Does Randomness Actually Exist? Does it matter?

Great Debates
1

Are there things in this universe that, regardless of how well we understand the underlying physical phenomena and starting conditions, cannot be predicted, or are events that we call “random” merely an artifact of our lack of knowledge of the event?

For example, take the most common example of a random event: the outcome of a coin flip. A fairly weighted coin will come up heads 50% of the time, making predicting the outcome with greater than 50% accuracy extremely unlikely over many flips. However, if I had perfect knowledge of the forces acting on the coin (the action of the hand throwing the coin, the speed and direction of the air currents during the flight of the coin), wouldn’t I be able to predict the outcome of the coin toss with 100% accuracy?

Put another way, if I built a perfectly precise flipping machine, and placed it in a vacumn chamber (so that the starting conditions were always the same), wouldn’t the coin always land on the same side?

If this is so, then the randomness of a coin toss is an illusion born from human ignorance. But are there other events that truly are random? Phenomena that can produce different results even starting from the exact same starting conditions?

And does it matter? Obviously, I can’t read the eddies of the air in a room, or perfectly replicate the same force with my thumb over and over again, and therefore a coin flip is random enough to me. And if there are truly random events, do they actually affect macroscopic events, or are they just quantum trivia interesting only to certain physicists?

I think that if there is randomness in the universe, it’s of great philosophical importance (although of arguable practical importance).

Imagine that after decades of mediation in Tibet (or something), you achieve oneness with the universe. In a flash of mystic insight, you suddenly know the state of every object in the universe, as well as gain perfect undertanding of the underlying physical laws behind the universe. You know the position and momentum of every elctron, you know the minds of every sentient being. Could you then say, with perfect accuracy, what’s going to happen next? Or is there still more than one possibility?

If you could then predict future events with perfect accuracy, then we live in a deterministic universe. If you can’t, then there’s still uncertainty and surprises left.

(And where does free will fit into all of this?)

2

As far as we know, the answer to your OP is yes. Localized “hidden variables” were shown not to exist, apparently confirming the suspicion that certain quantum effects are completely random.

This, however, does not discount the possibility that the universe could be “pre-programmed” to act in a certain way, just not in a way we can recognize now (for instance, a hidden variable system that invokes a complicated formula taking into account everything the particles touch, rather than just a preprogrammed constant telling the particle what its value is.)

Similarly, what looks to us like complete randomness in other facets of particle physics, such as atomic decay, could be preprogrammed into the atoms, not necessarily hardcoded, but as a preprogrammed formula taking into account the particle’s history and neighbors. It’s child particles would then be “predestined” to act in a certain way based on that, etc.

In other words, maybe, we don’t know.

3

At this stage, the collapse of an electron’s orbit — and subsequent emission of a particle — seems completely random and arbitary. But as always with science, stay tuned.

4

IMHO, free will is not consistent with either a deterministic universe or a random one. The concept of free will is absurd in the technical sense, i.e., it’s self-contradictory. If the universe is completely ordered, then you don’t make choices, but your actions follow on from initial conditions and an observer with enough information could write your biography before you’re even born. Whereas if the universe is random, then you’re not in control over your actions in any way. You “choose” x because that’s the way the dice came down, but not because you legitimately analyzed the situation.

–Cliffy

5

Quantum randomness is a bad example because there always could be some future discovery which shows that it’s really predictable as long as you’ve got the information and computation power to do so.

The strongest argument I’ve seen for the existence of randomness lies on the back of Gödel’s incompleteness theorem. For those not familiar with it, Kurt Gödel proved in the early 30s that for any logical system with just the right characteristics, there are true statements which are not provable. In particular, the standard axiomatization of natural number arithmetic has those characteristics. Gregory Chaitin, who has studied incompleteness in some detail, believes that these statements can reasonably be said to be true at random.

I’m not sure that I buy it–after all, there are proofs of these statements with different sets of axioms–but I thought I’d bring it up as food for thought.

6

Take a six-digit number made up of the last two digits of the closing values of the Dow, the S&P, and the NASDAQ a week from tomorrow. What would that take for it to NOT be random?

Certainly every investing decision anyone makes would have to be predetermined. Which would pretty much mean we, as humans, would merely have the illusion of free will; our thoughts and actions across the board would be predetermined, and our whole world an automaton. (Maybe this time we’ll crank out the Ultimate Question before the Vogons blow up the place.)

But if free will exists, I posit that randomness exists.

7

RTF, I’m not sure I like the implications of the word “predetermined” in this context. It implies that someone made the determination, that there’s a plan. That’s a separate (but related) issue to whether the world solely follows predictable patterns. The fact that we can predict the future doesn’t mean that it’s been planned.

The more I think of it, the more I agree with Cliffy, regarding free will. A robot following a strict program doesn’t have free will, but neither does Harvey Dent, who defers all of his decisions to a coin flip. But does the fact that human behavior can usually be predicted, perhaps could always be predicted given enough information, mean that it wasn’t chosen freely? After all, even the most staunch proponent of free will would concede that humans are a an unsurprising bunch, much of the time.

I guess what I’m really asking is this: If we could rewind time to 50, 100, or a few billion years ago, and then let it play forward again without changing anything, would history turn out the same way again?

8

I would argue that the noise voltage across an electrical conductor is random. We know the cause. It is the motion of electrical charges in the conductor as a result of the thermal energy in the conductor. The charges are bouncing around in the conductor and at times for a short interval of time more of them will be going in one direction than the other. This results in a momentary voltage across the ends of the conductor. The magnitude, the direction and the duration of the voltage are all unpredictable.

I also think the location on the surface of the earth where the next cosmic ray will strike is random.

I have no idea how this ties in with free will. I guess that’s an exercise for the reader, if any, to do.

9

Microwave photons left over from the Big Bang are continually reaching us from the edge of the observable universe. According to general relativity, these photons by definition could never have interacted with us until this very moment. Since they are thermal (and therefore essentially random), we are continually receiving an unpredictable input that contributes to the thermal motion of the molecules around us. So even on a classical basis the universe can be considered effectively random.

10

harvey dent doesn’t have to flip a coin to justify flipping the coin.

so there is ONE iota of innate knowledge in his skull somewhere.

then again, he’s a fictional character. i’m all for writing mr. dent out of this.

11

I think the OP recognizes that there is unpredictability at the human level. But that doesn’t mean there’s anything random going on. I can’t tell you how an airplane flies because I was Philosophy major, not Mech E. But that doesn’t mean its flight is unexplainable.

–Cliffy

12

Sensitive dependence on initial conditions gives you a doorway out of that paradox. We think of dependency in terms of Prior Condition X plus the passage of time yields Condition Y, but if the only way to obtain Condition Y where Condition Y = “Cliffy does such-and-such” with absolute reliability is to repeat initial conditions exactly (beginning with “OK, time commenced with a Big Bang…”), including every little event and circumstance in the life of Cliffy right down to the state of mind of everyone he runs across and the spin on each and every elementary particle, then we still have dependency but we can no longer distinguish it from what we think of as free will, i.e., “Cliffy did what he did because he is Cliffy, because of the unique and individualized experiences and other characteristics far too distinctively special to his life and self along to ever be explained away as consequences of broad categories or a matrix of cause-and-effect variables that you can isolate and abstract out as a mechanical deus-ex-machina”.

Or, to put it another way, it’s not random, there is a pattern, but not a pattern that contains regular repetitions and can therefore generate specific predictions.

13

I’ve seen that argument before, and I think it fails. You’re simply defining free will as something other than its traditional conception. IMO, you’re making a powerful argument that the absence of free will doesn’t really matter to us that don’t have it. But you’re not saying anything to refute the notion that either our actions are totally controlled by initial conditions (ergo, we have no choice in what we do), or they’re not controlled in any meaningful way at all (ergo, it’s not really us choosing, it’s just the dice falling).

–Cliffy

14

I accept that you disagree, but I continue to disagree with you in turn :slight_smile:

There’s a difference between “You voted Labor because you are a white male between 30 and 45 and grew up in Surrey” and “You voted Labor because <insert entire synopsis of your life here, including all the thoughts passing through your head since you were born>”. People who espouse the existence of free will don’t claim that they act without reason. They have their reasons, and their reasons eventually unpack to a series of events and circumstances even if that’s not how they initially express it —

“Why do you favor legalizing marijuana”

“Because in the absence of a damn good reason, the government has no business telling you what you can or cannot put into your own body. And they don’t have that damn good reason, marijuana is relatively benign physically and mentally. Oh, and ‘pot-hibition’ hasn’t worked anyhow”

“Care to tell me how you arrived at the conclusion that government should not be able to restrict what you put in your body w/o good reason? And how you came to believe that it’s relatively benign? And on what basis you’ve decided that laws against marijuana have been policy failures?”

“Sure. <Insert 54 minute exposition, with elaborations when further questions are asked”

“So, in summary, would it be fair to say that you favor legalizing marijuana because <insert good recap of relevant personal history, including chains of thought & development of personal philosophy, which in turn is described in terms of chains of events experienced and observed>?”

“Yeah, that’s it. Hey, you listen good”
WHEREAS:

“Hey, did you read this article in Peephole Magazine? It says that if you were 10 years old or older when Woodstock occurred and you listened to rock music and watched popular movies in the 70s, you probably favor legalizing marijuana”

“Well, I do, but that’s not why. I make up my own mind, I’m not a puppet of the media or a mere ‘product of my generation’, it’s not like I’m in lockstep accord with my peer group” :mad:
It’s a difference that’s not just a difference of degree; If you include every event in a person’s life, and the entirety of the context in which they lived it, along with the sum total of whatever sequences of events gave them their exact biological makeup, most individualists will agree “You’ve described me”, i.e., they generally aren’t carrying around with them a notion of self that differs from that rather complex sum total of innate characteristics and environment and history. (I suppose the religious folk who believe in a literal soul might differ).

15

With regard to the question posed at the start of the OP:

[quote[Are there things in this universe that, regardless of how well we understand the underlying physical phenomena and starting conditions, cannot be predicted, or are events that we call “random” merely an artifact of our lack of knowledge of the event?[/quote]

It’s an old idea that for some reason keeps popping up in bad fantasy and science fiction (like The Mad Thinker from The Fantastic Four comic book…uhhh…graphic novels).
In practice, we nwever have enough information and arguably can’t. Even if we ignore quantum uncertainty (which, as has been piointed out, is not due to “hidden variables”) and Godel’s Theorem , there is still enough in the simply vastr bulk of information needed to fully predict even simple events. A lot of this gets piled into the bin lebelled “chaos”, but even before the recent obsession with Chaos the idea was batted around. Consider D. Layzer’s artixcle from the Dec. 1975 issue of Scientific American on “The Arrow of Time”. On a microscopic scale, events are reversible, but on a macroscopic scale they aren’t. Perfume will diffuse out of a bottle, but it’s unlikely that it will diffuse back in. Why? side from the miroscopic probability of all the atioms reversing their paths, you have to take into account the way distant events and objects distort motions, scrambling up their “memory” in phase space and effectively preventing such occurrences.

This isn’t even “sensitive dependence upon initial conditions” – it’s “dependence upon all influences” that prevents both time reversal and your perfect prediction of the workings of the universe. Even in the absence of quantum uncertainty, sensitive dependence upon intial conditions due to self-referential and nonlineal processes, or anything that would make you invoke Godel, you still effectively wouldn’t be able to predict the future of anything but relatively simple situations.

16

Assuming we live in a world without free will, then we really have no choice whether we believe in free will or not. Assuming we live in a universe WITH free will, then we should believe that we have free will. Therefore, believing that we have free will is the only logical position.

17

[logician]It is true, because false => X is true, regardless of the truth value of X.[/logician]

18

I have a follow up question. The OP asks if we can predict all events - it seems not. I ask, can we explain all events? That is, given enough time, could we theoretically record enough information about the state of the room to have determined why the coin fell on tails, even if we could not do so in real time?