New Post: "Does quantum mechanics speak to Catholic Teaching III: the Measurement Problem"

Hello all and a Happy New Year to you.  A new post "Does quantum mechanics speak to Catholic Teaching III: the Measurement Problem"   I discuss the philosophical and thelogical implications of this and other aspects of quantum mechanics.

New Post: "Does Quantum Mechanics Speak to Catholic Teaching?"

Hello all.  A new post on the Magis Center for Faith and Reason website: "Does quantum mechanics speak to Catholic teachin? II: Quantum Mysteries Intersect Theology"    I discuss how the superposition principle might yield an example, an analog for the Holy Trinity, explain with a simple example what quantum entanglement involves and how quantum mystery supports Catholic teaching.  Enjoy!  Comment!

Free Will and God's Providence: Part IV--The Many Worlds/Many Minds of Quantum Mechanics

"Do not keep saying to yourself, if you can possibly avoid it, 'But how can it be like that?' [referring to quantum mechanics]because you will get 'down the drain', into a blind alley from which nobody has escaped. Nobody knows how it can be like that.” Richard Feynmann 

"If we look at the way the universe behaves, quantum mechanics gives us fundamental, unavoidable indeterminacy, so that alternative histories of the universe can be assigned probability."  Murray Gell-Mann

The video to the right (from YouTube) is from the introduction to the TV show Quantum Leap , which had the hero jump from one possible world to another, saving people in dire situations and altering history.

INTRODUCTION

In the third post of this series on Free Will  my final comment was

"It seem to me that if God knows what we will do--even if he does not determine that we do it--we are not totally free in our moral choices.    There need to be options, different possibilities for what we can do, in order that freedom of choice--free will--be exercised... In the fourth post of this series I'll explore what quantum theory might offer to give this freedom."

That part of quantum theory that intersects with Molinism (God's Middle Knowledge) is Everett's Relative State Theory, more commonly known at the quantum Many Worlds Interpretation (MWI) or Many Minds Interpretation (MMI).    I'll give a bare bones summary of the relevant quantum mechanics (and references) and then try to show how the MWI can be joined to Middle Knowledge to give a frame for both God's omniscience and man's Free Will.    Quantum mechanics references are also given in a previous post.    Dear Reader: if all this quantum mechanics jazz makes you queasy (as it does my wife), you can skip to the end of this post to get my take on the connection with Middle Knowledge and Free Will.

THE SUPERPOSITION PRINCIPLE IN QM AND THE MEASUREMENT PROBLEM.

Superposition in quantum mechanics is best illustrated by  the double slit experiment.   In classical optics, if you pass a light ray through two narrow slits you'll see an interference pattern as illustrated in the figure below.

Young's Double Slit Experiment, abyss.uoregon.edu

The light beam at the top is split and passes through the two slits in the middle.    Each of the light rays passing through a slit is a wave, which has positive and negative amplitudes.   When a positive part of the wavefront from the left-hand slit meets a positive part from the wavefront from the right-hand slit, they reinforce, to give a bigger wavefront.    When a positive part of the wavefront from the left-hand slit meets a negative part from the right-hand slit, they cancel to give a smaller or null wavefront.   This phenomenon is interference.  The result of the interference is shown on the screen (bottom green band) where the reinforced waves (adding) give intense bands (white) and the canceled waves (subtracting) give dark bands.

One of the puzzling features of quantum mechanics is that particles (electrons, protons, etc.) can behave like waves (as in the light ray above) and waves  can behave like particles (e.g. light behave as photons) according to the kind of experiment used to study

them. Thus, in the figure below, we see particles showing interference patterns, as if they were waves.    (If the screen is removed and collimating tubes added as at the bottom of the figure--even after the particles pass through the two slits, as in the delayed choice experiment )--then there is particle-like behavior;   red and green particles behave as if they passed through the slit without interference effects--no wave-like behavior.

This behavior is represented in quantum mechanics as a superposition of states.    We use the notation " | state>" to indicate a system is in a given state, or for our example of the double slit experiment:
| state> = | left slit> + | right slit>
which is to say that a particle going through the slits is going through BOTH the left and the right slits--it is a superposition, as would be the light wave.       Now if we put a measuring device near the screen with two slits to detect which slit the particle might have gone through (or use the detecting screen removal and collimators), then we get in the common interpretation of QM,
| state> = | left slit> + | right slit> --(measurement)-->| state> = | left slit>  or
  | state> =  | right slit>,
That is to say, the measurement process has "collapsed" the state function from a superposition to either a particle having gone either through the left slit or through the right slit, but not both simultaneously.   (Note: what I have termed "state function" is often termed "wave function", although in many instances there is no wave-like behavior associated with it.)

CONSCIOUSNESS AS A MECHANISM FOR COLLAPSE

Measurement interaction with the particle before it reached the screen (in a superposed state)  has effected the collapse, but the mechanism by which this collapse occurs is mysterious,   It is represented by so-called projection operators, but these are not implied by or contained in the fundamental equation of quantum mechanics, the Schrodinger equation.   So the collapse of a superposed state by the appropriate measurement poses a problem of interpretation.

In the early days of quantum mechanics two great theorists, John von Neumann and Ernst Wigner, gave the following interpretation:  since an observer is required for a measurement, and since the final stage of an observed measurement is the belief in the observer's mind of the result of the measurement, one might conclude that consciousness is the means by which the collapse is effected.    This interpretation has been taken up with enthusiasm by followers of Eastern mysticism who do not understand quantum mechanics (see What the Bleep for an egregious example) and by some physicists and philosphers, although it is rejected by many physicists for the reasons given below.

If consciousness is the mechanism for collapse of a superposed state,  how does one explain what happens if no conscious observer is present?    For example, who would the observer be for the universe as a whole?  (One answer might be God--see  Quantum Divine Action via God, the Berkeleyan Observer, but that would clearly not satisfy many physicists.)    What happened in the early universe when there were no conscious observers?   The famed American physicist John Wheeler would answer in his Participatory Universe that the past is created by our observation of it.  

A more important objection was raised by Hugh Everett:  if you consider nested observers, for example, conscious A observes state | S>;  conscious B observes (conscious A observing state | S>), you can deduce contradictions if you try to employ  consciousness inducing collapse.    Such contradictions led Everett to his revolutionary  Relative State Theory (see below).

 EVERETT'S RELATIVE STATE THEORY:A STATE FUNCTION FOR THE UNIVERSE.

In 1957 Hugh Everett, then a grad student at Princeton under John Wheeler, produced as his Ph.D. thesis a revolutionary interpretation of quantum mechanics he called "Relative State Theory"and in a later publication (1973) "A Theory of the Universal Wave Function".    As Jeffrey Barrett puts it

"[Everett] wants to drop collapse dynamics from the standard von Neumann-Dirac formulation of quantum mechanics, then deduce the empirical predictions of the standard theory as subjective appearances of observers who are themselves treated within pure wave mechanics as perfectly ordinary physical systems.  The problem, however, is that is unclear precisely how Everett intended to account for the determinate records and experiences of observers." J.A. Barrett, The Quantum Mechanics of Minds and Worlds 

Everett's idea was to partition the wave-function (state-function) for the Universe into parts for observers and a part (the relative state) for the rest.   A given measurement result would be recorded by a given observer, another result for the same physical quantity by another observer.   The explanatory gap as to how exactly this would be done (pointed out in the above quote) has led to many theories building on Everett's, theories of "Many Worlds/Many Minds".

MANY WORLDS/MANY MINDS THEORIES OF QUANTUM MECHANICS

In 1970 Bryce DeWitt gave the first of many interpretations of Relative State Theory, a "Many Worlds",  in his Physics Today article.    DeWitt proposed that at each measurement all possible results occurred, such that worlds split.   Thus with the double slit experiment described above, two worlds would result:  one in which the particle had gone through the left-hand slit and one in which the particle had gone through the right-hand one.   Although this became a standard staple for science-fiction, this interpretation has problems, to name just two:

1.  How are quantum mechanical probabilistic interpretations of measurement applied?
2.  What happens to the identity of the observer--is he in the world with left-hand slit or right-hand?

Other interpretations followed.   (I'm not going to do more than list the most important of these with a brief explanation and online references (where available);  for fuller descriptions, see Jeffrey Barrett's book,  The Quantum Mechanics of Minds and Worlds.)

• Many Worlds:  measurement splits the world into alternatives, one for each component state in the superposition
• Many Histories: the linked reference gives Barrett's evaluation of Gell-Mann/Hartle's "Many Histories" approach to Relative State Theory, in which decoherence, interaction of a system with its environment, removes the superposition of component states.
• Many Minds: instead of measurement splitting the world, each observer has an infinity of minds, whose distribution is probabilistic and evolves with time, but which are not superposed--a measurement is registered in one of these minds.   This approach has been advocated by Albert and Loewer, Lockwood and others.

In addition to the interpretations above, Barrett describes the Bell's (of Bell's Theorem) Everett(?) (sic) Theory,  Relative Facts Theory and Many Threads Theory in his book.

A common objection to all the above theories is that they are "ontologically extravagant"--they propose too much of reality.   But since God is infinite, is that a valid objection?     All the interpretations are supposed to fill  the following two requirements, among others:

• They satisfy the same empirical requirements as standard quantum theory (give the same predictions).
• They show how only one of the possible measurements made on a superposed state has been recorded by an observer.

None of the theories, according to Barrett, are totally satisfactory from a philosophical point of view.

Nevertheless, I will suggest below how one or another of the above might mesh with a Molinist point of view to reconcile God's omniscience and man's Free Will.

MESHING MANY WORLDS/MANY MINDS WITH MOLINISM

Now, finally we come to the point of this post and I will be brief.   Let's suppose that a science-fiction perspective for personal worlds exists, a multitude of possible worlds  in which there is one where I/my ego/my soul exists.    When I make a moral or ethical decision there will  be, not a splitting into the two different worlds that would ensue from different decisions, but a possibility for me--my ego, my soul--to go into one or another of those worlds.     In this view, God knows of all these possible worlds (the Molinist worlds of God's Middle Knowledge) that might ensue from my moral decisions.    Thus God's omniscience and the availability of choices required for truly free, Free Will, are compatible.

REFERENCES (other than links given in the post)

Quantum Enigma: Physics Encounters Consciousness, Bruce Rosenblum and Fred Kuttner--a clear, non-mathematical introduction to quantum physics with an emphasis on the many mysteries.

The Quantum Mechanics of Minds and Worlds, Jeffrey Barrett--a comprehensive review of the various interpretations of Barrett's Relative State Theory, deep philosophically but not mathematically.

The Philosophy, Theology and Science of Molinism, Max Andrews--I have not read this book (it has not been published at the time of writing this post) but it seems that it would be relevant and interesting

Do Quantum Entities Have Free Will? (And Do We?); Or, "Does it Matter if God Plays Dice?"

"Of course I believe in free will. I have no choice."  The Salon Interview, 1987, Isaac Balshevis Singer,   "There is no evidence for determinism." Princeton Lectures, John H. Conway "Philosophy is too important to be left to philosophers" Unification beyond the Core , Frank Wilczek (also attributed to John Wheeler) "Does it even matter if God plays dice?"  Rachel Thomas' Plus-math Interview of John Conway "...dearly beloved...be not disturbed by the obscurity of this question; I counsel you first to thank God for such things as you do understand; but for all which is beyond the reach of your mind, pray for understanding from the Lord, observing at the same time peace and love among yourselves... "On Free Will and Grace , St. Augustine of Hippo

The Proof of the Kochen-Specker Theorem
(from plus-maths discussion, by Rachel Thomas)

In one of the later Foundation novels, Isaac Asimov envisages a world, Gaia, in which a super conscious mind pervades the world, from the smallest virus or rock to the humans (and robots) in it.   In such a world it would be natural that quantum entities have free will, and there would be nothing remarkable in the  Conway-Kochen Free Will Theorem :

"It asserts, roughly, that if indeed we humans have free will, then elementary particles already have their own small share of this valuable commodity. More precisely, if the experimenter can freely choose the directions in which to orient his apparatus in a certain measurement, then the particle’s response (to be pedantic – the universe’s response near the particle) is not determined by the entire previous history of the universe." The Strong Free Will Theorem, John Conway and Simon Kochen. 

I won't give an extended discussion of the proof (see the link in the caption for a very clear and detailed presentation by Rachel Thomas or the link for the quote for the rigorous mathematical proof).   Nor will I give an extended discussion of what free will might be (a topic about which philosophers have contended over the past millennia).   Halfway through writing this post, I discovered John Conway's six Princeton lectures on his Free Will Theorem online.   So really, rather than writing, I should just direct the reader to those lectures to see what the Free Will Theorem is all about.   I should also note that Conway does not claim his Free Will Theorem disproves determinism;  indeed, he says there is no way to disprove determinism, despite the fact that there is no evidence for it.

Nevertheless, I would like to use the Free Will Theorem (abbreviated as FWT) as a springboard to discuss several issues in interpreting quantum mechanics, namely how randomness and consciousness might enter into interpretations of quantum mechanics.  (Fear not, gentle reader--this will not be a "What the Bleep" presentation, or a jump into Eastern mysticism.)

From "The Spin Family"
5 sculptures by Adrian
Voss-Andreae

First, let's see how the three axioms are empirically justified by contemporary physics;  I'll phrase the axioms to make the physics clear (I hope).
1.  SPIN.   There exist particles with intrinsic angular momentum (spin) with spin quantum number, S= 1, such that components of angular momentum along a preferred axis (as defined by, say, an electric/magnetic field or a polarizer) are 1,  0,  and -1 (for angular momentum, I'm using units of hbar, where hbar = Planck's constant/(2pi)).   The three components are shown in the illustration, "The Spin Family".   The total angular momentum vector precesses about the defined direction.   The upper cone shows the component with 1; the flat disc, the component with 0; the downward pointing cone, the component with -1.     Then quantum mechanics shows that the squared components of spin in some arbitrary choice of three perpendicular directions  must be either 0,1,1;   1,0,1; or 1,1,0 .   Note that photons have S=1, which is handy, because laser experiments can be done with photons.
2.  TWIN.   It is possible to produce a pair of particles with combined total spin angular momentum  0, in what is called a "singlet" state.    Thus, if particles a and b are so produced in a singlet state, then if particle a has angular momentum component (in units of hbar)  +1 along the defined direction, particle b must have component -1; if particle a has component 0, so must particle b;  if particle a has component -1, then particle b must have component +1.   If the two particles should be separated after being created in a singlet state, their spin components will still be correlated:  if a value of 1 or 0 for the squared component is measured in a certain direction for particle a, the same value must be measured in that direction for particle b.    This "entanglement" of spin components for separated particles was used by David Bohm in his version of the EPR (Einstein-Podolsky-Rosen) paradox and entered into Bell's Theorem, to confirm (or disprove) hidden-variable theories for quantum mechanics.   Such entanglement has been verified by many experiments (done to test Bell's  Theorem) over separated distances of many miles.
3. MIN (the original third axiom was FIN, having to do with limitations of speeds of transmission because of special relativity). We'll take two investigators A and B who are separated in space. The spin system A studies is labeled a, and the spin system B studies is labeled b; a and b are separated parts of a singlet, and each has spin quantum number S=1. Then Conway/Kochen state in axiom 3 that the choices by A and B for studying direction of spin components are independent:
"Assume that the experiments performed by two investigators A and B are space-like separated. Then experimenter B can freely choose any one of the 33 particular directions w, and a’s response is independent of this choice. Similarly and independently, A can freely choose any one of the 40 triples x, y, z, and b’s response is independent of that choice."
This axiom was chosen to make the FWT stronger, and to overcome objections made to the use of the FIN axiom.

We can proceed now with a short summary of the Conway-Kochen theorem proof.   First, it rests on the Kochen-Specker theorem (KST), which itself is quite important.   KST shows that hidden-variable theories for quantum mechanics having functional relations amongst the variables, independent of measurement procedures, are not valid.    Or, as Conway puts it, "the spin chooses its value on the fly." Accordingly, the  measured value does not depend on the previous history of the world.   Conway/Kochen's proof   assumes that separated investigators (A-Alice and B-Bob) have free will in choosing the direction for measuring spin.   Then by use of the Twin, Spin and Fin axioms, and the Kochen-Specker theorem, they show, in a proof by contradiction, that there is no functional relation for spin measurements by Bob, and therefore that the spin response is independent of the previous history of its worldline, i.e. the spin system's response is "free".

What do Conway/Kochen mean by "free will"?    Both for the investigator and for particle system they mean that the choice--what is done--does not depend on previous history.   A more conventional interpretation might be that free will is the ability to freely choose amongst several options.   The term "freely" is understood, but susceptible to a number of definitions. (As with Justice Potter Stewart's definition of pornography, "I know it when I see it").   In his Princeton lectures and interviews for Rachel Thomas,  Conway is quite emphatic that this freedom is not just "randomness".    To show how randomness might enter, he sets a backgammon tournament as an example.    The tournament director casts all the throws of the dice the night before the tournament, and then calls them out sequentially as each game is played, so that there is a level playing field for each contestant.  An example more familiar to me is that of a duplicate bridge  tournament.    At each table the four hands are dealt out randomly to begin with

Duplicate Bridge: Declarer's Hand  (Wikipedia article)

and the teams rotate from table to table, so that each team has played at each table with the same dealt hands.   There is a predetermined initial lay of the cards, but the players are free to deal with the sets of hands as they will.  (Is this an example of what philosophers call "compatibilism" in free will?)   Conway strongly argues that the FWT forbids randomness as an agency, whether occurring at the event or predetermined:

"That’s why it doesn’t matter if God plays dice with the Universe, or not. Even if we allowed random numbers into the Universe, which I’ll think of as God’s dice, that’s not sufficient to explain the lack of pre-determinism in quantum physics." quoted in Rachel Thomas's article.

I have a problem understanding this assertion.    Granted that the FWT  shows that the particle response cannot be predicted by a function involving past history, how exactly does that dispense with pseudo-randomness, predetermined before the world began?    What can we learn from physics, in general, and quantum mechanics, in particular, to understand Conway's argument?

Let's consider first "random noise" in electronic devices, my old friend from nmr spectroscopy and MRI.   Such noise can be characterized by mean square amplitude and correlation times, which in turn can be related to physical parameters.  Molecular motion candidates for randomness also obey functional relationships.  I've cited these as examples that don't contradict Conroy's argument about predetermined randomness.   Can the reader cite others that might?  I can't.

Schrodinger's Cat (U. Toronto, Physics)

If we turn to quantum mechanics, the state function, which most generally can be put as a superposition of basis states ("Schrodinger's Cat"), evolves deterministically.   The randomness comes at measurement, when the state function collapses, except for that basis state which gives the measured result.    Chance/randomness for the measured result comes from the component nature of basis states, and should be distinguished from weighting in a mixture of states.  (For links to basic web material on quantum mechanics, please refer to another post of mine, Quantum divine intervention.. )  Quantum Mechanics does not include this state function collapse on measurement as part of the general theory, and thus results the so-called Measurement Problem .

Amongst the various interpretations and alternative theories which attempt to resolve the measurement problem, I'd like to focus on two:  1) the relation between the observer, consciousness and measurement in quantum mechanics;  2)  many worlds/many minds (relative state theory).   From the earliest days of quantum mechanics, the great thinkers--Von Neumann, Wigner, Schrodinger--have posited that the final step in the measurement process was observation by a mind, a consciousness, and thus the mind and quantum mechanics were entwined.   The delayed choice experiment adds weight to this belief, I believe. There are many physicists (not abashed by the popularization of this notion in quantum leap science fiction) who subscribe to the Many Worlds interpretation of quantum mechanics that at each measurement one option is made apparent and the rest branch (into alternative universes, alternative minds?).

Here finally is my take:  as with John Wheeler, I believe there is a participatory universe created by the observer, conscious minds (ours? God's? both?).  The free will of the quantum entity is our own free will.    There is an infinitude of possible universes and our ego, our consciousness traverses these as it makes choices.   If there is a universe where we measure the particle going through one slit, there is another (with other conscious minds) where it goes through both. Such a view resolves a conflict between free will and God's omniscience and omnipotence--if God knows what our future actions will be, how can our will be free?  And the answer would be a type of Molinism, God is aware of all possible counterfactuals, but they are only counterfactuals for our mind, our ego, not for God.

Quantum Divine Action via God, the Berkeleyan Observer: the Delayed Choice Experiment

Young's Double Slit Experiment, abyss.uoregon.edu

"There was a young man who said, 'God

Must think it exceedingly odd

If he finds that this tree

Continues to be

When there's no one about in the Quad.'

REPLY--

'Dear Sir:

Your astonishment's odd:

I am always about in the Quad.

And that's why the tree

Will continue to be,

Since observed by

Yours faithfully,

GOD.' "

 Msgr. Ronald Knox, commenting on Berkeleyan idealism.

"I think I can safely say that nobody understands quantum mechanics."
Richard Feynman (Nobel Prize winner for work in quantum electrodynamics), The Character of Physical Law

"I am a Quantum Engineer, but on Sundays I Have Principles."
John Stewart Bell (of The Bell's Theorem) as quoted in Quantum [un]speakables: from Bell to quantum information.

Many articles and books have been written about possible mechanisms for God's action in the world by means of a quantum mechanical agency.   I can't possibly in this brief post even summarize all of them, but references are posted below.  Rather, I'll focus on a particular experiment, the delayed choice experiment first proposed by the great American physicist, John Wheeler.  (See also Aspect's delightful lecture about his experimental test of the idea.)   Before discussing the delayed choice experiment, we should try to explain the quantum double-slit experiment on which it is based.    (I'm going to trust that the reader will hit the linked sources to get background material on quantum mechanics.)

If you pass a wave, be it light, water or particles showing their wavelike nature, through two parallel slits you'll see a diffraction pattern, alternating intense and dark bands, as depicted in the diagram above.    Waves will have a positive amplitude at a peak, and a negative amplitude at a trough, so that when two waves meet at points with both peaks, there will be a bigger peak, and at points with a peak and a trough, they will cancel to give zero, showing the interference pattern.     Now the fascinating quantum behavior of particles is that a single particle will seem to go through both slits simultaneously, interfering with itself until it hits the screen, at which point the wave collapses and the particle is at a single point.    As the linked animation shows, when many particles go through, the pattern shown on the screen is one of interference fringes, just as produced by waves.    If you try to detect through which slit a particle goes (i.e. use the camera in the animation), then you perturb the situation and the particle loses its wavelike character, so that the screen pattern becomes that for classical particles going through the two slits, a scattering without the interference fringes.

Here's Wheeler's gedanken delayed slit experiment in essence.  When does the quantum entity decide to behave like a particle or like a wave?  Is it just as it goes through the slit?  Is it after it goes through the slit?  Or???

Wheeler's Delayed Choice Experiment
 http://www.bottomlayer.com/bottom/basic_delayed_choice.htm

 What happens if you try to change the type of measurement after it has gone through  the slit?  If, instead of a screen, you use two telescopes oriented and at a distance such that they will determine which slit the particle has gone through, will you detect particle- or wave-like behavior?   Layer 4 in the diagram (4r) shows the detecting screen with a diffraction pattern (wave behavior).   Layer 5 in the diagram shows the two telescopes, collimated and oriented to detect the slit origin, and 5r, the pattern with no diffraction (particle behavior).    Wheeler proposed an astronomical version of the experiment, using gravitational lensing to provide the two different pathways/slits.   If images from two spatially separated telescopes were looked at separately (as in layer 5 in the diagram), no interference would result;  if the images from the two telescopes were combined and looked at together, phase interference would occur with a pattern of interference fringes.   There's an interesting and significant corollary to this experiment.    The light source--some distantgalaxy--is millions or billions of years in the past--but you're affecting it by the present day measurement.   From which corollary Wheeler derived his notion of the participatory universe, created by observation, both in the present and the past.  (And, one might ask, what happens if you go far enough back in the past that no observer was present--but more of that below.)

The delayed choice experiment has been realized experimentally.  Rather than using two slits, half-silvered mirrors provide the two paths--reflection and transmission, and a technique called quantum erasure provides the delayed choice of measurement type.   The results are as Wheeler predicted in his gedanken experiment.   The observer controls the choice of quantum entity behavior  by his choice of measurement technique, even if the decision point for the observer is after the decision point for the quantum entity.

Now, there's been a fair bit of physics (mostly hand-waving) up to now, but no theology or philosophy.   What are the philosophical/theological implications of the delayed choice experiment?   I believe this has been best expressed by the American physicist Raymond Chiao, in his article "Quantum Non-Localities: Experimental Evidence" in Quantum Mechanics--Scientific Perspectives on Divine Action, V.5  (publ: Vatican Observatory and Center for Theology and Natural Science;  see below for link).

"I shall assume as a basic principle that the universe we live in bears witness to the Creator who created it  (emphasis added)...let us generalize Berkeley's philosophical principle to a 'neo-Berkeleyan point of view' in which God is the Observer of the universe, in the quantum sense of 'observer'This generalization starts from small systems...in which an observer created reality is seen to occur upon every elementary act of observation, and ends up with large systems--in particular with the entire universe.   In this viewpoint, every elementary, individual quantum event...is a result of a creative act of the universal Observer, in which all properties of all particles come into existence on their observation, in continual acts of creatio ex nihilo, which constitutes a kind of creatio continua  occurring everywhere at once.   Thus the existence of the universe itself is contingent upon the continual observations of the Creator.   The idea of contingency of existence, in the sense of the utter dependency of the universe for its properties and existence at each moment upon its Creator, is thereby introduced via quantum physics into philosophy and theology ...Furthermore, this viewpoint suggests a new meaning of the immanence  of the Creator with respect to creation, since God is acting everywhere at once in the universe.   Thus God is omnipresent, omniscient, and omnipotent...The neo-Berkeleyan viewpoint introduced here suggests not only a continual creatio ex nihilo qua creatio continua by an immanent Creator, but also a singular creatio ex nihilo by a transcendent Creator.   Moreover, the above Einstein-Podolsky-Rosen effects imply a quantum non-separability, which ties together the universe non-locally as a whole.  This reminds one of the words of the Apostle John,'All things come into being through him, and without him not one thing came into being that has being.'  (John I:3)and of the words of the Apostle Paul,'All things have been created through him and for him...and to him all things hold together.' (Colossians I:16,17)...We infer that 'all things' refers to the universe.  Not only are all distant parts the universe woven together throughout space, but also its future and its past are entangled throughout time, as if the universe were one seamless garment."

I'll await comments from readers, and add several of my own: 1) quantum effects are not generally observed macroscopically because of decoherence effects, that is to say Schrodinger's Cat would exist only on an atomic scale; 2) the notion of creatio continua is, I believe, consistent with Catholic doctrine, and was proposed by St. Thomas Aquinas; 3) Does Chiao's last sentence imply the universe is deterministic, a block universe,  and that there is no such thing as Free Will?  (A subject for another blog?)

REFERENCES
Robert J. Brecha, Schrodinger's Cat and Divine Action
Nicholas T. Saunders, Does God Cheat at Dice? Divine Action and Quantum Possibilities  (note: you can upload the pdf file)
Richard Feynman, Quantum Mechanical View of Reality, Part 1; Quantum Mechanical View of Reality, Part 2.
Quantum Mechanics--Scientific Perspectives on Divine Action, (Eds: Robert John Russell, Philip Clayton, Kirk Wegter-McNelly, John Polkinghorne), Notre Dame University Press (Note: click on the violet icon for the book Quantum Mechanics and chapters to link will appear.)
Bruce Rosenblum and Fred Kuttner, Quantum Enigma

Quantum mechanics and the Real Presence--What reality should we believe?

Tantum ergo Sacramentum                 Down in adoration falling
veneremur cernui;                                  Lo! The sacred Host we hail;

et antiquum documentum                     Lo! O'er ancient forms departing
novo cedat ritui;                                       newer rites of grace prevail;
praestet fides supplementum               faith for all defects supplying,
sensuum defectui                                      where the feeble sense fail.

 OF MIRACLES AND MYSTERIES.

A little over 20 years ago, shortly after I had decided to enter the Church, I was being catechized by a very learned and wise priest (this was before the days of RCIA classes).  As a physicist, I was struggling with the notion of trans-substantiation, that by the action of a priest a wafer could be changed into the body and blood of Our Lord.     Our  pastor first asked whether I believed in the resurrection;  I said I did, and he said if I could believe in that miracle, why not in another one?   He then told me that while one might occasionally have doubts or concerns about a particular Church teaching, one was, nevertheless, required to maintain any article of Dogma as being possible (Fr. McA--forgive the faulty memory of an old man for phrasing this less elegantly than you did.)   Several weeks after this discussion, my doubts about the Real Presence were wiped away: during a 40 Hours procession  the Monstrance was being carried in to the accompaniment of Tantum Ergo;  I remembered enough of my high school Latin to translate the verses as they were sung, and as "praestet fides supplementum sensuum defectui" rang out, my heart filled, tears filled my eyes, and I knew without a doubt that the little cracker in that beautiful monstrance contained the body and blood, divinity and humanity, of Jesus Christ.  Amazing Grace!

I was reminded that the Eucharist is a continuing miracle and a mystery, after reading an article by Alicia Colon about a recent eucharistic miracle in Argentina:  a consecrated host changed into human heart tissue, verified by witnesses and by pathological examination of the tissue and DNA (please go to the link for a more detailed account).    There have been other Eucharistic miracles (see the Real Presence website ) confirmed by the same rigorous process the Church uses to confirm miracles for canonization.     Since faith is at the root of our belief in the Real Presence, my point in this blog is not to use such miracles as evidence, but to understand (in the spirit of St. Anselm--"faith seeking understanding") what underlays the continuing miracle of transubstantiation,

In that spirit, to understand what faith had already confirmed, I delved into the works of St. Thomas Aquinas and later theologians, Edward Schillebeeckx and Karl Rahner.   (Dear reader:  please be patient--quantum mechanics will rear its ugly head later.)   To this philosophical novitiate, the concept of "substance" was murky;  on the other hand, the term "accidents"--the physical attributes of a thing, as apprehended by the senses either directly or via instrumentation--was clearly defined.  One could proceed all the way down to the properties--the "accidents"--of the sub-atomic constituents of the Host, quarks and all, and find they had not been altered by the act of Consecration.  Then what would be the substance of the Host, before and after Consecration?  It occurred to me that "substance" just told us what a thing is, no matter what its appearance seemed to be and that in the Consecration, transubstantiation corresponded to the change of the "real thing--substance" from bread to Jesus Christ. To illustrate this notion for religion classes I gave to Catholic prisoners (nothing like a captive audience!), I used the following example:  holding up a twenty dollar bill I asked the class if that bill was not issued by the government but by a counterfeiter with the same kinds of paper, ink, etc, would it still be a legitimate twenty?   And of course, they all answered no.  (I've come later to realize that this example comes dangerously close to the heretical notion of the Real Presence coming about through transignification--see the links above.)

How then does quantum mechanics relate to the Real Presence?   This question didn't enter my mind until I read a comment by Prof. Stephen Barr (a physicist whose opinions on science and the Catholic faith I greatly respect) refuting a Jesuit priest's contention that modern physics has made transubstantiation a meaningless notion.   As I interpret his article, Barr argued that what quantum mechanics told us about physical reality was irrelevant to the truth of transubstantiation (a metaphysical reality?):

"In short, one can explain the doctrine of transubstantiation and distinguish it from other beliefs about the Eucharist without any use of the Aristotelian apparatus. I don’t know what quantum mechanics has to do with any of this. If anything, quantum mechanics makes a straightforward connection between what appears empirically and what is “really there” more obscure than it was in Newtonian physics, and to that extent would make it easier rather than harder to affirm the doctrine."

Before exploring this implied distinction between the knowledge of reality from science and from philosophy/theology, I'd like do a brief horsies-and-duckies discourse on quantum mechanics. (See the reference below * for a more complete account.)  First, quantum mechanics is itself a mystery: as the great physicist Richard Feynman remarked, "I think I can safely say that nobody understands quantum mechanics."    The theory gives probabilities for alternative results of experiments, probabilities that are confirmed to a high degree of accuracy (much like actuarial results--one may not know when any given person may die, but one does know that among a large number of 70 year old men, a well-defined percentage will die in the coming year).   Even though quantum mechanics is deterministic in a statistical sense, this probabilistic character bothers many physicists: Einstein himself opposed the probabilistic interpretation of quantum mechanics, insisting that "God does not play dice with the universe".

Second, from the beginning of quantum mechanics, scientists have posited a connection between the conscious mind and the role of the observer in determining quantum mechanical outcomes in experiments.  As d'Espagnat puts it, "The doctrine that the world is made up of objects whose existence is independent of human consciousness turns out to be in conflict with quantum mechanics and with facts established by experiment."   The conscious mind of the observer plays a role in making a choice of experiments and what is to be observed.  One interpretation of quantum mechanics,  proposed by John Wheeler and Raymond Chiao,  has it that the observer creates reality by the act of choice in doing the experiment.   Since Chiao's  article on this in the collection of papers on the Vatican sponsored conference, "Quantum Mechanics--Scientific Perspectives on Divine Action (Vatican Observatory Publications, 2001) is hard to access on the internet, I'll quote from a Counterbalance review of the article:

"He (Chiao) supports a “neo-Berkeleyan” point of view in which the free choices of observers lead to nonlocal correlations of properties of quantum systems in time as well as in space, giving Berkeley’s dictum, esse est percipi, temporal as well as spatial significance. Theologically he uses this generalized Berkeleyan point of view to depict God as the Observer of the universe. Here God creates the universe as a whole (ex nihilo) and every event in time (creatio continua). The quantum nonseparability of the universe is suggestive of the New Testament’s view of the unity of creation."

So, where does this lead us in understanding how quantum mechanics explains the Real Presence of Jesus Christ in the Eucharist? I'm not sure. I reject those mystical interpretations of quantum mechanics exemplified in "What the Bleep" and other works entangling Eastern mysticism with quantum mechanics--whatever the truths of their insights into Buddhism or other Eastern religions, they have no clue as to what quantum mechanics is about. On the other hand, as the French physicist/philosopher Bernard d'Espagnat has suggested, there is a "veiled reality" underlaying the mysteries of quantum mechanics, a reality which suggests the existence of God. But because there is also a mystery in the Eucharist, it does not mean that this mystery, the Real Presence, is explained by a quantum mechanical veiled reality. It may be that the perceived, but yet unknown relation between consciousness and quantum mechanics is that which will enlighten us, tell us how the metaphysical reality of transubstantiation is totally confirmed in physical reality, a physical reality that the Patristic Fathers acknowledged but did not bother to explain. And, finally, as my wife put it: "Aquinas said that God is rational; what we don't understand is not because it's beyond reason, but beyond our rational capacity."

*The best reference for a lay person on the quantum mechanical mystery is a fine book by Rosenblum and Kuttner, "Quantum Enigma: Physics Encounters Consciousness".