3134: Wavefunction Collapse

2025-08-28T19:57:52Z

2600:387:4:803:0:0:0:86: /* Explanation */ context: interpretations of QM, waveform collapse, mention title text in explanation

{{comic
| number = 3134
| date = August 27, 2025
| title = Wavefunction Collapse
| image = wavefunction_collapse_2x.png
| imagesize = 656x272px
| noexpand = true
| titletext = Wavefunction collapse is only one interpretation. Under some interpretations, graduate students also have souls.
}}

==Explanation==
{{incomplete|This page was created BY A SOUlFUl PARTICLE DETECTOR. Don't remove this notice too soon.}}

There are multiple {{w|interpretations of quantum mechanics}}, i.e., stories to help us gain intuition. Some of these involve {{w|wave function collapse}}, where multiple mathematically possible states resolve into a particular state.

Quantum mechanics is commonly explained by saying that observation can cause change in the system, as in the {{w|Schrödinger's cat}} and {{w|Elitzur–Vaidman bomb tester}} thought experiments.
A physical example is the {{w|Double-slit experiment}}, where if the apparatus interacts with the photons, such that it indicates which slit photons go through, you get a different pattern of light, compared to an experiment where this is not detected.

The use of the word "observation" causes a bit of confusion about the nature of these experiments, as some people assume that ''human'' observation is what causes this, and conclude that humans must be “special” (more so than we already are to study science in the first place) if our observation is what causes quantum effects to resolve. In actuality “observation” refers to detectors. Any interaction which indicates the presence of a "particle" affects the system, and any quantum effects or mechanics will have already resolved before a human comes along to record the results. While the idea that {{w|Consciousness causes collapse}} was considered seriously by earlier physicists such as Wigner, it is now very unpopular.

This comic presents three possible responses to the question: "does my consciousness affect the universe?" The 'Bad' option shows Cueball telling his student that everybody has a soul, and their individual consciousness affects reality in some way. The 'good' option shows Cueball telling his student that consciousness doesn't play a role at all, and that it is 'just a physical measurement'. The 'chaotic' option shows Cueball apparently observing that the wave function collapses only when ''he'' looks at it, because he is special in some way (in this case, Cueball is a professor while Hairy is the undergraduate student).

The title text continues the chaotic option. Graduate students are intermediate between undergraduate and professors. It is unclear whether graduate students can cause waveform collapse, and therefore have souls.

In both [[660: Sympathy]] and [[803: Airfoil]] there are situations where three possible replies are given. And, just like here, the first two are simply wrong and right (although in the other order). The last, in those, is Very Wrong: as opposed to the Chaotic here, but it seems like this comics interpretation called chaotic could also have been labeled very wrong, and [[:Category:Unsolved Problems|some other similar setups]] escalate to a Cursed third scenario. So this is one of the generally recurring joke-payoffs, here on xkcd.

==Transcript==
{{incomplete transcript|Don't remove this notice too soon.}}

:[Hairy is sitting behind a desk with a hand on the table and Cueball is standing next to him.]
:Hairy: If the wavefunction only collapses when I observe it, does that mean my consciousness affects the universe?

:[A panel with the caption "Bad:" on the top left, zoomed into Cueball's head]
:Cueball: Yes, quantum entanglement proves that we all have souls.

:[The same scene with the caption "Good:"]
:Cueball: No, consciousness plays no role here. Its just physical measurement.

:[The same scene with the caption "Chaotic:"]
:Cueball: No, the wave function collapses when '''''I''''' look at it because I'm a full professor.
:Cueball: It won't collapse for an undergraduate.

{{comic discussion}}<noinclude>
[[Category:Comics featuring Hairy]]
[[Category:Comics featuring Cueball]]

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3134: Wavefunction Collapse