A: I’m not sure I really understand this question. First, what does it mean for randomness to be a matter of perspective? How could it be? It’s empirically observable, and probably not dependent on inertial reference frame or some such. I mean, it could be a matter of perspective in the sense that it could only seem random because we don’t know enough details about what caused it, but that wouldn’t mean we wouldn’t understand the concept. Or maybe you didn’t actually mean as opposed to understanding the concept of randomness, but understanding the phenomena we assume are random. However, phenomena being possibly understandable with enough information is not mutually exclusive with randomness being a matter of perspective as you imply; in fact, it’s the opposite: randomness would be a matter of perspective if we think it’s random but would change our minds if we had more information (in which case the phenomena are understandable with enough information). So, this question is a jumble of mismatched and/or nonsensical ideas and/or wording, so you should probably work on developing your mind to think more logically and clearly.
Anyway, assuming your question is really “is randomness a matter of perspective, in that random phenomena can actually be understood with enough information?”, the answer is (a) we don’t know for sure, and (b) it depends on the particular phenomenon. For example, if you roll a die, that seems random, but if you knew the exact starting conditions (height, rotational velocity on all three axes, speed and direction, and rotational angle on all three axes), and compute the trajectory including factors such as the force of gravity on Earth, wind resistance (which depends on elevation above sea level , temperature and humidity), angle of the surface it’s landing on, perhaps the friction of the surface it’s landing on, the size and shape the die, and any constant source of wind in the room, you should be able to determine exactly how it will land.
If it lands close enough to exactly balanced on an edge, though, it still may not be predictable, unless you knew the positions of all the relevant molecules, etc. somehow and had a computer massive enough to calculate al their interactions, because it would be such a delicate balance that the smallest influences could push it over the edge one way or the other. And even then, if quantum amplification (which is when normally nanoscopic quantum events have macroscopic effects) could come into play through the butterfly effect, it’s not possible to predict it even in theory, because quantum mechanics isn’t a deterministic theory; it includes randomness/probability as a fundamental element. Similarly, we can’t predict any quantum experiment that makes use of quantum-random events, even in theory (i.e., even if we had all the information in the universe).
However, we could speculate that if we had a better physical theory, it would be deterministic and we could predict anything in theory. But that remains speculation, because we don’t know for sure if reality is actually deterministic or if there’s an element of “absolute randomness.”
I think most scientists believe the randomness of quantum mechanics is “absolutely random” (i.e., not possibly understandable or predictable, even in theory/with all the information in the universe), and they don’t just assume this for no reason: the nature of how randomness expresses itself in the theory and in various experiments and thought experiments seems to strongly suggest that there’s no mechanical causality behind it.
There are deterministic theories or interpretations of quantum mechanics, but none of them make any new predictions as far as I know (i.e., they still can’t actually predict quantum-random events), so they can’t be verified, or if they do make new predictions, they have yet to be verified or disproven due to technological/practical limitations. So, they remain speculation.
Also, some people believe that the wavefunctions that determine the probability distributions of quantum events, or something related to that, are the only real thing, and those are exactly calculable, so they think the universe is deterministic. But I don’t think this makes sense. Those equations only determine the probabilities of things, so they involve an element of randomness by definition, and the outcomes of the random events we see when the wavefunctions “collapse” are real; they’re empirically observable—even more so than the wavefunctions themselves, which are abstract and unobservable. And they’re of course nondeterministic, or at least unpredictable so if they’re supposed to be deterministic it’s not proven.
There is another sense in which the universe may be deterministic, or may be considered deterministic depending on how you look at it at least. Most physicists think the interpretation of quantum mechanics that’s simplest and most coherent and therefore likely true is the many-worlds interpretation. Under this interpretation, every possible outcome of every quantum event branches off into a totally separate world which continues on with that particular outcome as part of its causal timeline.
It still doesn’t mean that you can predict quantum events in any one world, because observing the event is the only way to know which of the possible worlds you find yourself in, and before that split, every possible outcome is actually part of your future, or at least they’re all equally probable to be your future, depending on how you look at it. But if many-worlds theory is true, it would mean the universe as a whole is deterministic, if you define “universe” as the entire collection of all possible/manifested worlds. So, that’s why I say it’s deterministic or not depending on how you look at it.
Many-words interpretation is not verifiable because the various worlds do not interact with each other according to the theory, so there’s no way we can test whether there are any other worlds. And one objection to many-worlds theory is that producing a plethora of whole new worlds/timelines for each miniscule quantum event is an incommensurate action, as in something that small shouldn’t produce something that huge.
It may also be considered in violation of Occam’s razor (which is the very sensible idea that the scientific theory that proposes the smallest number of entities to explain/predict the observed data is the most likely correct), because an infinity of alternate worlds created every nanosecond is a lot of extra entities. I’m not sure if it really violates Occam’s razor or not, I suppose because those extra worlds/entities aren’t empirically observable/don’t affect us in any way, which means they only “exist” in a weaker sense of the concept of “exists.” (See my explanation of why it only makes sense to say that things that can possibly affect us somehow “exist” in my essay On the Meaning of "Exists".)
Another argument for the universe being deterministic is that, according to general theory of relativity (which is incontrovertibly correct, based on countless observations of many different kinds to extreme precision, like quantum mechanics is), there’s no single universally reconcilable “now”: there are situations in which when something’s “now” is depends entirely on your reference frame. Most of these potential ambiguities are reconcilable under a particular theory, but even under that theory, there still remain some situations in which “now” can’t be universal.
And that seems to imply that the past, present and future actually exist still/already, such as in a “block universe,” which is the idea that all 3-dimensional states of the universe over time exist as if they’re stacked up in a four-dimensional block, where the fourth dimension is what we experience as time, sort of like how all the 2-dimensional images on a VHS tape are timelessly placed in linear succession on the magnetic strip.
Under block universe, the passage of time is merely an illusion created by our brains because it helps us navigate our environment to do things conducive to propagating our DNA and making our respective species more evolutionarily fit. You may wonder why the process of evolution would even be a thing if there’s no objective passage of time, but it still makes sense: the successive 3-dimensional slices of the block universe are still related to each other in accordance to the laws of physics; otherwise the laws of physics as we know them would be completely different or wouldn’t exist at all, and evolution is obviously something that arises under the laws of physics, or in other words, the contents of “future” (i.e., higher or lower or whatever in the 4th dimension) 3-dimensional slices are still logically dependent on the contents of “past” slices, if not in an actually causal sense. (Or it could actually still be causal, if you define causality merely as a set of particular relationships that necessarily exist between past and future states, or at least between what appear to us as past and future states.)
And, of course, if the future already exists, then everything that ever happened had to happen that way from the beginning of time, which means the universe is deterministic, which means there’s no true randomness. Or does it? Block universe still wouldn’t mean we can predict quantum-random events given all the information, because the quantum-random events in a block universe could still be meaningless, or totally not understandable, because even though they’re all “pre-defined” in the block universe, there’s not necessarily any logical reason they “were” (or “are”) defined to “happen” the way they “do” as opposed to any other way. That seems counterintuitive, of course, but it’s no more counterintuitive than absolute, meaningless randomness existing under quantum mechanics in the universe as we already know it with the assumption that time is real.
You could of course predict quantum-random events if you had access to information from the future, but we probably couldn’t access that, and if we could, it would create a causal paradox because our accessing it and the knowledge we get therefrom would necessarily be a part of the timeline that determines the future. Except it’s conceivable that such a causal loop could exist in the block universe in a consistent, “stable”/static way, though it’s not clear why it likely would, because the entire state of the loop itself couldn’t be logically necessitated by by any earlier or later time-slices like most of the universe would be (besides quantum randomness), because for it to be logically determined by the past, the past frames of the loop would have to “know” the future frames “before” they even “happen” in order to “happen” in a way that’s compatible with the future frames, and conversely, for it to be logically necessitated by future frames, the later frames of the loop would have to “know” the state of the earlier frames “before” they even “happen” when following the states backward in time. (You could just as well follow backward as follow forward in time when thinking about a block universe, because the laws of physics themselves are symmetrical in time. (Entropy isn’t symmetrical in time, but entropy is an emergent property of the more fundamental laws.)) And it’s also not clear why those loops would exist because, as per the above reasoning, there are infinite possibilities for what loops could exist, with no particular logic to select which ones happen or when or how often they do.)
I wrote a lot more about how randomness in quantum mechanics works, as well as my spiritual takes on the nature of randomness, in this thread (this is link to a copy of it in Google Docs): Christian Umunnakwe.