Go to the blog for earlier parts.
Now is the time to recap on what concepts are at stake in various quantum interpretations, and the comments involving Buddhism, whether Buddhism prefers an interpretation to have this or that quality. You’ll have familiarity with most of them by now after reviewing so many experiments.
I will mainly discuss the list on the table of comparisons taken from wikipedia. Table at the interlude: A quantum game.
Meaning: results are not probabilistic in principle. In practice, quantum does look probabilistic (refer to Stern-Gerlach experiment), but with a certain interpretation, it can be transformed back into deterministic nature of things. This determinism is a bit softer than super-determinism, it just means we can in principle rule out intrinsic randomness. The choice is between determinism and intrinsic randomness.
Classical preference: deterministic. Many of the difficulties some classical thinking people have with quantum is the probabilistic results that we get from quantum. In classical theories, probability means we do not know the full picture, if we know everything that there is to know to determine the results of a roll of a dice, including wind speed, minor variation in gravity, the exact position and velocity of the dice, the exact rotational motion of the dice, the friction, heat loss etc, we can in principle calculate the result of a dice roll before it stops. The fault of probability in classical world is ignorance. In quantum, if we believe that the wavefunction is complete (Copenhagen like interpretations), then randomness is intrinsic, there’s no underlying mechanism which will guarantee this or that result, it’s not ignorance that we do not know, it’s nature that doesn’t have such values in it.
A Buddhist’s comment (basically me lah): On the one hand, we do not admit the existence of fatalism or fate, on the other hand, we don’t believe things happen for no reason. There was a heretical teacher back in Buddha’s time called Makkhali Gosala. Makkhali teaches the doctrine of fatalism. Everything is fixed, predetermined, there’s no role for effort in morality.
From sutta DN2, we get a glimpse of his teachings, which seems to include both fatalism and no causes.
“Great king, there is no cause or condition for the corruption of sentient beings. Sentient beings are corrupted without cause or condition. There’s no cause or condition for the purification of sentient beings. Sentient beings are purified without cause or condition. One does not act of one’s own volition, one does not act of another’s volition, one does not act from a person’s volition. There is no power, no energy, no manly strength or vigor. All sentient beings, all living creatures, all beings, all souls lack control, power, and energy. Molded by destiny, circumstance, and nature, they experience pleasure and pain in the six classes of rebirth. There are 1.4 million main wombs, and 6,000, and 600. There are 500 deeds, and five, and three. There are deeds and half-deeds. There are 62 paths, 62 sub-eons, six classes of rebirth, and eight stages in a person’s life. There are 4,900 Ājīvaka ascetics, 4,900 wanderers, and 4,900 naked ascetics. There are 2,000 faculties, 3,000 hells, and 36 realms of dust. There are seven percipient embryos, seven non-percipient embryos, and seven embryos without attachments. There are seven gods, seven humans, and seven goblins. There are seven lakes, seven winds, 700 winds, seven cliffs, and 700 cliffs. There are seven dreams and 700 dreams. There are 8.4 million great eons through which the foolish and the astute transmigrate before making an end of suffering. And here there is no such thing as this: “By this precept or observance or mortification or spiritual life I shall force unripened deeds to bear their fruit, or eliminate old deeds by experiencing their results little by little,” for that cannot be. Pleasure and pain are allotted. Transmigration lasts only for a limited period, so there’s no increase or decrease, no getting better or worse. It’s like how, when you toss a ball of string, it rolls away unraveling. In the same way, after transmigrating the foolish and the astute will make an end of suffering.”
Here’s the Buddha’s critique on him, from the sutta AN1:319
“Mendicants, I do not see a single other person who acts for the hurt and unhappiness of the people, for the harm, hurt, and suffering of many people, of gods and humans like that silly man, Makkhali. Just as a trap set at the mouth of a river would bring harm, suffering, calamity, and disaster for many fish, so too that silly man, Makkhali, is a trap for humans, it seems to me. He has arisen in the world for the harm, suffering, calamity, and disaster of many beings.”
In practise terms, we should acknowledge that there are causes which we can built to attain to liberation from suffering, effort is important. Causes are important. So morality observance is not wasted, it is encouraged. The law of kamma does argue against suffering happening for no cause and against suffering is fated to happen. It gives hope in that in the present moment, we can plant good seeds to ripen to good results. The patterns from old kamma by itself doesn’t predetermine all future, the input from present moment is important too.
So in choosing between determinism and intrinsic randomness, it is a toss up. If we can be assured that this kind of determinism does not lead to superdeterminism (which is basically fatalism), it’s a better choice. If not, intrinsic randomness of quantum can be made to not contradict Buddhism. The results of individual experiments cannot be pointed to have one cause or another. To see this, refer to Stern-Gerlach experiment, same set up, that is same cause and conditions, different results of up and down for each identically prepared particles. Remember the exercise in ruling out hidden variables, there’s no underlying difference between one particle and the next already, if we believe that wavefunction is complete. So this seems to violate cause plus conditions equals results in kammic teaching. Yet, it allows for the future to have different paths even if the past is exactly the same.
Richard A. Muller in his book the Physics of Now, argues that physics cannot rule out free will based on quantum phenomenon. His work as an experimental physicists allowed him to analyse pions (one of the many subatomic particles in particle physics) in particle accelerators. Two pions he had observed interfere with each other, that shows that their wavefunctions are exactly the same. So same cause and condition. However, the pions disintegrated at different times, so different results. Thus it would seem that quantum rules out fatalism if we interpret wavefunction as the complete description of the quantum system. The price we pay is, we cannot point to a reason why this pion decay faster than that one. If we light up two dynamites, they explode at the same time, not so with two identically created pions which are born in the same instance.
Also, when quantum is decohered up to the Newtonian physics, this quantum randomness hardly shows up in the macroscopic realm, well except for the radioactive decay which is used in the popular example of Schrödinger’s cat. So we cannot claim that there’s no cause for things based on mere acceptance of intrinsic quantum randomness. The results of quantum experiments are also pretty well defined to be in a range, eg. The spin result in Stern Gerlach is only up or down in the measurement axis. There’s no unpredictable thing like the electrons suddenly group together to become a dragon for no reason. So the cause-condition-result relationship can be restored, if we expand the definition of result to be quantum probabilistic range of result, and the probability distribution function is well defined and deterministic based on the experimental set up. For example, pion is created as cause and condition, result is, pion will decay. The time for the decay of pion matters not much.
Thus, there might be a stronger push to reject determinism.
Meaning: taking the wavefunction as a real physical, existing thing as opposed to just representing our knowledge. This is how Jim Baggott split up the various interpretations in his book Quantum reality.
Realist Proposition #3: The base concepts appearing in scientific theories represent the real properties and behaviours of real physical things. In quantum mechanics, the ‘base concept’ is the wavefunction.
Classical preference: classically, if the theory works and it has the base concepts in it, we take the base concept of the theory seriously as real. For example, General relativity. Spacetime is taken as dynamic and real entities due to our confidence in seeing the various predictions of general relativity being realized. We even built very expensive gravitational wave detectors to detect ripples in spacetime (that’s what gravitational waves are), and observed many events of gravitational waves via LIGO (Laser Interferometer Gravitational-Wave Observatory) from 2016 onwards. We know that spacetime is still a concept as loop quantum gravity denies that spacetime is fundamental, but build up from loops of quantum excitations of the Faraday lines of force of the gravitational field. Given that quantum uses wavefunction so extensively, some people think it’s really real out there.
A Buddhist’s comment: Well, the Buddha never mentioned wavefunctions as far as I know, so doesn’t really matters either way. Repeating the response in the motivation, the base concepts in classical theories just live in the heads of the physicists. Nature works as it is, the understanding of nature is also dependently arising, empty of inherent nature. This is how we can let go of even physics theories. Those who are more keen on practise may lean more towards seeing wavefunction as mere reflection of our knowledge rather than a real thing. As anything we deem real, we tend to attach to as we have the mistaken notion that real means permanent, reliable. As attachment causes suffering, we can save ourselves the trouble of suffering by not taking the reality of wavefunctions too seriously.
Meaning: The world has a definite history, not split into many worlds, for the future or past. I suspect this category is created just for those few interpretations which goes wild into splitting worlds.
Classical preference: Yes, classically, we prefer to refer to history as unique.
A Buddhist’s comment: The past and future strictly speaking exist only in our minds. We can only have access to the present moment, the here and now. We remember the past (and due to light speed delay, we essentially see the past light cones reaching our eyes, but in practise we call it present), we can project the future. So having split past or split futures doesn’t really matter. However, the Buddha when he relates to his past lives didn’t change his story everytime, and he didn’t acknowledge a fixed future as the discussion on fatalism above shows. Thus the Buddhist philosophy of time also fits in growing box theory of time with the past is fixed, present exist, but future is free.
So we are more comfortable with splitting the future rather than the past.
Meaning: The wavefunction is not a complete description of the quantum system, there are some other things (variables) which are hidden from us and experiments and might be still underlying the mechanism of quantum, but we do not know. Historically, the main motivation to posit hidden variables is to oppose intrinsic randomness and recover determinism. However, Stochastic interpretation is not deterministic yet have hidden variables, and many worlds and many mind interpretations are deterministic yet do not have hidden variables.
Classical preference: Yes for hidden variables, if only to avoid intrinsic randomness, and to be able to tell what happens under the hood, behind the quantum stage show.
A Buddhist’s comment: this seems like a good opportunity to insert the influence of mind on matter. We can even put kamma as a nice touch on how kammic actions, generated by the mind (intentions) can have physical effects in the world, not just mental results. However, there’s no reason to insist on it. The variables are hidden anyway, thus no way to test for it.
Meaning: That the interpretation admits the process of measurement collapses the wavefunction. This collapse is frown upon by many because it seems to imply two separate processes for quantum evolution
1.The deterministic, unitary, continuous time evolution of an isolated system (wavefunction) that obeys the Schrödinger equation (or a relativistic equivalent, i.e. the Dirac equation).
2.The probabilistic, non-unitary, non-local, discontinuous change brought about by observation and measurement, the collapse of wavefunction, which is only there to link the quantum formalism to observation.
Further problem includes that there’s nothing in the maths to tell us when and where does the collapse happens, usually called the measurement problem. A further problem is the irreversibility of the collapse.
Classical preference: Well, classically, we don’t have two separate process of evolution in the maths, so there’s profound discomfort if we don’t address what exactly is the collapse or get rid of it altogether. No clear choice. Most classical equations, however, are in principle reversible, so collapse of wavefunction is one of the weird non classical parts of quantum.
A Buddhist’s comment: This doesn’t really concern Buddhism. Irreversible, reversible, all part of impermanence.
Meaning: do observers like humans play a fundamental role in the quantum interpretation? If not, physicists can be comfortable with a notion of reality which is independent of humans. If yes, then might the moon not be there when we are not looking? What role do we play if any in quantum interpretations?
Classical preference: Observer has no role. Reality shouldn’t be influenced just by observation.
A Buddhist’s comment: Just by studying quantum physics, we are participating in it. We cannot verify if reality is independent of observer as an observer. As highlighted in the motivation, an universe without sentient beings in there is metaphysics to us, as we are limited to observation from the vantage point of a sentient being. However, this is more of a tautology we would say the same to classical physics. Does observer play a fundamental role in quantum? Maybe, maybe not. Good if there is, then there can be more serious consideration to observe what does the observer do. In meditation, we call this mindfulness of the mind. Too often we don’t observe the observer. That’s where a lot of trouble starts.
Meaning: is quantum local or nonlocal? Local here means only depends on surrounding phenomenon, limited by speed of light influences. Nonlocal here implies faster than light effect, in essence, more towards the spooky action at a distance. This is more towards the internal story of the interpretations. In practice, instrumentally, we use the term quantum non-locality to refer to quantum entanglement and it’s a real effect, but it is not signalling. Any interpretations which are non-local may utilise that wavefunction can literally transmit influences faster than light, but overall still have to somehow hide it from the experimenter to make sure that it cannot be used to send signals faster than light.
Classical preference: Local. This is not so much motivated by history, as Newtonian gravity is non-local, it acts instantaneously, only when gravity is explained by general relativity does it becomes local, so only from 1915 onward did classical physics fully embrace locality. Gravitational effects and gravitational waves travel at the speed of light, the maximum speed limit for information, mass, and matter. Quantum field theories, produced by combining quantum physics with special relativity is strictly local and highly successful, thus it also provides a strong incentive to prefer local interpretations by classically thinking physicists.
A Buddhist’s comment: Local or non local doesn’t really matter to Buddhists. There are many instances in the suttas where the devas and brahmas disappear from their realm and appear on earth to meet the Buddha. Depending on the nature of these beings, we might have claims that Buddhism allows for faster than light or not. However, the strongest motivation to disallow faster than light is the time travel conundrum. Since speed of light limits are not important or even hinted at in the suttas, there seems to be no reason for Buddhists to insist on locality, other than to adopt the concern of physicists.
Meaning: Reality is there. There are definite properties of things we did not measure. Example, the Heisenberg uncertainty principle says that nature does not have 100% exact values for both position and momentum of a particle at the same time. Measuring one very accurately would make the other have much larger uncertainty. The same is true of Stern Gerlach experiments on spin. An electron does not have simultaneously a definite value for spin for both x-axis and z-axis. These are the experimental results which seem to show that unmeasured properties do not exist, rejecting counterfactual definiteness. We had also seen how Leggett’s inequality and Bell’s inequality together hit a strong nail on reality existing. Yet, some quantum interpretations still managed to recover this reality as part of the story of how quantum really works.
Classical preference: of course we prefer reality is there. The moon is still there even if no one is looking at it.
A Buddhist’s comment: It’s not hard for Buddhists to reject counterfactual definiteness. After all, the measurement is not done, why should we expect the properties to be underlying there in waiting? This is one of the strongest thing people identify intuitively when they read about quantum physics and then Buddhism or the other way around. Similar comments from the observer role can apply here too. We cannot verify if reality is independent of observer as an observer. We cannot say reality is there without measuring it. This is also a strong push for investigation by the Buddha. He asked us to come and see, investigate his words. He even showed a method to attain to the 4th Jhana, then develop the powers to recollect past lives to verify rebirth, the powers of divine eye to see the life, action, death, results of various beings to verify kamma. Thus Buddhism is not interested in metaphysics. And insisting on properties of things to be there without measuring it seems to be metaphysics. Of course, still, we believe that kamma and rebirth still works as usual even if we don’t develop those powers to directly verify it. Thus Buddhists do believe in counterfactual definiteness for these properties as well. Perhaps we are being too hasty in abandoning this concept?
Extant universal wavefunction
Meaning: If we believe that quantum is complete, it is fundamental, it in principle describes the whole universe, then might not we combine quantum systems descriptions say one atom plus one atom becomes wavefunction describing two atoms, and combine all the way to compass the whole universe? Then we would have a wavefunction describing the whole universe, called universal wavefunction. If we believe in the axioms of quantum, then this wavefunction is complete, it contains all possible description of the universe. It follows the time-dependent Schrödinger equation, thus it is deterministic unless you’re into consciousness causes collapse or consistent histories. No collapse of wavefunction is possible because there’s nothing outside the universe to observe/ measure this wavefunction and collapse it, unless you’re into the consciousness causes collapse interpretation or Bohm’s pilot wave mechanics. It feels like every time I try to formulate a general statement some interpretations keeps getting in the way by being the exceptions.
Classical preference: Well, hard to say, there’s no wavefunction classically, but I am leaning more towards yes, if quantum is in principle fundamental and describing the small, then it should still be valid when combined to compass the whole universe.
A Buddhist’s comment: There are things outside of the universe. In sutta DN27:
There comes a time when, Vāseṭṭha, after a very long period has passed, this cosmos contracts. As the cosmos contracts, sentient beings are mostly headed for the realm of streaming radiance. There they are mind-made, feeding on rapture, self-luminous, moving through the sky, steadily glorious, and they remain like that for a very long time.
There comes a time when, after a very long period has passed, this cosmos expands. As the cosmos expands, sentient beings mostly pass away from that host of radiant deities and come back to this realm. Here they are mind-made, feeding on rapture, self-luminous, moving through the sky, steadily glorious, and they remain like that for a very long time.
In sutta DN 1, there’s more details on the first being to be reborn back into the universe.
There comes a time when, after a very long period has passed, this cosmos expands. As it expands an empty mansion of Brahmā appears. Then a certain sentient being—due to the running out of their life-span or merit—passes away from that host of radiant deities and is reborn in that empty mansion of Brahmā. There they are mind-made, feeding on rapture, self-luminous, moving through the sky, steadily glorious, and they remain like that for a very long time.
But after staying there all alone for a long time, they become dissatisfied and anxious: ‘Oh, if only another being would come to this state of existence.’ Then other sentient beings—due to the running out of their life-span or merit—pass away from that host of radiant deities and are reborn in that empty mansion of Brahmā in company with that being. There they too are mind-made, feeding on rapture, self-luminous, moving through the sky, steadily glorious, and they remain like that for a very long time.
Now, the being who was reborn there first thinks: ‘I am Brahmā, the Great Brahmā, the Undefeated, the Champion, the Universal Seer, the Wielder of Power, the Lord God, the Maker, the Author, the Best, the Begetter, the Controller, the Father of those who have been born and those yet to be born. These beings were created by me! Why is that? Because first I thought:
“Oh, if only another being would come to this state of existence.” Such was my heart’s wish, and then these creatures came to this state of existence.’
And the beings who were reborn there later also think: ‘This must be Brahmā, the Great Brahmā, the Undefeated, the Champion, the Universal Seer, the Wielder of Power, the Lord God, the Maker, the Author, the Best, the Begetter, the Controller, the Father of those who have been born and those yet to be born. And we have been created by him. Why is that? Because we see that he was reborn here first, and we arrived later.’
And the being who was reborn first is more long-lived, beautiful, and illustrious than those who arrived later.
It’s possible that one of those beings passes away from that host and is reborn in this state of existence. Having done so, they go forth from the lay life to homelessness. By dint of keen, resolute, committed, and diligent effort, and right focus, they experience an immersion of the heart of such a kind that they recollect that past life, but no further.
They say: ‘He who is Brahmā—the Great Brahmā, the Undefeated, the Champion, the Universal Seer, the Wielder of Power, the Lord God, the Maker, the Author, the Best, the Begetter, the Controller, the Father of those who have been born and those yet to be born—is permanent, everlasting, eternal, imperishable, remaining the same for all eternity. We who were created by that Brahmā are impermanent, not lasting, short-lived, perishable, and have come to this state of existence. This is the first ground on which some ascetics and brahmins rely to assert that the self and the cosmos are partially eternal.
Thus, there’s no issue with universal wavefunction, the Brahms from the realm of streaming radiance (2nd Jhana Brahma realm) might act as the observer to collapse the wavefunction of the universe if need be. By the way, the above quote shows the Buddhist conception of how the ideal of a creator God comes to be.
Anyway this universal wavefunction along with the unique history are usually not a thorny issue that people argue about when they discuss preferences for interpretations, unless they have nothing much else to talk about.
Now that we have covered the relevant concepts, the classical preferences for them and a Buddhist’s comment about them, here’s some reflection. Buddhism is generally more open compared to classical thinking in accepting many strange features of various quantum interpretations. Buddhism is also less decisive in placing bets on what the “real” interpretation should look like or have certain properties, except for the clear rejection of superdeterminism.
Thus, from here we can dash out any hope of trying to use Buddhism as a guide to select interpretations. Still, certain interpretations will resonate with Buddhist concepts more strongly compared to others, but the preliminary analysis here seems to suggest that we do not place hope on advancing the physics interpretation cases via philosophical inputs from Buddhism. What about the payoff for Buddhists? We can still go through the interpretations and then Buddhists can realise that we cannot make simple statements like quantum supports Buddhist philosophical concepts. Many of the interpretations might not be relevant or resonate with Buddhist concepts and some might resonate strongly. It’s important to keep in mind that as interpretations, experiments had not yet been able to rule one or another out yet, and it’s a religion (personal preferences) for physicists to choose one over another based on which classical concepts they are more attached to.