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As I understand it, consciousness-causes-collapse (CCC) theories, although not very popular among physicists, have not been falsified (e.g. https://arxiv.org/abs/1609.00614).

This confuses me because my understanding of wavefunction collapse is that, at least some of the time, it must happen without a conscious observer present. The quantum Zeno effect, for instance, involves frequently "measuring" a radioactive element and thus preventing it from decaying. Each of the "measurements" in a quantum Zeno experiment are done by the measurement device (pulses of UV light).

While it is the case that no observer will become aware of these measurements until someone is conscious of them, it is still the case that a whole succession of collapses have occurred between conscious observations. This succession of collapses have had a measureable effect on the time evolution of the radioactive element, and the system would look different depending on whether they occurred or not.

My question is then: how do you maintain CCC theories on light of this? Doesn't this mean a single conscious measurement must be able to collapse a whole chain of multiple dependent collapse events far into the past? Or can it still be maintained as a single collapse at the moment of "measurement"? Or am I completely off base?

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  • $\begingroup$ "my understanding of wavefunction collapse is that it happens all the time without a conscious observer present " --- How do you know? $\endgroup$ – WillO Aug 4 '19 at 4:11
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    $\begingroup$ Well, I assume the physical reality described by a system that has undergone multiple collapses at different times can look different to one that never underwent collapse. Is this not true? $\endgroup$ – Francis Dillon Aug 4 '19 at 6:20
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    $\begingroup$ These days, CCC is mostly popular with quantum mystics, like Amit Goswami; serious physicists don't want to be associated with that kookiness. ;) $\endgroup$ – PM 2Ring Aug 4 '19 at 10:38
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Two major reasons: there are not generally accepted, testable definitions for either consciousness or wavefunction collapse. If there were such definitions, it would probably be possible to falsify or verify those theories.

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  • $\begingroup$ How could they be falsified? When you see what you expect to see, your results are verified by default. $\endgroup$ – David White Aug 4 '19 at 4:48
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    $\begingroup$ @DavidWhite,is that a serious question? $\endgroup$ – S. McGrew Aug 4 '19 at 4:59
  • $\begingroup$ There is no testable definition for consciousness, but wavefunction collapse is certainly a well-defined idea -- it represents a collapse of the probability (amplitude) distribution representing your knowledge of a system. $\endgroup$ – Abhimanyu Pallavi Sudhir Aug 4 '19 at 5:20
  • $\begingroup$ The very idea of wavefunction collapse has been debated from the beginnings of quantum mechanics. The History and Context section of the Wikipedia article [en.wikipedia.org/wiki/Wave_function_collapse] explains this pretty well. Measuring "the probability distribution representing your knowledge of a system" is not physically possible. $\endgroup$ – S. McGrew Aug 4 '19 at 13:17
  • $\begingroup$ @S.McGrew, you already know that if you take a measurement (look at some quantum mechanical entity), you will get a definite value rather than a probability distribution. $\endgroup$ – David White Aug 4 '19 at 18:05
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If you accept positivism, it becomes obvious that "consciousness causes collapse" cannot possibly be distinguished experimentally from the Copahangen principle as long as you accept that you are conscious.

This "interpretation" makes claims about the knowledge of another (non-conscious) observer, claiming that it does not alter the state of other systems. But this is fundamentally a metaphysical claim -- it's like asking "what if my red is your blue and my blue is your red?" Whatever your metaphysical belief on whether a non-conscious observer "already" caused a wavefunction collapse, your knowledge only changes when you observe the system, be it of that non-conscious observer.

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  • $\begingroup$ Ok, so my follow-up is: doesn't this require that the conscious "measurement" causes a whole chain of collapses extending far into the past? I'm assuming a physical system with no collapses will look different to one that has had multiple collapses over time. $\endgroup$ – Francis Dillon Aug 4 '19 at 6:25
  • $\begingroup$ is this really so? en.wikipedia.org/wiki/Quantum_Zeno_effect $\endgroup$ – Wolphram jonny Aug 4 '19 at 13:53
  • $\begingroup$ @Wolphramjonny the Quantum Zeno effect is a good example. The atom is kept from decaying by repeated wavefunction collapses. These seem to occur without a conscious observer present. Obviously the atom would look different if it wasn't repeatedly "measured". How does CCC explain this? $\endgroup$ – Francis Dillon Aug 5 '19 at 0:24
  • $\begingroup$ that is what I am trying to figure out, lol. I used to agree with this answer, at least the math seems to say so. I might be misunderstanding what the zeno effect is though $\endgroup$ – Wolphram jonny Aug 5 '19 at 0:51
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    $\begingroup$ @Wolphramjonny Just write down the state vector for the combined system of the (not yet measured) "non-conscious" apparatus and the system being measured. This represents the "knowledge of the system according to an external observer". As you can see, metaphysical questions about the "knowledge of the apparatus" are not involved in the expression. $\endgroup$ – Abhimanyu Pallavi Sudhir Aug 5 '19 at 7:46

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