Comments on: “How Many Lives has the Higgs Boson?”

By: Mike

Mike — Sun, 15 Nov 2009 14:37:13 +0000

What would happen in a time travel world if someone tried to go back in time to kill their grandfather? They’d fail.

Hmm. I have that you (i.e. Tim) can and cannot kill his grandfather, depending on the facts that you take to be relevant. Some of those are compossible with Tim’s success, some aren’t; you can reasonably choose either one.

By: Jamie Dreier

Jamie Dreier — Sat, 07 Nov 2009 14:19:59 +0000

You should be suspicious. It's a hoax. Here's what really happened.

By: DjR

DjR — Sat, 07 Nov 2009 01:12:29 +0000

I quote from an email about this from my mate John Price, who says

My point is just that Lewises point is that more probably we find ourself living on the higher intensity branches – but not on branches where we are dead. So for any crunch, after crunch time we may find ourself alive on a branch that from a statistical point of view, looks very low-intensity. Barring coincidences, that’s when on the high intensity branches we are dead, and (for us) they are culled and we are here —->.

(John continues): I see no way that this process will retrofit any culling of branches to the past? Branches on which CERN persists with LHC and branches on which it quits are for the time being both still branches on most of which you are alive, I hope? Nu?

By: Brian Weatherson

Brian Weatherson — Fri, 06 Nov 2009 23:19:16 +0000

I’m starting to get very suspicious about all of this…

By: srs

srs — Fri, 06 Nov 2009 23:10:33 +0000

Hm: http://www.timesonline.co.uk/tol/news/science/physics/article6905250.ece

By: dtlocke

dtlocke — Mon, 19 Oct 2009 23:03:07 +0000

Lewis’s argument rests on (1), no?

1. I should spread my expectations for what will be the case at t exclusively over possibilities in which I have experiences at t.

That seems false to me, even if the Everett Hypothesis is true. Of course, (2) is true:

2. I should spread my expectations for what I will experience at t exclusively over possibilities in which I have experiences at t.

But (2) is trivial. (2) is equivalent to

3. I should spread my conditional expectations Cr(P given that I have experiences) for what will be the case at time t exclusively over possibilities P in which I have experiences at t.

And (3) is not equivalent to (1).

Anyway, that’s what I’ve always thought about Lewis’s paper, but I’ve never spoken to anyone about it. Am I missing something?

By: Alan

Alan — Sat, 17 Oct 2009 02:46:20 +0000

If Higgs bosons are so nefarious, surely they wouldn’t confine their conspiratorial powers of temporal sabotage to just physical events—clearly we can’t form consistent ideas about them and can’t see that inconsistency since that would guarantee that no apparatus could be thus physically constructed that would produce them. Not just many-worlds then, but many-minds…

By: Huw Price

Huw Price — Wed, 14 Oct 2009 21:12:11 +0000

It gets better. Suppose A’s device produces Higgs bosons when the temperature of B’s beer (wine cellar, planet) rises above comfortable levels. It is tempting to think that A has done B a big favour, by guaranteeing him a comfortable future, with no effort on his part. (This is Euan Squires’ quantum Russian roulette.)

The nice thing about the Higgs boson, on your hypothesis, is that it seems to be solving Lewis’ tails problem, by disfavouring branches in which survival is unpleasant.

By: Brian Weatherson

Brian Weatherson — Wed, 14 Oct 2009 12:11:10 +0000

The moral psychology of the Everett hypothesis (should we be mourning, worrying etc) is kind of fascinating actually. If I know measure 0.99 of my ‘branches’ are going to be trimmed, I don’t think I feel particularly worried about it.

Indeed, the ethics appropriate to agents in an Everett world are tricky.

If A sets up a device that has a 0.8 chance of killing B, has A done anything wrong? You might think no – after all, B will see that the device doesn’t work. But that’s too simplistic. B’s friends will see him killed in 80% of the branches, and what A does is terrible to them.

But what then if A sets up the device to kill all of B’s friends, and all of their friends, and so on as well? Then has A harmed anyone? It’s kind of hard to say.

By: djc

djc — Wed, 14 Oct 2009 11:57:01 +0000

Don’t forget the (very surprising) failure of the SSC. That counts for at least another failure or two. My credence in many-worlds plus collider-kills has been boosted by at least a factor of 1000 or so from its prior. If this goes on, I’m not sure whether we should be mourning all our dead counterparts or worrying about all the deaths that face us in the near future. But I suppose that we should at least be grateful to Everett for the survival mechanism.