This referenced paper seems like primarily a theoretical modelling paper (almost all of its figures are simulations?) that contains as far as I can read 3 (!) actual experimental measurements in bulk on a fluorospectrophotometer. The claim is that the observed increased fluorescent quantum yield (QY) of microtubules over tubulin can be explained by the ideas in their simulations.
It's hard to buy that their proposed stories are the simplest explanation for these few measurements. Much more boring phenomena can influence QY. e.g. simply occluding fluorophores from the bulk solvent can have a huge influence on QY and spectra. (I used to design biological fluorescent reporter reagents...)
The paper itself[0] is a little (hah!) over my head, but this[1] tickled me:
> I’ve heard more than one person say that what a pity that Penrose fell for this crazy Hameroff person. But, well, I’ve met both Penrose and Hameroff and they’re both crazy of course, but neither of them is stupid.
The important thing in that paper is not "quantum", but the claim that internal data transmission by light within neural systems is a thing. The paper cites this result on ultra-weak light emissions from neurons.[1] The paper is behind Elsevier's paywall.
So the paper then takes data transmission by light as a given, and goes on to hypothesize structures that direct light as fiber optics do, and from there goes on to "ultrafast" data transmission.
Comments from biochemistry people would help here. It's not at all clear what's an actual result and what's hand-waving. However, it is clear that this is an area where experimentation is possible. Further work should move this out of the range of speculation and either confirm or dismiss it.
Given that the brain is a physical object subject to all quantum effects, wouldn’t the novelty be that it doesn't use quantum effects? That it does sounds obvious.
Words are intended to cut up the world - this is how they get their meaning. If you’ve taken these words to apply to everything in the in universe, you’ve rendered them meaningless, which is not the intention. Projectiles are subject to quantum effects but you can model their behaviour classically perfectly well. A charitable reading would be something like “to model the operational behaviour of the brain, classical mechanics is insufficient”.
"Whatever it is" == the same neurophysical/genetic factors that cause high development of "STEM" intelligence is associated with inability to process social cues in a dynamic fashion, somewhat related to high function autism. A great preference for clear classification that is not self-contradicting.
There are plenty of spaces that have the type of people the thread is describing and yet almost none of them have the type of behavior that the audience of this website loves to exhibit.
I’m sorry, but your projectile example is just terrible. We’ve known for decades that the proper functioning of many (most?) enzymes depend on quantum effects. Your body would just break down otherwise.
Quantum mechanics is needed to explain any microscopic phenomena in chemistry and biology - that is not at all in dispute.
The odd set of claims is that somehow biology has 1) figured out how to preserve long-range entanglement and coherent states at 300K in a solvated environment when we struggle to do so in cold vacuum for quantum computing and 2) somehow still manages to selectively couple this to the -known- neuronal computational processes that are experimentally proven to be essential to thought and consciousness.
This more or less amounts to assertions that "biology is magic" without any substantive experimental evidence over the last thirty years that any of the above is actually happening. That's why most biophysicists and neuroscientists don't take it at all seriously.
I am a complete lay person, so I feel a bit silly challenging someone who is clearly an expert, but the idea that a physical process that has had countless trillions of generations of mutation and change, "figuring out" how to use an underlying feature of the universe to optimise, isn't far fetched at all.
It seems that the most powerful force in the universe is simply, survival of the fittest.
Yeah, a bit like when I try to lift my leg, I actually think about how to activate my neurons so that muscle fibers contract one by one...
That's definitely not what happens.
That at some level we have quantum phenomenon doesn't mean that everything occurs at the quantum level.
“Quantum effects” usually refers to coherent states of superposition. In an environment like the brain that is suffused with photons (it’s warm), if nothing else, superpositions decohere virtually instantly. It’s therefore implausible that quantum effects could play any appreciable computational role in the brain.
When these claims come up they don't mean that they are using quantum effects to do normal atomic and molecular things, but rather that somehow quantum effects are used in the process of "cognition" thus allowing us to believe that we are in fact more than biological machines and leave room for various magical properties we like to think we have (souls, consciousness, free will, etc).
While quantum effects have been found to aid in photosynthesis, interesting uses in cognition or otherwise are in fact extremely rare in biology. I believe photosynthesis is one of the few documented examples. Also, despite the popularity of the quantum brain idea, no one has been able to show definitive evidence of it for decades now.
TLDR yes it would be incredibly novel if this claim were proven to be true.
"Soul" I think is basically the memories in our brain. And memories are data, like a picture of bits some of which are on and some of which are off. Is there a picture or just random noise? If there is picture, there is soul.
Another way of thinking about it is that a picture is made up dots which are NOT lit up. So our memories, our soul is is not "physical". It does not have mass, because whether a dot is lit up or not does not change its weight. Memory is not made up of particles but by the information encoded by their positions.
Perhaps the title should have been "Brain uses Quantum effects in a useful/controllable way". Sabine explains it well in the video. To use quantum effects for computation, you'd need very controlled conditions and it was thought be to not possible in the brain.
If so, that's too restrictive. The interaction between two He atoms needs QM (dispersion forces). Heck, even two water molecules interacting is a QM even if you decide to classify the polar attraction as purely classical. You'd still be omitting a lot of the interaction energy.
I see no way I can simulate catalyzed (enzyme) breaking of a chemical bond without:
Well duh, my point is that Newtonian physics is a subset of QM, but doesn't need to be. In fact it's an important result in QM that QM becomes Newtonian in the limit.
Chemistry, on the other hand, is QM. All of it. You can empirically get around it like alchemists did for a while. But it sucks.
This is partially why chemists accepted the existence of the atom far (far) earlier than physicists who stuck with continuum theories - their empirical methods were banging against the wall.
I think -- roughly speaking -- Penrose argues that human capabilities such as transductive reasoning are clearly not computable, therefore falsifying the idea that the mind reduces to an algorithm. He then goes on to propose how nonetheless what the mind does might be physically grounded, even if not in purely computational machinery.
I think the interesting question here is whether Penrose is claiming that the things of which the brain is capable (most notably the production of consciousness) are inherently non-computable by _any_ kind of artificial device, which is effectively a form of vitalism, or whether he is claiming that they _might_ be computable, but only with a quantum computer.
If it's physically grounded then it would be computable by some machine, just not necessarily a Turing machine. For instance, a hypercomputer can solve the Halting problem for Turing machines. We just have to be clear about the kind of machine on which a problem is computable.
> If it's physically grounded then it would be computable by some machine, just not necessarily a Turing machine.
What makes you think that? The overwhelming majority of functions aren’t computable. The evidence suggests, if anything, that the universe is uncomputable and at best some isolatable well-measured specific phenomena can have approximations computed to some arbitrary but inexact precision.
Because if it's physically grounded then you can build a physical analogue of it.
> overwhelming majority of functions aren’t computable
By Turing machines, not by any other type of machine. As I said, if hypercomputers exist then they can solve the Halting problem, which Turing machines cannot.
Consider the set of functions that that map the reals onto other reals. Almost all of these functions are truly random, with no way of expressing them that does not require the storage of an infinite number of infinite strings.
Not only is there no practical way of creating such a thing, most formulations of physics preclude any possibility of making one by placing finite limits of the amount of space or time accessible to us.
(Not to mention that almost all reals are [Turing] uncomputable in their own right, but that's a more complex thing to demonstrate.)
It depends on if the universe is fundamentally deterministic or not. Right now we don't have any way to see beyond the apparent randomness in quantum mechanics and we probably never will. This part of the universe might be completely non-computable to us, it's just random.
Randomness doesn't have any real impact on whether a problem is computable. Just model the distribution of the random variable. Non-deterministic Turing machines are a thing.
That's true. I suppose it comes down to what exactly is meant by "is computable". I don't think it was defined well enough, which I suppose is to be expected when discussing these topics that involve lots of hand-waving.
I interpreted it to mean that we can predict the outcome of it, you interpret it to mean that we can model it.
Either way, maybe it doesn't matter since the original proposal is that consciousness is a subjective experience and there isn't an obvious way to define how to programmatically create it i.e. compute it.
You probably mean probabilistic Turing machines. Non-deterministic automata in general don't involve randomness, and the results of their computation are considered to be deterministic despite the name.
And of course all TMs are just theoretical models. Non-deterministic Turing machine equivalents in particular don't physically exist and may be physically impossible.
But of course if there is indeed true randomness in nature that needs to be modelled, that same randomness can be used a source of true randomness for computation, and you can then build computation that does have stochastically determined results.
In your statement, I'm not sure by which definition physically grounded things are a sufficient condition for being computable, but I think Penrose depends on the Turing notion of computability and the hardness of the halting problem.
We can of course move goal posts, redefine computability however we like, to get whatever conclusion we care for, but I think that Penrose effort is intellectually honest.
For that to be uncomputable brain must run the halting problem algorithm, which it doesn't, because the halting problem algorithm needs infinite memory. Being finite, brain has finite number of states, which all can be enumerated in finite time.
That wasn't the impression I got from Sabine's video. It's consciousness itself (the subjective experience) that isn't computable (AI will probably never be conscious).
Would you say that philosophical zombie is computable? AFAIK dualists agree that philosophical zombie is impossible in this universe, which means what is computable is a conscious being.
There are several biological processes for which we're fairly certain that some quantum mechanical process is exploited. Strictly speaking, everything about biology is ultimately explained by quantum chemistry and physics, but not in a particularly exciting way. However, I don't think anybody has found any concrete evidence that any process in biology exploits entanglement. Instead, the examples we've seen so far are mostly around tunnelling, and coherency.
People argue a lot about the "meaning of quantum" but nearly all the arguing is about the behavior of entanglement and wavefunction collapse. Tunnelling and coherency are pretty banal QM phenomena at this point.
As for Sabine... I don't find her popular science vides about biology to be particularly enlightening or accurate.
Not at all! There is evidence of quantum effects in the light harvesting complexes in chlorophyll that operate at ambient temperatures. This appears to be a key element to the efficiency of guiding photons to the photosystem.
I honestly think that mosquitoes might be already exploiting a quantum
effect while flying. For example, when you're not looking at them directly
or when they fly in a chaotic manner to avoid being seen, they seem to
disappear and reappear in different locations, traveling through
space-time.
I'm always amused by the lack of creativity of biologists.
It seems every decade or so some closely held dogma of biological systems is proven wrong after they mock physicists, computer scientists or mathematicians who first suggest it.
I suspect a lot. He has unorthodox views on lots of topics. For one he doesn't seem to believe in the heat death of the Universe. He has some interesting theories in regards to gravitational waves and so on.
> he doesn't seem to believe in the heat death of the Universe
I’m not sure I believe that the heat death of the universe really is the end of all things forever and for all time either, after reading Asimov’s The Last Question and a particularly fantastic manga oneshot adaptation by manga artist Ryul.
If you haven’t read it, I can’t recommend it more highly, and the manga version is a nice addition to the canon. I found a version narrated by the man himself on the Internet Archive, and I also found a fully voice acted audio version from the Drabblecast, also linked below.
One interesting angle I've heard proposed with regard to this is that even post-"heat death", there is no guarantee that local pockets of low entropy will not exist. Indeed - quite the opposite is true: let's say being in a maximum-entropy state requires all particles to assume a fully random distribution (otherwise a potential gradient would exist somewhere, a form of order, and the entropy would not be maximized). Now, take a description of an NxNxN chunk of universal "stuff" (energy, matter, etc). Similar to how we can find every string of digits in Pi if we look long enough (each given substring is equal to the search string with probability 1/10^N, N is length of string), we should be able to find every possible chunk in the maximum-entropy universe, with the probability for any given chunk matching being 1/M^N^3, (M is the universal "base", how many options a given location has for what it can be in the encoding we are using).
Long story short, assuming an infinite universe post-"heat death", we'd expect to be able to find every possible arrangement of particles represented at some location, even very complex ones such as the entire universal state we observe today.
I've heard these theoretical ideas advanced also, perhaps in writings by Richard Dawkins but I'm not sure; iirc the idea is loosely related to the concept of quantum foam but I may be mistaken.
> Quantum foam or spacetime foam is a theoretical quantum fluctuation of spacetime on very small scales due to quantum mechanics. The theory predicts that at these small scales, particles of matter and antimatter are constantly created and destroyed. These subatomic objects are called virtual particles. The idea was devised by John Wheeler in 1955.
It's important to remember though that these words, i.e. "virtual particles" are just words used to convey a-priori what are purely mathematical constructs. It in no way is declaring that such things are tangible instances (e.g. detectable in a cloud chamber or through other empirical means.)
These future states may as well be parallel universes, however: there's no real way for them to interact with each other across the vast time and space of maximal entropy.
Why is the link to this blog spam instead of to the paper or a better article? Hossenfelder lacks qualifications in neuroscience and is often confidently inaccurate.
There is a lot of intelligence in plants. For example crown shyness, navigating to water, trees informing each other that a giraffe is eating their leaves, etc.
None of that is what I'd call "a lot" of intelligence, not even in aggregate.
(Evolution itself can be described as a form of intelligence, but evolution is as different from individuals as humanity collectively is from a single thought).
If the brain can get any extra fitness from exploiting quantum effects, it will. But the reason people are interested in this stuff seems to be that they think there's a connection between the quantum nature of the brain and consciousness. I don't see how the argument is any more than this:
For a popular survey of the relevant neurophysics, try Stairway to the Mind by Alwyn Scott (1995). He argues it is very unlikely that quantum effects are relevant, and is skeptical of Penrose.
Quantum effects allow for randomness which is nice since it gives some sense of not being a machine entirely on rails.
That alone alone doesn't give determinism though. For that we
still need to have some influence on the outcomes of quantum events. If there's a mechanism by which we can will for some quantum outcomes to be more likely than others that'd be nice. It'd fit with intuition that we aren't just observers of a series of events but actual participants that determine the outcome.
I find the notion that free will requires a non-determistic system strange. Consider for the sake of argument that you love apples and hate oranges. Then given a free choice between an apple and an orange, you'll always pick the apple. The system is determisitic, and your free will is what makes it deterministic. On the other hand, if you were required to choose an apple or an orange based on a coin flip, you wouldn't call that free will.
There’s an excellent 2hr or so podcast episode on free will that has drastically changed my mind on the notion of determinism. The main argument is that the notion of “choice” is in fact an illusion and when you dive into what you’re actually doing when you “choose” you realize that it’s really just determinism under the hood.
In other words a deterministic universe is actually completely consistent with our experience once you realize that the mechanism of us “choosing” anything is really an illusion.
For some reason, most opinions on this topic that one reads on forums with of technically inclined people are non-compatibilist (the view that causal determinism and free will are mutually exclusive) while a good number of people that think a lot about will (i.e. philosophers) are compatibilists...
Note though that in metaphysics/theory of mind determinism is defined as the state at a given moment being necessitated from the state at a previous moment. I think one could critique your argument by saying that you're just pushing back the question of determinism by one level (i.e. "what's responsible for your preference of apples in the first place?"). The fact that you always choose the same way can then be taken to be a proof of determinism instead.
A compatibilist line of argument for your position might go something like this: What we consider a free will would hardly be met by a will completely detached from any deterministic constraints whatsoever. If a necessary condition for free will was that it is free from any external conditions, what would there even be for it to 'choose', and on what basis could its choices be made? Only if your mind knows of apples and oranges (objects subject to deterministic systems) and can interact with them (is at least partly part of the same system) can it make a meaningful choice between them. (Again, this view is based on the assumption that determinism exists and that free will is possible.)
Looking in the past doesn't change much, because the agent exists in the past too and is a cause of the present agent. But choice really happens in present, so distant past is a wrong place to look at, but if you look in the wrong place it's expected that you don't see anything.
Sometimes I wonder if those non-tech philosophers are actually smart or they're just free-running their hallucinations with entire System 1 and circular reasoning detection turned off, just because doing so allows them to generate more plausible text faster for stronger in-group approvals...
Isn't the concept of free will somewhat of a mysticist mental pleaser that it'll be the thing that save us in the end in doomsday scenarios? If we accept that the world is deterministic and so are our minds and behaviors, that will be quite depressing, and if we assume free will and our souls are real, that means decisions we make comes from trekky super-reality and therefore potentially infallible, which happy.
> Note though that in metaphysics/theory of mind determinism is defined as the state at a given moment being necessitated from the state at a previous moment. I think one could critique your argument by saying that you're just pushing back the question of determinism by one level
I think this is just tangential to free will. If a state_old -> state_new transition() was deterministic code, but code involved RNG sampling, it can be considered both deterministic and not. It cannot be ruled one way or another here.
> What we consider a free will would hardly be met by a will completely detached from any deterministic constraints whatsoever. If a necessary condition for free will was that it is free from any external conditions, what would there even be for it to 'choose', and on what basis could its choices be made?
This part looks like a strawman sandcastle made up to overload opponents. A lot has to be defined in your favor for that argument to work. What's wrong with rolling a dice(assuming it still works)? Is randomness make a choice laughable meaningless non-choice?
I'm starting to understand why "technically inclined people are non-compatibilist", everything is just way too under-defined that people are barely on same pages.
Supernatural or nonexistent is false dichotomy fallacy. The third option is free will exists and natural. Many things follow this pattern: flat earth, geocentrism, lightning, soul.
Someone who hates oranges might still, on rare occasion, pick one. Maybe they’re having a bad day, misunderstood the instruction, or wanted to turn their life around starting now. We might make decisions with high likelihood but it’s a qualitative leap to go from 99.999999% to 100%.
There’s always more context to a choice than a simple question, but we aren’t limited to vague questions.
What you ate for breakfast January 3, 2024 could be what you always eat with those memories, that body, those resources etc. So saying yes once could very well mean you would say yes 100% in exactly that context without meaning you would always say yes in similar but not identical situations.
On the other hand if it’s random in identical contexts then it’s just random not free will.
The question is rather what circumstances gave rise to the system that would make a given choice. Thats all "free will" is: the current state of a system that gives rise to a specific choice.
Free will as its commonly understood is an entirely religious concept and has little/no utility in explaining behavior. It is, IMO entirely unrelated to consciousness and a distracting subject that traps people into circular reasoning.
Its the state of a system that gives rise to the contemplation. Nothing is free from determinism its determinism all the way down.
The interesting question is what are the myriad factors that contribute to the state of a system at a specific time. From hormones to shoe color to genes to what you ate for breakfast to how you were raised.
Yeah psychology is interesting but not only does it not really have anything to do with the article but it also doesnt provide anything particularly compelling as far as the whole question of "free will" goes.
It's relevant, because if agent's contemplation gives rise to a specific choice, it means the choice is determined by the agent, and thus the agent controls the choice and is responsible for it.
Yes this is true. Also the agents choice depends entirely on the state of the agent at the time it makes the choice. The contemplation is just another process that is determined by the state of the system. Like I said its interesting and theres a whole field of study for this but as far as this post and the question of free will go its entirely irrelevant.
Because as I've said above, the state of the agent determines what choice it will make. The state of the agent is determined by outside stimuli just like everything else. This conversation here is a great example why I consider the idea of free will to be mostly a religious concept and a thought-trap.
Like I said before the more interesting questions are about the interaction of a system with the rest of the world such as what brought the system to a state that it makes a certain choice, what are the dynamics of that state, how might that state change based on different stimuli, can we nail down what exactly is going on in all the relevant parts of the system at a given time etc and if not how close can we get.
Ive got nothing against free will. Its just an idea thats important to some religious beliefs. Its just kind of pointless to talk about when were talking about neurology and the source of consciousness.
I do wish the ever increasing stigma around it in serious conversations would hurry up and increase so we could stop wasting our time with it though ;)
Indeed. The problem is that the word "free" has different meanings when talking about free will and freedom in other contexts. What you talk about is value freedom, while ppl denying the existence of free will refer to "physcial" freedom. Few ppl notice the distinction though which makes the debate somewhat strange.
One thing that's really strange about this article is that it presents compatibilism and incompatibilism as having a different concept of 'free will' – compatibilism sporting an everyday sense of free and incompatibilism roughly a more scientific one. The article assumes incompatibilism to be correct on those grounds and goes from there. Coming from the philosophical literature, this is simply not the case. If both sides assume the same definition of free will, e.g. as "the agent could have chosen differently", they still have a genuine disagreement...
Well there are many versions of compatibilism I guess, but just reading the Wikipedia article on compatibilism I don't think most compatibilists think freedom relies on whether or not causal determinism holds. Please tell me if i'm wrong.
Defining free will:
Compatibilists often define an instance of "free will" as one in which the agent had the freedom to act according to their own motivation. That is, the agent was not coerced or restrained. Arthur Schopenhauer famously said: "Man can do what he wills but he cannot will what he wills."[14] In other words, although an agent may often be free to act according to a motive, the nature of that motive is determined. This definition of free will does not rely on the truth or falsity of causal determinism.[2] This view also makes free will close to autonomy, the ability to live according to one's own rules, as opposed to being submitted to external domination.
https://en.wikipedia.org/wiki/Compatibilism
> don't think most compatibilists think freedom relies on whether or not causal determinism holds
I guess it is technically true that they would be okay if it turned out determinism was false, since their argument is that determinism and free will CAN be true at the same time. Their line of argument is only really worthwhilein the first place if you believe it plausible that causal determinism holds. And I think most of them do (maybe it's telling that the position is also sometimes called 'soft determinism'). If they denied determinism from the outset, they'd probably be in the 'libertarianist' camp instead (not to be confused with political libertarianism).
The 'tree' of positions relating to determinism & free will is roughly:
Do you believe determinism and free will to be mutually exclusive? If no: you're a compatibilist. If yes: you're an incompatibilist. -> In which case: do you believe determinism to be true OR do you believe free will to exist? You believe determinism is true: you are skeptical about free will, to you free will is an illusion. You believe free will to exist: You're a libertarianist and believe complete determinism not to be true.
Although often much lengthier and more technical than Wikipedia, the Stanford Encyclopedia of Philosophy has very well-vetted entries on philosophical topics, where the authors all are scholars in the respective topic and are asked to write introductory entries (potential downsides: English only and not always completely novice-friendly). There is one on compatibilism, too https://plato.stanford.edu/entries/compatibilism/
Yes, the Stanford Encyclopedia of Philosophy is great! (and it is referenced in the paper)
A quote from it: "Other compatibilists show less concern in rebutting the conclusion that the freedom to do otherwise is incompatible with determinism. Compatibilists of this stripe reject the idea that such freedom is necessary for meaningful forms of free will (e.g., Frankfurt 1969, 1971; Watson 1975, Dennett 1984)—the “varieties of free will worth wanting,” (Dennett 1984). And even more notably, some compatibilists simply deny that freedom of this sort is in any way connected to morally responsible agency (e.g., Fischer 1994, Fischer & Ravizza 1998, Scanlon 1998, Wallace 1994, Sartorio 2016)."
This is the position of the paper above essentially. It references Dennett. The kind of freedom that matters, and that ppl are talking about in everyday life, is not the type of freedom incompatibilists reject. It still makes sense to talk about freedom, as in "freedom of opinion" etc, even if agents could not have chosen differently.
The paper explains this position from the perspective of reinforcement learning, and also gives a theory for why it is beneficial for intelligent agents to model themselves as being able to have chosen differently even if they actually could not.
Compatibilists often argue that determinism and free will (and moral responsibility) are compatible since their view is that what constitutes freedom is not affected by whether or not determinism holds. Hence, in this case, the debate is not about the consequences of determinism, but rather what freedom is.
In my mind, that the known laws of nature do not permit "free will" in the way incompatibilists define it is trivial. (regardless of whether the universe is truly deterministic or also has some randomness sprinkled on top)
Instead it’s a machine on a roulette table? There is no third state between determinism and randomness. Either something has a cause, or it doesn’t, and hence is random (or a combination of both).
> actual participants that determine the outcome.
Nobody disputes that we are (well, almost nobody). But we as participants are ourselves an outcome of processes that are somehow determined, and our decisions have causes. And assuming that they’re instead random doesn’t improve the situation.
There's four states. Randomness vs deterministic. And then within randomness the possibility to influence outcomes vs none.
A purely deterministic mind is a movie. You watch it. There's no way to influence the outcome or it wouldn't be deterministic. You're just a long for the ride.
A non deterministic mind could be nothing more than randomness with no ability to influence outcomes still which makes it little different to a movie. Again you're just a long for the ride even if the ride has random events.
But non deterministic and the ability to actually influence outcomes? That's the intuition I suspect most people have for free will right there.
Influence implies causation, and hence the opposite of randomness. I see randomness vs. determinism similar to a parallelogram of forces. Every behavior can be divided into a deterministic component and a randomness component. But that’s the only two components there are. And free will doesn’t fare better with the randomness component than with the deterministic component. Randomness means you are subject to an arbitrary choice. Influence is a causation arrow from you to the thing you influence (like a choice you make). But it says nothing about the arrows pointing to you.
"Randomness" is not a correct interpretation of quantum mechanics, all you can say is that, beyond some limit, uncertainty in measurements kicks in. A deterministic process being behind it cannot be ruled out (yet?).
Hmm, we have actually ruled out quite a lot of that sort of thing... For example we're pretty sure there's nothing like a "local hidden variable", e.g. a little deterministic process in an electron determining if it's going to be spin up or spin down when measured.
No. It rules out hidden variables. The underlying theory is still deterministic: the wavefunction is entirely deterministic. The randomness is only introduced in the interpretation, and for example the many-worlds interpretation is still entirely deterministic, even if it appears random to an observer inside the wavefunction.
So the article says "quantum mechanics is incompatible with local hidden-variable theories".
Hidden variable theory is what you were describing initially. It basically says that there must secretly be deterministic rules to quantum mechanics, and that the randomness we observe is just due to our ignorance of some "hidden variables". Einstein was a fan if this theory because he believed "God doesn't play dice".
John Stewart Bell discovered that quantum mechanics would actually behave a little bit differently if there were secretly variables out there, and proposed experiments that would show if there were hidden variables or not.
The 2022 nobel prize was awarded because these experiments were finally completed, and they showed conclusively that there were no hidden variables in quantum mechanics.
>quantum mechanics is incompatible with local hidden-variable theories
>local
That's an important modifier.
>The 2022 nobel prize was awarded because these experiments were finally completed, and they showed conclusively that there were no hidden variables in quantum mechanics.
Nah, from the same article:
"The exact nature of the assumptions required to prove a Bell-type constraint on correlations has been debated by physicists and by philosophers. While the significance of Bell's theorem is not in doubt, its full implications for the interpretation of quantum mechanics remain unresolved."
Conclusively was probably too strong of a word, as there are technically still two ways to get hidden variables to work:
1) If we allow information to be non-local, i.e. we allow information to travel instananeously. Allowing this would just be such a hit to the foundation of theories like relativity and quantum field theory that most physicists don't really believe this could be an explanation. These theories rely on nothing traveling faster than the speed of light.
2) We could allow for "superdeterminism". One of the assumptions of Bell's theorem is that a researcher is free to choose any measurement they'd like, independent of the particle they're measuring. However, if the universe correlated everything from the Big Bang onward, a.k.a "superdeterminism", then the researcher is actually NOT capable of choosing a measurement independently of the particle. Everything is pre-scripted from the initial conditions of the Big Bang. If I go and measure a photon from the CMB (the earliest light in the universe we can measure), superdeterminism implies that this photon emitted 14 billion years ago somehow "knows" exactly how it'll be measured in 14 billion years, and has hidden variables that ensure it won't contridict my measurements or quantum theory. This seems to open a whole can of worms about the feasabilty of all scientific experiments, and it doesn't actually make any predictions about the randomness anyhow.
Out of curiosity I went digging to see if there were hard numbers for what physicists believe, and I found a 2011 poll from a conference about the nature of quantum mechanics. Surprisingly none of the respondents believed that random quantum events have some sort of underlying determinism. I'm not saying you should always follow the crowd, but it, combined with all the laboratory testing of the Bell inequality, shows that your initial statement "randomness is an incorrect interpretation of quantum mechanics" is not something you'd say to a group of physicists without having very compelling and detailed reasons to back it up, because it's very much a fringe idea. The majority of physicists subscribe to theories of quantum mechanics that don't involve hidden variables, and treat the randomness as inherent to theory.
Link to the poll if you're interested: arxiv.org/abs/1301.1069. I'm talking about question 1.
Those numbers suggest that 36% don't believe in fundamental randomness. And that's given the status quo that interpretations are philosophy not worth to think about so people are indulged to believe in random stuff, add to this cognitive inertia due to education largely following Copenhagen, and 64% doesn't look like a very big number. Just how implausible must be Copenhagen to lose 36% in such comfy conditions?
But the other 3 results are that the randomness is "irreducible", which I'm assuming means we can never actually get rid of the randomness. And smaller portion believe that randomness is just apparent, which I'm assuming they're referring to Many Words interpretation. Neither of those gets you to determinism from our perspective though.
They actually ask later in the poll which interpretation is their favorite (Q12) and 42% pick Copenhagen. But the only deterministic one on that list is the pilot wave theory, and that got a 0. Some did pick "other", so that might include something deterministic, but based on the results of Q1 I'm assuming not.
Irreducible, but not fundamental? If randomness doesn't exist, how your perspective matters? And why do you think ignorance can't be fixed? That's an antiscientific claim.
Bell's theorem tells you that if some hidden variable is involved it has to be non-local. That's it. Period.
It doesn't tell you there are hidden variables involved or not. Whether light travels fast or not. Whether there's determinism or random chance involved. It's only an if clause, if you may; but a very important one, I'm not detracting from it. Please take time to understand that.
>These theories rely on nothing traveling faster than the speed of light.
There's a lot of phenomena that could be perceived as "faster than light" (i.e. a shadow's projection) and yet they aren't. Information should also not travel faster than light, that put an end to many entanglement paradoxes out there that seemed to imply faster than light travel from a first glance.
If a hidden variable is involved, there could be a not-yet-understood part of the system that allows for it to work in spite of this apparent non-locality.
Does the Bell theorem tell us that? No. Do I know the answer to that? No. Do you know the answer to that? No. No one knows. Hence why I wrote, yesterday,
>A deterministic process being behind it cannot be ruled out (yet?).
Incompatibility with hidden variables doesn't imply randomness. Hidden variables theory doesn't assert mere determinism, it's a stronger assertion that particles must be classical.
Pay attention to the people with the most dogmatic views in this thread about determinism and free will. It’s extremely interesting. Typically (and strangely) I find the most dogmatic folks are mostly determinists. I think probably because it’s more “science-y” than a philosophy that has to say “I don’t know.”
Even in this thread you’ll note that there’s a very vocal group of people who would happily shout down any idea that there’s any sort of free will in the universe and that the universe is anything other than a cold mechanistic computation that was determined billions of years ago. They’ll shit talk Penrose, or shout about pseudoscience, and very few of them will critically engage with the topic in good faith. They’ve already made up their minds. Not only that but some of them (troublingly) will even talk how we’re not even conscious at all. As if we are all just meat computers or something.
Now, I don’t know if we’re conscious or not and I don’t know if the world is on rails either, but it certainly feels like I have free will and it certainly feels like I’m responsible for my actions and it qualitatively feels like I’m conscious.
Obviously, not all of my choices are made freely, but some of the ones that matter to me at least seem to be made freely. But a lot of people seem absolutely sure that we’re not making anny choices and we have no free will. It’s weird to me, because literally every day I get increasing evidence suggesting I have free will within some limits and the universe is unfathomable and unpredictable.
Not to be an ass, but if I can be honest I kinda pity the folks that don’t have that experience. I reckon if you’ve never made a decision that really mattered it would be easy to feel like it all wasn’t your choice. Maybe that’s too harsh, but anti-free will and determinism are just as untestable as any other philosophy I suppose, but I do wonder what kind of life can lead to people thinking that they’re not making any conscious decisions.
I’m a determinist and I certainly feel like I’m in control of my thoughts and actions. That doesn’t mean I actually am. I think that we as humans are just hardwired to feel like we have free will, even if we believe otherwise on an intellectual level.
I don't know how you define "determinism" but perhaps in the sense that future is determined by the past, right? The initial state of a system and the forces acting on it determine its state at some future time. Right?
But universe doesn't work tat way. Universe is non-deterministic because quantum effects happen randomly. They cannot be predicted, only their probabilities can.
That does depend on your interpretation of quantum mechanics: the wave-function is still entirely deterministic. Non-determinism is only induced by 'collapse', but it's not mandatory for this to ever happen: the many-worlds interpretation is basically the result of saying it doesn't, and is completely deterministic. (In fact 'collapse' interpretations are not particularly popular theoretically, because it's actually a blurry line of decoherance: it's just generally convenient for interpreting the outcome of a calculation, and you can assume it's a close enough approximation to experiment once your system has interacted with your detectors).
>the many-worlds interpretation is basically the result of saying it doesn't
Few problems with this, the state that a particle can be in after the collapse of the wave function follows a probability distribution, so if all states are equally real then why does it seem like some states are more likely than others? Why would probabilities be such a powerful mathematical tool, and how would it work in a MWI.
If all points of the universe branch out into several universes after each particle interaction, where does all this energy come from? If all branches are equally real why even have the wave function in the first place?
> if all states are equally real then why does it seem like some states are more likely than others?
Because some states are more probable than others. That is what the wave-function tells us. It does not give equal probability to every possible outcome.
> Universe is non-deterministic because quantum effects happen randomly.
One of Penrose's foundational arguments is that the random element of quantum collapse is deeply unsatisfactory; he thinks it's a defect in the theory that must eventually lead to its replacement by a better theory.
Einstein had a similar conviction. But from all we know now quantum description of the world is the best theory we have. Particles behave following probability distributions. There are laws (of QM) they follow, but that does not mean the outcome is deterministic. We cannot predict the outcome of quantum experiments, only their probability based on the previous state of the world. And that is not because our instruments are not sharp enough, it seems indeterminism is a fundamental part of quantum reality.
Now if the tiniest elements behave that way non-deterministically and we can assume they do have an effect on the world around them, then it seems to be the whole world is more or less indeterministic. Probability distributions can be observed that's all.
Further credence to the idea of non-deterministic world is given by Chaos Theory. A butterfly flapping its wings in Africa can cause a storm in Kansas. Therefore the indeterminism at the atomic level is amplified to the macro-level, as predicted by Chaos Theory.
And if that is the case then we can assume that what happens in our brains is also indeterministic. Thus you could say we have "free will", our wills and thoughts and likes are a product of something indeterministic. Thus you can say that "our will is free", more or less. I'm not sure what "Having a Free Will" would mean, but I can understand that our will is not wholly determined by history.
> from all we know now quantum description of the world is the best theory we have
Penrose would agree!
I think that in The Emperor's New Mind, he sets out a scheme for classifying the quality of different theories, e.g. quantum mechanics, darwinian evolution. He classifies quantum mechanics (quantum chromodynamics?) as a "Superb" theory, because of the accuracy and precision of the predictions it makes. But he still says it's fundamentally flawed.
> We cannot predict the outcome of quantum experiments, only their probability based on the previous state of the world. And that is not because our instruments are not sharp enough, it seems indeterminism is a fundamental part of quantum reality.
I know very little about QM, so I could be completely off here, but, not being able to predict the outcome of an experiment could be completely different to the outcome being deterministic.
Lay person point of view. Rewind the universe by an hour and replay. Does QM have anything to say about that? I'm inclined to think not, but I really don't know. In other words, does QM say:
1) The result would certainly be the same.
2) The result could certainly be different.
3) The theory doesn't tell us one way or another, meaning it doesn't exclude either 1 or 2 being true.
If it is 1, then we have determinism. If it is 2, then we have randomness. I don't think either of those are compatible with what people think of as free will (mysterious ability to choose outside of physics).
I think it's impossible to rewind the universe, so no sensical theory should say anything about that. A theory that theorizes about what happens if something impossible happens would seem to be waste of time. :-)
But I think the answer is: The outcome of a quantum experiment is random. So if the same experiment is repeated, it should most probably give a different answer, unless the answer is always the same, or one of only a few possibilities.
> It’s weird to me, because literally every day I get increasing evidence suggesting I have free will within some limits and the universe is unfathomable and unpredictable.
I find the whole subject fascinating, but I am not an expert. I break it down for myself in this manner, so perhaps you could give your view.
If we rewound the universe by an hour (as an example). Literally, every single thing, particle, what have you in the universe is exactly as it was an hour ago. Then you started it again (1). Would you end up where everything in the universe happened exactly as it already did? Faced with the same choices, would *you* make the exact same choices, to end up exactly as we are now?
If the answer is yes, then that implies determinism, and would probably reject what you think of as free will (I'm taking a guess, because you didn't explicitly define free will).
If the answer is no, then it appears that the choices are just random. You have all the same information, all the same moral conindrums, etc, and yet, you just chose something different. Why? In this case, if it is just random, then that also seems to reject the idea of free will.
If there is some other mechanism involved here, could you describe whether it would make the same decisions or not. And if not, then on what basis would the decisions be different?
(1) I'd really prefer to avoid nitpicky arguments about the arrow of time and so on. This is just a thought experiment.
You should define “free will” if you want to claim you have direct experience of it. I’d suggest that what you’re experiencing may be just “will”.
And in my opinion, whether you’re “responsible for your actions” isn’t a question about the nature of reality (ontological), rather a question (or one of several) about how we should act in it (moral).
I personally think of “will” as being closer to “discretion” than to “action”, but I’ll try to steer the conversation away from semantics.
What I want to focus on is what leads you to conclude that your will, or your discretion, is not deterministic. Forgetting, if we may, arguments for or against determinism from a physics perspective: what’s the argument from your personal experience?
As for morality, I would make the case that ontology should inform morality but not the other way around.
You might as well be a compatibilist. Yes, it looks like free will exists and the universe is deterministic, consequently free will is compatible with determinism. Then you can realize that the myth that free will is incompatible with determinism is just a superstition.
Am I the only one automatically thinking about LLMs here? Very wild speculation, but what if we accidentally tapped on a phenomena we actually didn't know before, some kind of "event horizon", related with the arise of consciousness and that's the underline reason about why LLMs work so well?
So there is a little quantum soul which is the consciousness of the brain. How does the soul get it's consciousness?
I think the best attitude is that a. We have no clue what causes consciousness and b. it's probably much more widespread that we previously assumed. We assume that other humans, cats and sufficiently advanced AI are conscious based on observing behaviors similar to our own. But why should self awareness be tied to specific behavior? Why not a star self aware of being a star, without having any of the same senses, drives and capabilities as a human? At best we can assume is that some other animals/things might be self aware of similar occurrences as we are.
As for quantum effects, if brain is able to leverage them in computation, that's an obvious evolutionary advantage. One obvious person of a brain is to simulate many possible potential actions and their real world outcomes. If it's able to use quantum states to model multiple scenarios simultaneously, that's quicker/more detailed modeling with less energy use.
But as far as quantum effects causing consciousness, how could we possibly tell and what useful insights have we gained by making this assumption?
Kinda weird that (if this is true) evolution is able to come up with things like this. And I'm not trying to dogwhistle for creationism here, just thinking it's weird.
The following is most likely nonsense, but I always had the intuition that there is a hidden connection between mother and child that remains after the child's birth.
The microtubules were from a pigs brain according the material and methods. These proteins exist in all animal cells. So this probably explains why single cell organisms are so intelligent despite not having a brain
Please make your substantive points without calling names (and please don't post in the flamewar style generally). This is in the site guidelines: https://news.ycombinator.com/newsguidelines.html.
As we're detached, let me say that ycombinator used to be a place that attracted the best of the best. One could come here and talk to people who knew their shit and had something to say.
I think free will is a bit like a sphere. There is no true sphere in nature, only a more or less accurate approximation. Likewise for free will, there is no such thing as true free will (tm) but there are better and worse approximations.
I'd like to think of it like pseudorandom vs random numbers generators. Does it really matter if it's a truly random algo if you can't actually see any difference within the constraints of its usage?
Likewise, our pseudo-free will is probably more than enough for having near-independent agency from the environment. Anything outside of that is probably already within the realms of metaphysics, which is unprovable by definition anyway.
Although I love your metaphor for talking with people who know about RNGs and pseudo RNGs not everybody does while everyone knows about more or less accurate spheres.
And just like free will, there are no true RNGs, just RNGs that we don't have the accuracy or computer power to predict. Quantum mechanics may disprove this.
I generally dislike the word as well, _however_ it sorta makes sense in this context since it makes sense to think about the composition of our brains (and bodies). We are, of course, meat.
That may be true, but if you see yourself as a butcher, naturally, you tend to see everyone else as meat. The OP's disregard for "dumb people" is pretty obvious.
At least Penrose himself has an excuse for this: he's actually intellectually honest and came to this from a mathematics first purely theoretical perspective - he might have been deluded by others' trashy science, but he didn't go on to delude others.
It's funny that while it's great to also keep this perspective open as an interesting theoretical avenue, and Penrose is worth appreciating as a very original thinker... all the "evidence" for quantum consciousness theories is probably pure junk sci =)
Yeah I'm a third into Penrose's book right now but I don't buy the argument. However I can see where he's coming from and he presents everything objectively, opinions are clearly highlighted as such.
Yeah I put this in the same bucket as religion and freewill. These are things people cling onto because we so desperately want to feel special and magical.
It's similar to learning that the universe doesn't literally revolve around us.
Assuming free will doesn't exist, how would a world where free will does exist be any different? As far as I can tell, our current world is indistinguishable from a world with free will, therefore our world is equivalent to one with free will.
I think you need to define free will before deciding whether or not it exists. People that argue about it are mostly just using different definitions for it. Actually, the whole thing seems to be just a semantic argument, there's no science or anything involved.
IMO, I think free will is just a lie we tell ourselves. The inner workings of our brains are mostly hidden from us. When asked why we did something we just make up some bullshit that's not unlike what ChatGPT does when it helpfully fabricates an answer for us.
Free will is the idea that there is a “you” and you are the author of your thoughts.
If you think “you” is just a bunch of neurons in the brain then most people would not consider that free will because physics is the author of your thoughts.
To be clear that is my view. So I don’t think we have free will. We just feel like we do.
I don't see how we are anything more than just the particles that make up our selves, ie. the neurons in the brain. I can't seem to find a definition of free will that isn't self referential. What does it even mean that:
> Free will is the idea that there is a “you” and you are the author of your thoughts.
I am a "me", and I am the author of my thoughts, but that comes from the neurons in my brain firing and making decisions based on input. It still makes decisions, choices. I just maintain that those choices are not outside the universe. They are either:
1) Entirely causal based on all inputs and particles in the universe. Rewinding the universe and replaying will result in the exact same decisions.
or
2) The universe contains implicit randomness and this feeds into our neurons firing, meaning, rewinding the universe and replaying won't result in the same decisions.
I agree but I think you’re overthinking it a bit. Usually when people talk about free will there’s an implication of a “spirit”, or something similar, that is the source of your thoughts. That’s the “you”.
I guess it depends on how you define it but I would say physics is the author of your thoughts. Physics is what’s making the decisions. Physics is the reason neurons fire.
Well, I can't debate people who believe in the spiritual realm, they can believe in free will and there is not much debate to be had.
But for anyone else, I still don't see how the concept of free will even makes sense. It is either determined, or random. What other options are there?
The dedinition should distinguish free will vs free agency.
We have free agency to do what is possible for us, like ultimately committing suicide to restrict that freedom, but we dont have the freedom to choose how we choose because this will never be fully transparent to us, even though we can approximate it with mindfullness.
So, to answer OPs question how the world would look like with "free will", i imagine a world without all those cognitive biases like this entire tribalistic political bullshit we are seeing around the world with identity infested right (and lesser, left) wing movements as a reaction to ever more complex global problems, so quite a contrast.
I think Free Will basically means that nobody else can force us to will, to desire, to like what we like.
A non-free-will would be something where somebody else controls my mind. Like you could imagine hearing thoughts in your head which you think are thought by someone else, like in schizophrenia I guess.
You can force me to do something but you cannot force me to will/want/like anything.
The core of the flaw in your proposition is the premise of making the determination based on external observation.
The actual question is this: do I have free will or not? Life presents us with choices. To paraphrase the prince of Denmark, 'Do I decide to do x or !x? That is the question'.
Related question is does I (distinct from Reality) even have a real existence?
In the 2 slit experiment, as long as the future state of the system is undecidable, we see light behave as waves. When the future of the system is constrained (by measure, which is a 'means of determination') does light behave like a particle.
> As far as I can tell, our current world is indistinguishable from a world with free will
As far as I can tell, everything in our world is governed by the laws of physics, and free will is an illusion. We "make choices", but only because physics moves our brain from one state to the next, and your "choices" only have one option - the one that follows physics.
(this assumes there's no true randomness in the universe, as it requires a source of true randomness, so infinite regress)
But even with true randomness, it would not suddenly turn will into free will. It would turn it into chaotic/unpredictable will maybe, governed by random events, not free.
To us free will feels real because that’s how our neurons fire. We can refuse because there are patterns of neuron activation that lead to the physical act of refusal.
If you don't have free will, you shouldn't be able to resist my suggestion. That's what it means to lack free will - to obey suggestion. If free will existed in this form, then your claim that free will doesn't exist will be wrong. If you want to say that some forms of free will exist and some don't, feel free to elaborate which do and which don't. If you want to say that compatibilistic free will exist and libertarian doesn't, that's completely reasonable, but "free will exists" is the accurate description of this situation.
Will is affecting, bringing about, one's intent. Intentions are based on thought. Thought is engendered in the mind. A weak mind is susceptible to suggestions. Suggestibility is indicative of an inability to resist 'external' (not necessarily in the physical sense) influences.
The question of free will is meaningful as a dual of the proposition of determinism. I suggest to you :) that you lack clarity of thought and need to work on that.
No, your response is not scientific. The default, rational assumption is that the brain works through normal physical processes.
In order for free will to exist there would need to be some force outside of normal physics that influences the physical world.
No evidence for this force of nature exists. And, at a high level, this is no different from other quackery like psychics, witchcraft and other similar nonsense where people insist that their minds can influence the physical world beyond normal physics.
I think your mistake is to take “free will” to be something that exists or could exist (ie: in the same realm as physical forces). Which is, of course, just as “outside of physics” as the concept of a spirit or God.
“Free will” is a cultural-linguistic construct. How could it be anything else? The very concepts of discrete individuals, let alone agency, is effectively arbitrary as far as physical forces are concerned.
The “things” that free will concern are already many, many layers of abstractions (and cultural-linguistic construction) away from the individual deterministic interactions of what we currently understand to be physics.
And, like all abstractions, these are leaky and imprecise. So trying to model or analyse their behavior in terms of deterministic physical interactions has always seemed misguided to me.
Let's also think about Quantum Mechanics. It says the world is non-deterministic. A photon basically has FREE WILL to decide which slit it goes through in the double-slit experiment.
The Laws of Physics cannot dictate whether Schrodinger's cat dies because an atomic reaction happens, only that there is a specific probability for that happening.
So if the world is not deterministic neither are human brains. Physics cannot dictate what the brains think, it can only dictate what the probabilities for some neuron pathways opening or closing are.
I don't know the whole of the compatibilism arguments but they're just defining a moral framework within which you're still accountable. It doesn't say that free will is real.
It can all be broken down as follows:
Rewind time by a certain amount where the entire universe is exactly as it was at that instant. Start the replay. Do you make all the exact same choices, is the universe exactly the same when we get back to the present time?
If the answer is yes, then most people will accept that rejects the most common understanding of free will.
If the answer is no, then by what mechanism were different choices made? How did the neurons in your brain fire differently to make different choices? It must be random. And if it is just random, then that, to me (and many others) also rejects the most common understanding of free will.
But, that doesn't reject the idea of accountability within this system, because accountability is the feedback that directs the neurons to fire in a certain manner to make choices that soiciety prefers. If there was no accountability, no punishment for behaviour that was harmful to other individuals, it would not have good outcomes. So the system creates accountability. It must, because that accountability is part of the physical process by which choices are made.
It's not an illusion any more than Vegas odds are an illusion. Free will is the (correct) perception by an agent that its actions can't be predicted by other agents. My guess is that there will never be an agent that can predict my moment-by-moment thoughts and actions, so I'll always have free will.
Free will is the idea that there is a "you" and you are the author of your actions, or at least you can significantly influence your actions.
Of course, your actions are authored by the neurons in your brain but most people speak as if there is more to it than that. As if there is a "you" that exists outside the brain.
If you can imagine, say, being imprisoned in a 10x10 cell for the rest of your life, and how that would affect your own internal sense of "free will", I think you'll realize it's not arbitrary.
One of the debates around free will centers on an idea that free will means actions must be physically random. So, I think people understand that probability and randomness are really important pieces to understanding free will.
The missing link is understanding that probability is a state of mind. It doesn't matter that the physics is deterministic. (Deterministic physics is indeed also responsible for my current unique perception of my consciousness, so deterministic physics can do a whole heckuva lot.)
So, yes, my moment-by-moment decisions in the sea of the universe's physics and other conscious agents are determined by physics, but to all possible computational agents my moment-by-moment decisions and their affect on reality are weighted random.
I think it's just most people don't really understand physics. If they get the concept of emergent effects, complexity and how free will vs no free will are basically indistinguishable to the humans, I doubt they would still agree with the same conclusion.
Most people consider free will as an ability to make one's own decisions not coerced by someone else. It doesn't conflict with laws of physics. And even if they believed otherwise, it wouldn't mean much, as it won't be the first wrong belief about reality.
Normal physical processes are not deterministic. You don't need to speculate on a source of non-determinism, it's right there in the substrate. Penrose's entire argument is based on a fallacy (you need quantum effects for a system to be non-deterministic) and we've known this since the double-pendulum.
It's hard to buy that their proposed stories are the simplest explanation for these few measurements. Much more boring phenomena can influence QY. e.g. simply occluding fluorophores from the bulk solvent can have a huge influence on QY and spectra. (I used to design biological fluorescent reporter reagents...)