Nondeterminism doesn't necessarily imply free will?

So some philosophers and physicists have argued that Quantum Mechanics disproves a deterministic universe (although the debate is by no means settled on this issue), yet at the same time the outcome of the wave function when it collapses is entirely random, nobody actually “chooses” the outcome, an electron is either spin up or spin down in whatever axes it’s on. It’s a 50/50 chance and the outcome is completely random. This might show that determinism is false but it doesn’t imply free will and some have argued that perhaps our traditional notions of free will and determinism aren’t correct, that maybe out whole idea about them is somehow logically flawed. What would this imply for the Christian faith? Can the randomness of quantum mechanics be reconciled with free will?

I think we ought to define what a “free will” is before we try to determine it’s comparability (or not) with QM.


I suppose free will is our general “feeling” of not being compelled when we do things such as choosing to eat one sort of food over another. Is this feeling from somewhere else? Or is this feeling a product of the laws of nature/geometry?

I think it’s accepted that at the quantum level it’s random but at the macro level it’s not.

If you believe the laws of nature are consistent, which pretty much every physicist and a lot of philosophers accept as a basic assumption/axiom, then Quantum Mechanics must have some sort of correspondence with what we observe in the macro world. Maybe that will be explained in the hypothetical grand unified theory.

If you believe in God, his plan and eternal salvation, the role of physics and/or philosophy vs free will do not matter.

‘Randomness’ is an extraordinarily difficult concept to describe (let alone prove!) in any real system. Are you certain that quantum effects are ‘random’? And if so, what does that really mean? “Unpredictable”? (That’s not ‘random’.) “Unquantifiable”? (Again… not random.) Something else?

The fact that something has a known number of outcomes – or even that the frequency of these outcomes is relatively equally distributed – is not the definition of “random”, no?

Talking about randomness is off topic. The topic involves nondeterminism which is not the same as randomness. Nondeterminism means you can’t determine something or that its cause cannot be determined. If something has a cause which cannot be determined it does not mean it is random. There is a further difference if you consider what is meant by a random number generator. The number generated is generated in a deterministic way, but the numbers as they pop up meet the requirements for being random.
In any event, randomness and nondeterminism are two different concepts.

I doubt that the activity of quarks should have any relationship whatsoever to the moral activity and choices of man.

One of the problems with free will is that it doesn’t seem to work whether reality is deterministic or whether it’s nondeterministic.

It would seem that our actions/choices are either caused by some preexisting conditions, or they’re random, and neither of these two options are consistent with free will. But perhaps we’re looking at free will incorrectly. Perhaps free will isn’t just the inevitable result of an underlying cause, nor simply a capricious random effect. Perhaps instead, the will acts as a mediator between cause and effect, such that it evaluates and intercedes between the two. Perhaps it has the ability to introduce a secondary cause to the process, a cause that isn’t purely deterministic, but adds an independent element of assessment and choice to the process.

How such a process would work I can’t say, but it might be food for thought.

Random behavior is one type of nondeterministic behavior. :wink:

(On the other hand, rolling a set of dice isn’t random – it’s just sufficiently difficult to model that we shrug and say “meh… for all intents and purposes, it’s close enough to ‘random’ to consider it as such”!)

Hence my comment. :wink:

If, by that, you mean that “chocolate cake” and “dessert” are two different concepts? Sure. :man_shrugging:

Nevertheless, the point that @YHWH_Christ and @Freddy was discussing was whether randomness at the quantum level demonstrates that the universe is non-deterministic. I think there’s merit in that discussion, but it’s also a difficult one to hang your hat on. I think Freddy’s mistaken when he (seems to be) saying that “quantum level random[ness] but [not] at the macro level” means that we’re deterministic at the macro level. After all, you can model behavior with Markov chains and it ends up “feeling” like a good representation of what’s being modeled. Since the “decision” to move from one state to the other is probabilistic, can you say that it’s deterministic?

However, even if you want to make that claim, you’d have to demonstrate that the underlying mechanism is truly random, or if it just has the appearance of randomness. (And, then again, we get to the $64,000 question: can anything be said to be truly random?)

So, basically, I think that your assertion that randomness is irrelevant is mistaken. However, I think that an appeal to randomness – however apropos – is a dead end.

I think that you could show that “pre-existing conditions” are inputs to the subsequent decisions… but can you show causation ? That seems a higher bar… :thinking:

That doesn’t seem to hold up, either. If it did, I wouldn’t pick chocolate chip cookie dough ice cream 99% of the time, right?

That would still be “free will”, then, right?

The question is…what role does the conscious mind play in the process, and to what degree, and in what manner is our conscious mind an active participant in the process, rather than simply a passive observer. AND…how much control do “we” actually have over our conscious minds? Are these too simply the outcome of mindless deterministic and non-deterministic processes?

Experiments seem to demonstrate that the mind makes a choice before we’re consciously aware of having made that choice. Making it seem as though the conscious mind is merely a passive observer and not an active participant in the process. But I think that this conclusion overlooks the fact that decision making is a process in which the conscious mind clearly seems to play a role.

The brain begins with some form of input, and then electrical signals build within the brain until a certain threshold is reached, and an action is chosen. This process likely involves a series of feedback loops between various conscious and subconscious areas of the brain. So although the brain may actually make a decision before the conscious mind is aware of it, that doesn’t mean that the conscious mind didn’t play a vital role in that decision. It’s just that as with all conscious processes there’s a delay between act and awareness.

The question that’s pertinent to this thread is, is that process from input to decision, completely deterministic? It’s definitely not completely random,…but it could still be non-deterministic. If the mind is sufficiently complex, then the uncertainty principal may dictate that it’s impossible to ascertain the outcome based solely upon the initial conditions. So if the initial conditions don’t dictate the outcome, then what does? Does it ultimately come down to one serendipitous act of random chance…or is there something else that dictates the outcome? And what could that “something else” possibly be?

1 Like

You experience a very different life than I. Neither of these would seem to be the case to me.

The random number generator works deterministically to give numbers that are random.

If it works deterministically, then its results aren’t really random. :wink:

(p.s., “random number generators” really aren’t ‘random’. They typically use a date/time value or some other value as the seed for their computations.)

Conversely, true ‘random’ behavior is nondeterministic, by definition.

1 Like

I can fully understand that experience strongly suggests the existence of free will, but the question is, is the appearance of free will only an illusion? Because it would seem to conflict with what the OP suggests are our only two options…things are either deterministic or they’re random. And neither of these two choices are consistent with free will.

Personally I’m not convinced by the argument that free will is self-evident, but neither am I convinced by arguments that free will is impossible. I just don’t know.

But I would like to point out something that @Gorgias alluded to earlier…our reality actually appears to be probabilistic, which means that it appears to incorporate aspects of both determinism and randomness.

We begin with a set of initial conditions, and those initial conditions should determine the outcome, but… there’s a degree of uncertainty in those initial conditions such that what we’re left with is a set of probable outcomes, not a fixed, deterministic outcome. At a fundamental level, reality doesn’t appear to be completely deterministic, rather it appears to be probabilistic. However, within that set of probable outcomes, the final outcome appears to be random. There’s no way to predict, for example, whether the particle will be spin up or spin down, or whether Schrodinger’s cat will be alive or dead. So the final outcome, although constrained by the initial conditions, ultimately appears to be random.

But that leads to the question of, how does what’s true at the micro scale translate to what’s true at the macro scale? For example, if the initial conditions can constrain the possible outcomes, can the conscious mind also act to constrain the outcome?

In other words, can the conscious mind impart some influence on what would otherwise be a random process?

I don’t know, because I don’t know, what I don’t know.

No. This is not true for hardware random number generators, where random numbers are generated from a physical process, not an algorithm. Francis Galton showed how to generate random numbers using dice and under Newtonian mechanics such outcomes are deterministic.

Umm… yeah. Both hardware and software generators are pseudo-random.

(Trust me: if you came up with a truly random number generator, you could name your price for it – the cryptographic applications alone would net you a fortune!)

I do not, in the least, attribute free will to some sort of quantum mechanics phenomena. I realize you are not claiming that, nor are you saying I do, but the thread seems to imply that’s the only option, and it is really quack science and quick philosophy to even discuss it.

This whole idea that free will is an illusion is another claim that has zero evidence. And even if we accept a purely materialistic, deterministic world, why? Why would we have this illusion? What evolutionary purpose does it serve? And where are the genetic disorders where it us lacking?

It also begs the question if how physical inputs into a man’s senses can be completely responsible for some if the achievements if maniund.?

That’s not where I’m coming from. From my perspective, if one can demonstrate that the only possible alternative to “free will” is a non-deterministic process, then we’ve already defeated the objection that determinism is true.

From there, we can continue the discussion of free will, without the objection of “determinism! it’s gotta be determinism!” continuing to be raised…

1 Like
DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit