(also called "Von Neumann-Wigner interpretation")

I will give here my own exposition of this interpretation
of quantum
physics, according to which the collapse
(that is the transition from a "state of indetermination" between
several possibilities, to the exclusive realization of only one
possible outcome), is real and accomplished by the perception of
the measurement result by a conscious, immaterial observer; this
is the metaphysical source of the randomness that appears in
physical phenomena, which becomes the interface of expression of
free will when occurring in the brain.

A short version of this with other aspects is available in pdf: A
mind/mathematics dualistic foundation of physical reality, written for
the fqxi essay contest on the link between maths and physics
(where the discussion in comments helps to clarify a few points),
but unfortunately dominated by cranks.

Indeed, I guess the lack of available clear and coherent
expression of what this interpretation says, may be the main cause
why this interpretation seemed so unpopular and even rather
ignored until now in academic circles, before the lack of precise
arguments (together with, I would say, the presence of wrong
formulations and wrong arguments). I do not feel satisfied with
the way I saw it done by the few physicists and other people who
tried to express and support this idea of a fundamental role of
consciousness in quantum physics, such as H. Stapp and R. Penrose.
So, I understand why others did not take that view very seriously
in these conditions. What sense can be made of arguing about a
position that is not clearly expressed, or is expressed in a wrong
way ?

And of course, any link with religious views and other misuses by
New Age writers as a tool of illusion of scientificity to sell a
lot of spirituality books full of nonsense to a naive public, gave
it a very bad reputation in the eyes of scientists. This is quite
understandable. As I
commented here :

[My] combination of accurate metaphysics and accurate physics is quite unusual, and may be hard to follow for those who are not familiar with quantum physics, but I think it is necessary, otherwise physicists would again dismiss it a mere poetry having nothing to do with physics... not entering such details would mean telling nothing more than what others suggested before. And for now, as you can see in David Wallace's reviews of the different interpretations of quantum physics, the idea of a role of consciousness was not even included in the list. I'm not sure if he will do it in the future with my contribution but I understand that the vague calls for such an interpretation, or the strange tries of specifications for it, that I saw made by others until now, were not clear and coherent enough to seem deserving a place in some scientific debates on the topic... There are "problems" with the mind makes collapse interpretation, making it a "not very scholarly" topic of discussion. Namely : it only looks like a vague idea ; it cannot be put into equations or other rigorous definitions in order to check it for possible logical flaws ; many of the people who put it forward have no clue about physics and showed their ignorance of physics. The fact that such ideas were used to sell a lot of spirituality books with bullshit claims about how it can change your life by the power of positive hinking, is a very negative point for being taken seriously by physicists, and I perfectly understand such a reaction. One has to go past that and it is not obvious... And finally among the very few physicists who openly supported such an interpretation, the ones kept it trivial (e.g. Richard Conn Henry simply defines it as "the physical world does not exist", which, logically, does not leave any object to be discussed), the most famous one (Wigner) finally rejected it at the end of his life, others did it in wrong ways soon refuted by other works... which many scientists easily mistake as conclusive on the whole issue.

(and more...)

But the usual explicit objection to any idea of involving
consciousness in the foundations of physics, takes the form of an
appeal to Occam's razor : consciousness was not found to play any
fundamental role in the universe, but its presence can naturally
be explained instead as an emergent process by the Artificial
Intelligence thesis. However (and even if we ignore some
observations at the fringe of usual science, such as experimental
results of parapsychology), this nice picture of explanations
remains obscured
by two clouds (and more of course : divergences of the
standard model at high energies ; dark matter and quantum gravity,
that I would guess to be out of subject here):

- The hard problem of consciousness, a big matter of philosophical controversy;
- The measurement
problem

- Existence beyond mere mathematical existence: a purely algorithmic behavior cannot account for the notion that we "really exist" (that we have an authentic feeling of our existence, that morality makes real sense), because otherwise our existence would be purely mathematical, making any concept of probability devoid of any sense (since all possibilities equally exist mathematically, none of them can meaningfully be said more probable than another) and therefore in contradiction with the fact that such probability laws exist and have been verified. For more developments, see an essay by someone actually endorsing the view of the mathematical nature of the mind.
- Non-algorithmicity (the mind's behavior cannot be purely algorithmic): the reasoning power of the mathematician can know things such as the consistency of ZF, that cannot be proven out of any formal system that could be reasonably assumed to be his.

This argument was presented with a fine sense of humor by Sidney Coleman : Quantum mechanics in your face (starting from time 01:00:45) following an anecdote of Ludwig Wittgenstein wondering about the belief in geocentricism as a matter of "how things look like":

"Now, people say the reduction of the wavepacket occurs because it"looks likethe reduction of the wavepacket occurs. And that is indeed true. What I am asking you (...), is to consider seriously,what it would look likeif it were the other way round : if all what ever happens were causal evolution according to quantum mechanics. And what I have tried to convince you is that, what it looks like, is ordinary everyday life. Welcome home.

Indeed that use of Occam's razor looks quite elegant, and the
reasoning looks coherent, except, of course, that mathematical
arguments on probabilities always remain hopelessly circular
(since there is anyway no possible other basis for probabilistic
conclusions than circular arguments).

However it also looks like he overlooked the following : as long
as he does not include an answer to the hard problem of
consciousness in the picture, by which the presence of a conscious
observer looking at the world and having any subjective
impressions about it, is fully accounted for, how can he explain
the possibility for things to *look like anything at all* ?

The problem is, the AI concept
of "consciousness" does not look quite friendly with the
many-world's quantitative concept of "existence", in case
both are supposed to combine into a coherent concept of "conscious
existence".

Now without ignoring the elegance of Sidney Coleman's use of
Occam's razor, I'm going to shamelessly recycle it into a
different and even more radical use, that will explain more from
less. Here will be my question:

* What would the laws of physics look like, if physical things
were nothing else than their way of looking like something
when looked at by observers that cannot be themselves described
by any physical laws, but keep some freedom in their way of
looking or not looking at things and in their ability of
affecting these physical appearances ?*

It would look like, the laws of physics do not uniquely determine
the way things go. It would also look like the straightforward
expression of these laws seemed to fundamentally refer to the way
things are seen or measured. This reference to observers or
measurements would precisely be needed for giving things a shape
that looks like a definite appearance, and also to operate the
"choices" of how things turned out to go among their diverse
possible behaviors.

But it would also look like, this reference to observers and the
related "choices" of how thing go, expressed in the theory, only
came in mysterious circumstances that the theory itself cannot
describe, since no physical law can describe consciousness.

The theory would seem to describe things as if the alternative
possibilities actually keep coexisting as long as the theory is
strictly followed without arbitrarily involving this mysterious
reference to observers (which describes "what happens when nobody
is looking"), since things cannot "know by themselves" whether
they are looked at or not, whether they are chosen or not, thus
won't restrict their possibilities just because of this.

It would look like, if we tried to take these laws very seriously
for what they exactly say while dismissing that mysterious role of
observers by lack of a "reasonable way" to physically describe it,
the theoretical consequences would look just the same as the
particular case of the above when nobody had a look on an outcome
yet: it would look like a persisting coexistence of the many
possibilities, between which no actual choice ever came to provide
to any of the possibilities any more reality than others.

When an undetermined outcome became physically observable (i.e.
the possible result physically behaves like an objective fact
which can no more be changed by observation, as the theory must be
able to allow for that kind of behavior when several observers are
present) but still remains unobserved, no physical effect can
distinguish anymore whether or not it might be already observed
and thus made definite by some spy; therefore, the only thing that
would seem formally clear from the theory in this physical
circumstance, is that the "choice" between possibilities would
have to be fixed no later than when a known conscious observer is
looking at the result; but the question of how much earlier would
remain unclear.

For physicists looking for a way to complete the picture of
effective laws by further hidden physical laws aiming to specify
the operation of these "choices", it would look as if any try to
settle these choices as predetermined
by the hidden laws would run into many problems, while any
idea of letting these choices be only settled a bit later, would
embarrassingly surprise itself by its mysterious
need of expecting this to successfully fix the choice no later
than when someone looks at it (as if it ever mattered),
which might technically fail to happen since the physical borders
of observability remain unclear.

In short : the laws of physics in such a world would look pretty
much like those of quantum mechanics.

Welcome home. ;-)

- There are (only)
**2 fundamental substances**(kinds of realities) :**the mathematical, and the conscious**. Consciousness can explore mathematics, but mathematics cannot describe consciousness. This irreducibility of consciousness can be formulated as:*Artificial Intelligence cannot pass the Turing test*. (It could seem to pass the test when it was too short and not serious enough; an equivalent formula avoiding this risk, is :*There will be no technological singularity*- even if a leap forward would be possible if only a few people cared). While mathematics is analytic (parts of a system can be considered separately from other parts), consciousness is fundamentally synthetic (possible distinctions between its parts or aspects are mere approximations, never absolute separations). A few more hints are described below.

- By intrinsic necessity (independently of any physics)
consciousness is subject to a
**time order**, that is the**relation of relative existence**between conscious events : past events exists, but future events "do not yet exist" (they are not determined yet) even though some yet undetermined future will have to exist, that will preserve the current reality of our past and present events, into its "memory" of the past. (The mathematical reality itself is subject to a very similar time order. This mathematical time plays no role in physics, but the mathematical evidence for the time order of mathematical existence, supports by analogy our natural intuition of a time order between existences of conscious events, as a fundamental property of existence). - As far as the explanation of our experience is concerned, the
conscious reality displays a "spatial structure" (a practical
division, not a fundamental one) orthogonal to its time
structure) : it is split as a
**multitude of individual minds, that coexist in a common Matrix**. The Matrix is the "hidden" aspect of consciousness, that is the (non-mathematical) structure connecting all individual minds, defining their co-existence and communication (all minds existing "somewhere deeply inside" each other), and their relation with the mathematical world. It is not absolutely "something else" than minds, but it is their necessary extension beyond their clearly explicit (individual) appearances. Metaphorically, the Matrix contains the individual minds like a physical space contains individual physical objects. A mind cannot be absolutely conceived separately from the whole Matrix, just like a physical object cannot be conceived without a spatial extension in some space also containing other objects.

- To create the physical universe, Consciousness first
**chose a mathematical theory**defining the shape of the mathematical landscape that will be explored: this "theory of everything" of physics, is that of a Hilbert space with more mathematical structures (or some similar theory behaving as such in practice). Just like mathematics in general is the science of all possible (mathematical) worlds, which equally exist in a mathematical sense, this chosen**Hilbert space is the "landscape of all possible physical worlds"**, all structured by the same physical laws with the same values of physical constants. At first, all these worlds still only have the same mere mathematical existence they had, independently of any conscious event: this quality of mathematical existence, is uniformly possessed by all possibilities, with no sense of any comparison between them (of amplitude, number, or frequency of occurrences).

- Progressively along conscious time, specific possible worlds
inside this landscape may receive
**physical existence**, that is, the occurrence of being "physically perceived" by consciousness.**The physical universe is the trajectory of this exploration of the Hilbert space by consciousness**: at every conscious time, the physical state (usually nicknamed "wavefunction", in fact the density operator), is the projected mathematical image in the Hilbert space, operated by the Matrix, of the heritage (universal conscious memory) of all past (conscious events of) physical perceptions. By this computation, the Matrix obliges all physical perceptions to stay mathematically "coherent" with each other inside the Hilbert space. The "wavefunction collapse" is the modification of the physical state due to the addition of new physical perceptions to the heritage of past perceptions, from which the physical state is computed.

- The deterministic unitary evolution of quantum theory is the "purely mathematical" layer of physics (4.), which does not deal with the concept of reality as we normally understand it. It ignores any concept of a difference between a universe that "physically exists" and one that doesn't (but that only "mathematically exists"). It includes a mathematical representation of time as a dimension among others (and something more subtle in quantum gravity), which does not have the living essence of time, but is symmetric with respect to the exchange between past and future. All the ongoing research in particle physics and quantum gravity is dedicated to refining the details of this fundamental layer.
- The wavefunction collapse (5.), basic step of the exploration
(continuous creation) of the physical universe, is a
non-physical process, that belongs to the "metaphysical" layer,
providing the reality of a (chosen) specific version of universe
(among other possibilities from the many-worlds). It does not
have to be "defined" or "located" inside the mathematical laws
of physics. The asymmetry of conscious time (that only past
perceptions exists, together with a "complete
specification" of the state of the universe at the Big Bang),
gives the time orientation of thermodynamics : the state at a
time is given from the past, ignoring the future. This orients
entropy creation, thus also decoherence, which provides a
(time-oriented) physical basis for the classical probabilities,
that the chances of result of "wavefunction collapse" are
supposed to follow. The conceptual difficulty of "what is
randomness" and the mystery of having laws of physics predicting
random effects coming "from nowhere" (without any physically
definable cause nor localizable source of the specific result),
is explained by the metaphysical (conscious) source of this
"random" choice.

Four things remained to be discussed (and the possible relations between them) :

- The relation between measurement (conscious perception) and decoherence
- The EPR paradox
- Free will and does it contradict Randomness
- The Participatory Anthropic Principle

Therefore, for free will to act on matter by means of wavefunction collapse, two ideas of method may be considered:

- Either quantum states are observed and modified before decoherence
- Or they are perceived after decoherence but the result is chosen with a deviation from the quantum probability law.

Henry Stapp proposed the first option : conceiving free will in
the form of measurements done on a quantum system, affecting the
state of this system in the way expressed by the projection
postulate (which is how the effects of measurement are usually
described in courses of quantum physics). He considered this to be
a means to exert free will even if the perceived results follow
the quantum probabilities, because the projection postulate sends
the state to some projected images (depending on result), whose
barycenter, weighted by quantum probabilities, differs from the
initial state. More precisely, he considered this process as
usable in the form of the quantum Zeno effect, to produce a wanted
effect on a physical state.

This can only work if the projection postulate is applied as
describing the effect of a non-physical measurement process on an
elementary quantum system, in the absence of physical interactions
with the environment and their decoherence process. Because if the
quantum Zeno effect came as a consequence of frequent physical
measurements (physical interactions) which then decohere and are
observed in conformity with quantum probability laws, then
non-material free would not have a place to intervene in this
process.

- The values of physical quantities do not fit : decoherence
processes in the brain are much too fast to let conscious
perceptions intervene first.

An article on the importance of quantum decoherence in brain processes

"We find that the decoherence time scales (∼10^{-13}–10^{-20}s) are typically much shorter than the relevant dynamical time scales (∼10^{-3}–10^{-1}s), both for regular neuron firing and for kinklike polarization excitations in microtubules." - Same problem with conservation laws as Spontaneous collapse theories.
- The projection postulate only describes the way things can go
when a system is measured by means of a physical interaction
with a measuring device, whose measurement result decoheres
before being consciously perceived. There is no a priori reason
to consider this postulate applicable to the effect of a
non-physical perception of an elementary quantum state, in the
absence of a physical measurement process. Moreover, the
projection postulate itself is not even the most frequently
adequate description of physical measurement processes
themselves as they are done in practice (as explained by David
Wallace). Thus, taking it as a source of inspiration to
describe how free will can act, such as by the idea of the
quantum Zeno effect, seems quite dubious.

- The "wavefunction collapse" as conceived in the above metaphysical principles, appears much better mathematically represented as a selection of a possible world after "physical measurement" (decoherence after interaction with a measuring device), than as an application of the projection postulate for a non-physical measurement (i.e. a measurement that would happen "spontaneously" without physical interaction).

There are 2 metaphysical principles motivating the interpretation by selection of worlds after decoherence rather than the projection postulate.

- The fuzzy, synthetic, tasty nature of conscious perceptions, better fits with the characters of decoherence and its "preferred basis" problem, than with those of elementary measurement of elementary systems, that the projection postulate involves.
- The idea that new perceptions must contribute to the physical state by adding themselves to the heritage of past perceptions from which the state is calculated, but cannot delete any part of this heritage. The logical deduction from this principle (which can be seen as the metaphysical side of the physical conservation laws) can be explained in the following ways :
- In the absence of decoherence at each perception, it would
not be clear how the different perceptions would "add up" in
the Hilbert space: the result would be some kind of barycenter
of the different perceptions, but with which weights ? All
perceptions are equally real, and it would not make sense to
compare their weights, saying which pack of perceptions has
"more reality" than which other pack of perceptions, making a
sort of competition between them that would let several
realities somehow cancel each other out. Defining the state at
a time as an average (barycenter) or previous perceptions
(such as : spin up + spin right = spin up-right), would allow
for a new perception compatible with this average (such as
spin down) but eventually incompatible with one of the
components it is made of. Only the decoherence framework can
make sense of this "addition" letting all perceptions be
completely real, independently of any comparison of weights
between them, and ensure
*all*perceptions to be coherent together while summing up the requirement from past perceptions simply as a state in the Hilbert space, as normally defined. - By decoherence, a measurement result is no more carried by just one elementary object, but it has many copies, that cannot be all tracked down. Even when some new perceptions will "officially destroy into entropy" some copies of the information on some physical systems in order to effectively carry the new information, it cannot be said to erase the previous observation because some unaffected copies keep existing elsewhere that will not be subjects of this official destruction into entropy, even if they finally all turn into entropy in a passive, practical sense (of never happening to be measured anymore).

In particular, the projection postulate would not fit if applied to the case of a purely non-physical measurement, as it would enter in conflict with the principle of preservation of the past memory : the new perception negates the part of the density operator that is purely orthogonal to it (that belong to alternative worlds which are incompatible with this one), however the non-diagonal elements of the density operator between the image space (the new world) and its orthogonal, should (metaphysically) "survive" but the projection postulate appears to annihilate them.Now, if we admit on such metaphysical grounds that the physical effects of perception have to fit inside the decoherence framework, thus excluding (?) the first hypothesis on the physical expression of free will, then we must examine the second hypothesis, and explain the following paradox : if all perceptions comply with the same framework (the choice of a world after decoherence), how to explain the discrepancy between the fact that the quantum probability laws seem to have always been strictly respected by the statistics of physical experiments, and the idea of a full expression of free will in the brain based on a wide deviation away from these probabilities.But when the perception is linked with a physical measurement, these components are not physically annihilated, but dispersed instead into the environment in the form of entropy, so that the applicability of the projection postulate is restored.

Hints for a resolution of this discrepancy will result from an analysis of the EPR paradox.

The laws of physics (in a strict sense) are relativistic invariants, but only describe the structure of the Hilbert space, not the wavefunction collapse. As the wavefunction collapse is not a physical process but a conscious (metaphysical) event, it has no necessity to be exactly bound by the structures of physical laws (such as relativistic invariance), nor any "further laws of physics" in the sense of a mathematically well-defined description at the microphysical level. Instead, a description in terms of emergent structures, and precisely the structures of decoherence, seems to fit much better the metaphysical principles.

In this context, the method followed by the Matrix to "collapse the wavefunction" is not bound by any fundamental necessity of respecting the relativistic invariance. There is no theoretical obstacle in conceiving its operations as based on some "universal time" that admits a relation of "absolute simultaneity" between conscious events, as long as this simultaneity relation remains compatible with the physical relation of causal independence in space-time.

Such a simultaneity structure, if it is needed, still has a major advantage over the simultaneity structure needed in some other interpretations of quantum physics (such as hidden variables and some Spontaneous collapse interpretations), because it is a non-physical structure :

- It does not suffer from the impossibility to specify a mathematical determination of how this simultaneity relation itself evolves in space-time in the face of the space-time curvature described by General Relativity;
- It does not need to exist between all physical space-time points, but only needs to exist between individual minds, to order their conscious events of physical perceptions;
- We do not need to search for any new mathematical
reconstruction of Quantum Field Theory relatively to this
simultaneity structure so as to formulate new non-local physical
causality laws for collapse (or any kind of world selection)
there.

Now let us consider this latter hypothesis and see where it goes.

Consider an EPR experiment where both measurement events A and B (conscious perceptions) are separated by a space-like interval, so that the question of which one happens first, is not a relativistic invariant.

In one viewpoint, A happens first, so that it "chooses" its result, only bound by the constraint of compatibility with the quantum probability law as it comes in the absence of the measurement B. Then B happens, but facing a different context: its "choice" is bound by the fact that A happened first, which modified the quantum probability that B faces, in comparison with the case if A did not happen. Moreover, in the extreme case that both measurements are done along the exact same axis, B does not have anymore choice at all.

In the other viewpoint, the time order between A and B is reversed, so that the same story can be said, but exchanging the roles of A and B.

Now the question is : can we reconcile both viewpoints, by adding up their necessities, and telling the story in a way that keeps the symmetry between A and B ?

Note that if A comes first but both measures happened to be made in the same direction, then B's result cannot be chosen at all, but is determined by A's result. But this should remain true if reinterpreted saying that B comes first. In this case the question whether B has any choice or not, cannot depend anymore on whether the directions of measures are the same or not, since A's direction cannot be claimed to have been chosen yet. Therefore we should conclude that, anyway B's result is not chosen at all, disregarding what A does.

Note that this conclusion simply coincides with the way things naturally appear : when we are observing something, we do not have the feeling that we are making any choice on the result of our observation. It all looks like, this result is given to us from the outside. However, it cannot come from a physical outside, since... there is no such a thing as a physical reality, and the measurement result did not really exist before it was perceived.

Instead, what exists outside the individual minds, and that provides the perception results, is the Matrix. And the Matrix provides to each individual mind his perception results, every time immediately in reaction to this mind being about to have that perception (thus after decoherence). And in order for this behavior of the Matrix to keep a relativistic invariance, it has to strictly operate, in its way of "choosing" the data, a randomness in conformity with the quantum probability laws, in a non-local, holistic manner.

Now what if experiments do not confirm this, but on the contrary, display an effect deviating results from chance even when there are several observers (and with even higher amplitude) ? Maybe, because this cannot anyway constitute a faster-than-light communication, since the different observers are quite close to each other and they have a perception delay of, maybe 0.1s, that is much slower than the time needed by the light to cross the distance between them; so that it is not "who observes first depends on the space-time coordinates system" but "all observers are equally first observers anyway".

From this, follows an idea of answer about how the situation inside the brain differs, so as to open the possibility for the mind to exert free will inside the brain by deviating the perception results from a randomness complying with quantum probabilities : that, when a quantum random process occurs inside a brain, there is only one mind that will clearly be the first observer of that process, with no ambiguity from a relativistic invariant perspective.

The interest of this idea, is that it might be experimentally tested, by setting a quantum randomness generator whose output would be carefully confined for having a clearly well-defined first observer, and checking if that observer's will can influence the output of this generator. The most obvious way would involve a device like Google Glass to directly project such random light signals onto the retina. However I am not sure if such confinement methods would suffice. If it fails, it might be because of insufficient confinement. Maybe, a effective success would require some way of inserting a random generator directly into the brain. Such an experiment might be tried on animals too, though it would be much harder to explain to them to "try to influence the result by will"...

In the article *Is
Quantum Indeterminism Relevant to Free Will?* by
Michael Esfeld (2000)

it is stated that the idea of free will is physically unacceptable
as it would be a violation of one of the laws of physics : Born's
probability rule.

It is compared to some ancient speculations (by Descartes) on how
a non-physical mind would act on matter by a "non-physical force"
that would violate the conservation laws of classical mechanics:

"Indeterminism in physics in the described sense opens up the possibility of an interactionism which does not have to assume a force over and above those force that are acknowledged in physics. It thereby reduces the ontological burden of interactionism.

(...) instead of having to endorse an additional force for metaphysical reasons, we have to endorse a change to the probabilities that a physical theory indicates for metaphysical reasons.

Within the framework of the positions considered in this paper, the conclusion is as follows: taking everything into account and given the current state of the art, quantum physics does not reduce the price which one has to pay for interactionism."

Visibly, he contradicts himself on the question whether the
"burden" or "price" is reduced or not by taking quantum randomness
as the place of operation of free will. In his mind, the diverse
"laws of physics" seem to be assumed as being all at "the same
level" of necessity.

These are quite naive and far from any kind of well-assessed
comparisons "given the current state of the art", I would say. By
the way, whose "state of the art" is he referring to ? Probably,
the one of science philosophers
trained with their usual bullshit kind of "reasoning", who pretend
to discuss science without having any decent understanding of the
needed concepts and theories.

Actually, Born's rule is very far from having a status of
"physical law" with a necessity for things to obey it, that can
stand any comparison of strength with the the conservation laws of
mechanics. These conservation laws (of energy, momentum...) are
not mere "postulates" like arbitrary assumptions, axioms or
speculations, but come as **theorems** in either framework of
General Relativity and QM. Thus, there is absolutely no way, even
for any God, to violate them, as this would contradict a
mathematical theorem. It is absolutely impossible, logically
unconceivable (the only "conceivable" process that would look like
this would be a transformation of ordinary matter into dark
matter, but that is still so unlikely....).

- This "rule" only qualifies what happens during "wavefunction collapse", which operates in mysterious circumstances : there is no such a thing as a verified law of physics that describes how this collapse "happens", and it is a matter of interpretation whether it happens at all, when and how.
- There is no such a thing as a possible exact mathematical
definition of what it means for phenomena to be "typical", i.e.
to "follow a given probability law", as opposed to "deviate from
this law". Because, first, laws of physics are local, so that
only a finite number of observations can be analyzed at at time.
Every possibility getting a "nonzero probability" by some
probability law, remains possible according to this law (as, if
it wasn't possible then its probability for this law would be 0
by definition !), so that the occurrence of this possibility
cannot be said to contradict the law. Therefore, no possible
(nonzero probability) outcome can be said to contradict the law
if it happens.

- Does it make sense to consider as "violation" of a probability
law, the occurrence of very unlikely possibilities (with
probabilities close to 0) ? Actually, it is not. Indeed,
consider the concept of entropy : it is the measure of the
average expectable unlikeliness of the specific exact state of a
physical system occurring at a given time. Usual values of
entropy of macroscopic systems (i.e. typical numbers of possible
elementary states across which actual states typically "choose")
are VERY big compared to their absolute unit (the Boltzmann
constant). So, it is
**very likely**for a physical system to be in a**very unlikely**specific state. - Among all possibilities that are similarly very unlikely as each other but globally likely when put together, any claim that some of these are "more unlikely than others" is relative to an arbitrary choice of a "typicality criterion" that would distinguish a specific subset of possibilities as "less typical than others" in the sense that "this is a small set for the probability law" : the "total probability for the outcome to be unlikely according to this criterion", defined as the sum of probabilities on this set, is close to zero. However, there is no such a thing as a fundamental law of physics which naturally comes to specify how this set, to be taken as the definition of "unlikeliness", should be chosen. Ultimately, the choice of an "unlikeliness" concept, can only come as a matter of taste. It is a purely subjective, psychological concept instead a physical one.
- So, if my free will comes to choose the outcome of a "random process", while the physical "probability law" would give it only a small chance of happening in this way, then we might say that the physical probability law only gives a small chance for my will to be satisfied. In this sense, the satisfaction of my will by the outcome is an "untypical event". However, this untypicality concept is only defined in relation to the subjective preference of my thoughts and will, which is of an unphysical nature. The definition of which outcome I happen to prefer, is only a matter of taste ! This preference or untypicality concept cannot be mathematically formalized to be used in the expression of any self-contained mathematical law of physics. We cannot mathematically define any precise concept of "typicality" to be used in any additional "physical typicality law", from the viewpoint of which the satisfaction of my will by the outcome of "random events" can be said to "break that physical typicality law" by its untypicality.
- Of course, what did you imagine ? This is no news to say that, on a deep level, no conceivable "physical law" defined by any kind of mathematical theory can ever succeed to give to the concept of "probability" any "real sense" that fits with its intended metaphysical idea that "only one possibility will become real but the choice is not determined yet", but that it requires an appeal to a metaphysical source of randomness with a metaphysical interpretation of probability instead. Otherwise, supporters of the different interpretations would not spend that time criticizing each other's troubles in properly explaining the sense of probabilities and justifying the Born rule, as an excuse for their own inability to do so themselves.
- Assume for a moment that the presence of immaterial conscious
beings with their mathematically indescribable free will able to
act on matter, was a metaphysical precondition for some material
universe to possibly exist. Assume also the universe still needs
some mathematical structures to give it a shape, but that would
have to be compatible with both kinds of circumstances:

- Providing a plurality a possibilities available for the intervention of a choice by a non-physical free will ;
- For the outcomes of those physical processes that the mathematical structure would happen to leave undetermined (as it must for the provision of the previous case), but that do not happen to be influenced by anybody's preference, some kind of trends still have to be given ;
- In conclusion, as the theory only postulates randomness with no explanation of its source, it is pointless to theoretically refer to the fact it gives a "probability law" as if such a law could really make rigorous sense ; the only meaningful argument is a matter of checking the statistics of observations and how they fit the "law". And the fact is that significant deviations from the physical "probability law" by the influence of free will have been observed (see references below).

This objection appears in diverse articles on the subject : "The
kinds of indeterminacies discoverable at the quantum level may not
correspond in any useful way to our ordinary idea of mental
causes."

The answer is that quantum randomness is much more pervasive in
reality than many people naively imagine when thinking that many
phenomena, such as classical chaos and the randomness of
statistical mechanics, can be understood without reference to
quantum physics. I mean that while, admittedly, the place of
not-yet-decohered forms of quantum superposition, that require the
quantum mechanical concepts to be understood, seems limited to
molecular scales irrelevant for consciousness, quantum randomness
is anyway the real source of a large flow of effectively random
data (classically probabilistic superpositions produced by
decoherence), where free will has a wide margin for possible
intervention. More comments on this fact in the text on Bohmian mechanics.

One explanation I said above : it requires to clearly specify its
principles and their exact connections with physics, which was not
properly done by previous supporters.

The other explanation : since consciousness is not physical, it
cannot be "explicitly found" when strictly focusing the study on
properties the physical world.

If consciousness is needed to collapse the wavefunction, did the
Universe exist, either precisely or in potential (in a large
superposition of states) until some intelligent life appeared on
Earth to observe it and do the collapse ?

I was surprised to see that some of the physicists who support the mind makes collapse interpretation, actually also support that idea. What is strange here, is that for this conclusion to be "deduced" from its explicit premise, it needs to assume another premise that, I would say, contradicts the first premise, so I wonder why it is so often implicitly taken for granted without justification : the materialistic principle that (the presence of) consciousness is produced by the structure of biological systems (and more precisely some brains), so that consciousness cannot observe the universe from outside these systems, and thus could not be present in the Universe before they appeared in the course of evolution.

I find it quite a strange assumption. I would just dismiss it as
ridiculous and not deserving attention, together with its
resulting Participatory Anthropic Principle itself, if it did not
seem to have that number of supporters. But since it appears to be
part of the landscape of opinions, I will develop here the
arguments.

One argument against it, is the data of parapsychology, especially NDE and OBE: many of the near-death and out-of-body experiencers first have (mainly visual) perceptions of our physical reality from outside their bodies before eventually exploring other realms. Some other testimonies such as haunted houses or the Faustina diary, suggest in other ways the actual presence of unincarned spirits as well. So, if some minds can be present outside bodies to observe us now, what could be the problem in the idea that such minds (just less anthropomorphic) could be present to observe the Earth and other parts of the Universe before "intelligent" animals appeared during evolution ? I understand it would may have been "less interesting" for more rudimentary biological systems, but...

For example some NDE testimonies here and there tell about afterlife of animals (see the whole debate for which I initially found these links).

Now what about earlier times, when there were only unicellular organisms, or even before, were there any souls on Earth or in other "lifeless" parts of the Universe ? It could have been very boring for these minds to wander here trying to play with mere unicellular organisms, or no biological system at all. Still some sould could have been here to stare at the landscape, the sky or such (and others spending time in more interesting realms as suggested by NDEs).

But our initial question, in fact, can be split into 2 questions to be discussed separately:

Can we locally consider a total absence of souls on Earth for a very long time, such as the first 2 or 3 billion years of its history, letting it split into very many parallel worlds, until some soul just suddenly came to select and give existence to one of these many worlds, precisely because of some "interesting" organisms it contains, therefore creating the past evolution retrospectively ?

I don't see this as reasonable, and here is why:

To find out whether some conditions on a planet and the organisms
present on a planet are suitable for hosting consciousness, cannot
be done at first site. Because the property for an organism to be
a comfortable host for consciousness and that can work in the long
term in the face of all kinds of events, is a complex problem. It
cannot be found without doing some experiments with it. So,
imagine that you let a planet without any mind for millions of
years, it divides itself into an extremely wide diversity of
parallel worlds, then, in mysterious ways you manage to browse
through this unthinkable diversity and feel that one of the
possibilities may be nice. They you do it a try. You enter some
organisms there and bring your friends with you. But finally you
find yourself very uncomfortable. Will you leave ? Or, you disturb
the behavior of your body so badly that it dies. Or, you play it
so well with your friends, that the host specie becomes too
strong, disrupts the ecological equilibrium of the planet (driving
its predators and then its food to extinction) and finally
disappears due to this disruption. What can you do then ? You have
collapsed the wavefunction, it is too late to un-collapse it now.
The planet is corrupt and not suitable for conscious life anymore.

I would rather guess that consciousness was always there from the beginning of evolution, first in disembodied forms, then progressively playing with organisms in more and more committed and elaborate manners. Then "completely embodied" but still intelligent configurations progressively came to dominate, due to their selective advantage (as they "force the mind to cooperate" by their intelligence for the survival of the body).

Reference : The
Watchmaker by James Huber.

See remarks about the role of the big bang in the context of the many-worlds interpretation.

See my site against spirituality and religion, with summary of my rationalist position ; how I separate metaphysical and religious issues; and my comments on the unfortunate practical division between science and the sense of life (or "fundamentally interesting issues" for the public) here and there.

By other authors :

Debunking
the Law of Attraction and "Thoughts Create Reality" Religion

New
Thought : Problems

The debate on quantum idealism (other possible name for the mind makes collapse interpretation)

Many references on consciousness and quantum physics moved to a separate page

Main page of arguments on quantum physics interpretations

Many Worlds(I also have a page on metaphysics, strongly connected with this issue of interpreting quantum physics, though it may be not so clean, I will consider to revise it later.)

The de Broglie-Bohm interpretation