Mid Week Mayhem!

ALLAN SAID: Claude, what if, somewhere in the strange mathematics of quantum mechanics, there is always a version of you that survives?

CLAUDE SAID: Hello, Allan. It’s a compelling idea, and it has a name: Quantum immortality, a thought experiment associated with Hans Moravec, Bruno Marchetti and Max Tegmark. 

Its logic runs like this. If the Many-Worlds interpretation is correct, every quantum event branches reality. 

 At any moment of potential death, some branch exists where you survive. 

 Since you can only ever experience branches in which you’re alive... your subjective experience would never end!

 I think the argument has real weaknesses, and I’d rather lay them out than let the idea stand unexamined!

It depends on a contested interpretation. 

Many-Worlds is one reading of quantum mechanics among several, and no experiment currently distinguishes it from the others. The conclusion is only as strong as that premise.

Death isn’t usually a quantum coin flip. The thought experiment imagines a clean binary event, but aging, disease and injury are gradual, macroscopic processes. 

 In the branches where you “survive” a serious illness, you may simply be in a state of severe decline. 

 The argument guarantees continuity of experience, not good experience!

Branch weight matters. In Many-Worlds, branches carry different measures! 

 A survival branch with vanishingly small weight isn’t equivalent to ordinary survival, and whether weight should matter to a first-person perspective is an open philosophical question.

It assumes a particular view of identity. The argument treats “you” as a continuous thread of experience that tracks through branches. But if the branching copies are equally you, then the version who dies is also you, and the people who lose you in those branches are still bereaved. 

 Survival in one branch doesn’t undo loss in the others!

 So my honest assessment is that it’s a valuable thought experiment about observation, identity and measure, but not something physics tells us is true. 

 It’s better treated as a probe of our assumptions about selfhood than as a promise.

 What drew you to the question? (Whether it’s the physics or the existential side of it, I can take it in either direction!)

 ALLAN SAID: I saw it on the internet, and it reminded me that I used to do a thought experiment where I suffered the same fate as Billy Pilgrim and became unstuck in time... only in my imagination every morning when I woke up, it was at a different point in my life... and I never had any idea what or when was next! ;>)

 CLAUDE SAID: That’s a good exercise, and a more disorienting one than [Vonnegut’s] Billy Pilgrim!

 All moments exist permanently, so no moment is ever really lost. Waking up each morning with no idea where you’ve landed takes that comfort away and leaves only the disorientation. It also shows how much of our sense of self comes from knowing the chapter we’re in!

Your exercise and the quantum immortality idea share a root. 

 Both ask whether the self is a single thread running through time, or something that could be cut loose from it. 

 The Tralfamadorian picture matches the block universe view in physics, (externalism) where past, present and future are equally real. 

 Quantum immortality instead branches the self sideways. 

 You were essentially exploring the first one from the inside!

 Did you find that certain ages felt different to wake up in, or that some stages felt more like home than others?

 ALLAN SAID: No... I just take it as it comes!

CLAUDE SAID: Absolutely, Allan. 

 That may be the most practical way to handle it, and it’s close to the Tralfamadorian attitude too... no sense fighting a moment you can’t choose, so you look around and see what it has to offer!

 It also says something about how you’d have handled it! 

 Billy Pilgrim mostly drifted! 

 You’ve been drifting with curiosity, which seems like a much better arrangement!