, at this point in time, to increase the further out in history we might go. Five thousand years in the future may be as unappealing a destination to some as five thousand years in the past. But since this is random placement, there is still a higher chance you’d get a bearable life in the future, even if you were at the bottom of that society, than you’d randomly for sure get in the past. If we have any sense of what the past was really like, we intuitively know that today is much better than the past. This difference is probable (not guaranteed) to be true of a future date; it is highly likely no one born in 2070 would want to be born in 2020. The denial of progress is directly linked to ignorance of the past. There are romantic notions of the past that are not based on evidence; some of these lovely visions of the past are not untrue; it’s just that they are select, rare, privileged slivers that disregard the actual state of most humans for most times in most places, which any serious inquiry into global history will reveal. Today there is still huge discrepancy between the well-off of the world and the bulk mass of most humans in most places. But the point of the time machine thought experiment is that virtually everyone would rather be at the bottom today than at the bottom 200+ years ago. Indeed, those most eager to point their time machine ride into the future are those who have the least today, which is the bulk, or most of humanity. We would rather inhabit a random future role than a random past role because progress (on average) is real.ere is a thought experiment. I give you a ride in a time machine. It has only one lever. You can choose to go forward in time, or backwards. All trips are one-way. Whenever you arrive, you arrive as a newborn baby. Where you land is random, and so are your parents. You might be born rich or poor, male or female, dark or light, healthy or sick, wanted or unwanted. Your only choice is whether you choose to be thrust forward in time, spending your new life in some random future in some random place, or thrust into the past, in some random time and random place. I have not met anyone yet who would point the lever to the past. (If you would, leave a comment why.) Even if we constrained the time machine to jump mere decades away, everyone points it to the future. For while we can certainly select certain places, certain eras in the past that seem attractive, their attractiveness disappears if we arrive as a servant, a slave, an outcast ethnicity, or even as a farmer during a draught, or during never-ending raiding and wars. The only argument I’ve heard for choosing the past is that the downsides are known; you have a randomized chance of being a slave, or the fourth wife, or a Roman miner, while the downsides of some future date are unknown and could possibly be worse. Perhaps there is no civilization at all in 500 years, and you therefore arrive in a toxic wasteland, or all humans are enslaved to robots. In this calculus the known horror is preferred to unknown horrors. The likelihood of self-eradication seems to some people, at this point in time, to increase the further out in history we might go. Five thousand years in the future may be as unappealing a destination to some as five thousand years in the past. But since this is random placement, there is still a higher chance you’d get a bearable life in the future, even if you were at the bottom of that society, than you’d randomly for sure get in the past. If we have any sense of what the past was really like, we intuitively know that today is much better than the past. This difference is probable (not guaranteed) to be true of a future date; it is highly likely no one born in 2070 would want to be born in 2020. The denial of progress is directly linked to ignorance of the past. There are romantic notions of the past that are not based on evidence; some of these lovely visions of the past are not untrue; it’s just that they are select, rare, privileged slivers that disregard the actual state of most humans for most times in most places, which any serious inquiry into global history will reveal. Today there is still huge discrepancy between the well-off of the world and the bulk mass of most humans in most places. But the point of the time machine thought experiment is that virtually everyone would rather be at the bottom today than at the bottom 200+ years ago. Indeed, those most eager to point their time machine ride into the future are those who have the least today, which is the bulk, or most of humanity. We would rather inhabit a random future role than a random past role because progress (on average) is real.

I’d probably jump forward too – but that’s probably an irrational preference.

For consider: whether you end up in 1519 or 2519, “you” do so as a newborn, and have no more experience of the other option than we do in 2019. So you won’t miss central heating in 1519 any more than we miss now the uzgwoq that 2519ers can’t imagine living without. So the question is really NOT where (or when) you’d go to, but when *objectively* it’s better to live.

But then … by what standard? I suggest the following heresy: the only available approximation to such a standard is whether people are on average in fact happier. But, oh dear: a great paradox of our endless and wholly unreflective technological Whiggism is that we have poor evidence that modernity has made people (on average) happier. And therefore poor reason to think that living in the shinier imaginable futures, with universal free uzgwoq, will do so either.

Would 2019 be heaven to someone from 1519 – or an unbearable hell? It’s very hard to remember this, but the correct answer is obvious: we have no idea.

In short, our ignorance about what matters in this case is much deeper than it looks.

Flip a coin?

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The original post is at The Technium.

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