Say there is a 50/50 chance of some event occurring. How does that probability factor affect whether or not the universe is deterministic? — Josh Alfred

Determinism is the thesis that the state of the universe at any given time, together with the laws of nature, fixes (determines) the states of the universe at all other times.

Where does the 50/50 probability come from? If you are saying that the state of the universe, together with the laws of nature, fix some event with only 50% probability, then that directly contradicts the deterministic thesis. If you are saying anything other than that, e.g. that it is your subjective assessment of some outcome based on limited information, then it is irrelevant to determinism.

"If you are saying that the state of the universe, together with the laws of nature, fix some event with only 50% probability"

It may fix an event with 50% probability from the perspective of a conscious observer, but still be determined by the universe itself. It's the one refuge for determinism after quantum mechanics. The Aspect experiment ruled out hidden variables, but you may still maintain that whatever happens is determined, just not predictable with any information, hidden or not.

If you find TRUE RANDOMNESS (that exists in quantum mechanics as far as we know) then determinism is done for. Not much luck for free will though if that was going to be your next step. You’re still not choosing if all your actions are determined by a series of random events and determined events

Well, probability is usually introduced to beginners with coins, dice and cards.

Flipping a coin or throwing dice involve force vectors, mass, etc. All of these quantities follow the laws of nature, which means if we know all the details of the initial states then we can actually determine the outcome of a coin flip or a dice throw.

However, this fact isn't taken into consideration, the initial state of the coin or dice being unknown and variable, and so we assume the outcome is random.

Strangely, the experimental probability (actually flipping a coin and throwing a dice) approximates the theoretical probability (a priori estimation)

This means that a deterministic system can lead to probabilistic phenomena.

Doesn't this prove that determinism isn't disproved by probabilistic phenomena?

Now, playing cards. Selecting a card is not like a coin flip or a dice throw. There are no physical laws that can be applied to it like force or mass. Here the person choosing the card is the ''random'' parameter and still experimental probability approximates theoretical probability.

So, experimental and theoritical probabilities match in one situation where the laws of nature are in play (obviously deterministic) and another where the laws of nature are absent (a person is the random element). We can draw two conclusions from this:

1. Determinism can lead to probabilistic phenomena

2. A person's involvement (free will if true) can't be differentiated sufficiently from 1

What do you think?

Determinism of intelligent agents is a fallacy. We experience many so called deterministic events involving non-thinking substance but thinking, animate things are not affected by causality in the same way.

Suicide is a good example of freewill. We have evolutionary programming to protect our own lives, yet in extreme situations people can override this programming, this is freewill. Any conscious made against inclination is also usually a representation of freewill.

Yes we are influenced by causality and determinism, no we are not helpless victims to these forces.

It may fix an event with 50% probability from the perspective of a conscious observer, but still be determined by the universe itself. — Karl

No, I specifically said that it is fixed by "the state of the universe, together with the laws of nature" and contrasted that with what you are saying. The former would contradict determinism, the latter would not.

Ok. Then I misinterpreted what you originally wrote.

It may fix an event with 50% probability from the perspective of a conscious observer, but still be determined by the universe itself. It's the one refuge for determinism after quantum mechanics. The Aspect experiment ruled out hidden variables, but you may still maintain that whatever happens is determined, just not predictable with any information, hidden or not. — Karl

Not quite. QM without collapse is a fully deterministic theory. A coin might not provide the probabilities you seek, but a quantum bit generator would. Then you would have complete objective determinism with subjective indeterminism.

Of course collapse doesn't happen in Copenhagen interpretation either, so it is compatible with determinism. At least some physicists think so.

I doubt I fully understood what you just wrote. "QM without collapse." - Are you referring to the many worlds interpretation?

I don't think that Quantum mechanics is helpful or useful in this sort of discussion, because of it's many conflicting interpretations that parallel the philosophical disputes that already existed in classical mechanics in relation to probability, time and counterfactual reasoning.

I doubt I fully understood what you just wrote. "QM without collapse." - Are you referring to the many worlds interpretation? — Karl

Realist no-collapse theories are Many Worlds theories and are objectively deterministic but subjectively indeterministic.

Copenhagen is an anti-realist theory, which is compatible with single-history determinism, in which case it is often referred to as super-determinism.

It is interesting to note that probability theory was epistemic from its inception. It only became part of reality with the advent of evolution. Then Born took that idea and applied it to everything else.

I like Many Worlds because it explains what probabilities are, while Copenhagen makes no effort to. Super-determinists regard probabilities as an artefact of a defective theory, while Many Worlds explains them as a density of histories.

Super determinism was what I was referring to in my original post.

Yes, you can preserve determinism with the many worlds interpretation, but although I respect that you have a very different view, the reason why I didn't even think of it when I wrote my original post, is that I don't take it seriously.

Anyway, doesn't the semantic under-determination of the word "determinism" render the question meaningless?

Consider the following circular definition, which nevertheless has intuitive meaning.

Determinism is the thesis that the state of the universe at any given time, together with the laws of nature, fixes (determines) the states of the universe at all other times. — SophistiCat

But this definition is also fulfilled by taking determinism to refer only to the fixing of an arbitrary finite number of states. And no amount of protest against this non-standard interpretation of "determinism" is able to eliminate it.

So it isn't clear in my mind, as to how the original question can be sufficiently represented.

Consider the following circular definition, which nevertheless has intuitive meaning. — sime

I don't think the definition is circular, but if you seek a re-formulation, you could express the same idea by stating that the universe is a static 4-D block.

Under this view, probabilities are what they were at their inception - epistemic, and play no role in physical reality.

Probability theory is just a tool.

What actually happens, happens with 100% probability (or with 1.0 probability).

Is the World deterministic or not is just a metaphysical question.

Consider the following circular definition, which nevertheless has intuitive meaning. — sime

Determinism is the thesis that the state of the universe at any given time, together with the laws of nature, fixes (determines) the states of the universe at all other times. — SophistiCat

It's not circular, just because the word 'determines' occurs in the definition. You can easily rewrite the definition without that word.

But this definition is also fulfilled by taking determinism to refer only to the fixing of an arbitrary finite number of states. — sime

No, some is not the same as all, so your definition does not fit the above. I've never seen determinism used in this sense, so I don't see why this should be taken seriously.

Say there is a 50/50 chance of some event occurring. How does that probability factor affect whether or not the universe is deterministic? — Josh Alfred

What event has a 50/50 chance that is purely random? If you flip a coin, all the parameters of flipping the coin determine the outcome. Just because you as a human cannot perceive all the reasons for the outcome, doesn't mean its 50/50

The only place where there's a 50/50 chance is down at a quantum level, but there are no scientific theories that determine that the quantum level has any impact on large scale events being randomized. The randomness at a quantum level has an almost infinite non-effect on anything at larger scales. As soon as it scales up, the outcomes become determined by preceding events. The quantum randomness seems to be related to how matter and energy become defined, not outcomes of events in time.

So there is nothing that can really be defined as a 50/50 chance and therefore there aren't any randomness to affect the nature of determinism.

However, we run into interesting questions if we start using things like the ANU quantum generator
http://qrng.anu.edu.au/index.php
If you choose based on the outcome of quantum generation, you are essentially deciding based on pure randomness. But then again, the choice to do so is deterministic, the choice on how to do something, to do something and so on is still deterministic. And further on, the numbers that come up are defined by a computer choosing the randomness, so the determinism is still in place. The computer chooses a set of numbers, why not double that set? Use half a set? So it becomes, even at this level, hard to determine if it's dislocated from determinism or if it's an illusion of being free of determinism.

But it's intriguing to roll a quantum dice for the choices you make during a day. If you use that dice for all the choices during a day, you are essentially still following determinism in which two choices you have to choose by, but hacking determinism in which outcome that happens.

But it's still not hacking determinism into splitting the universal determinism, even though it's the grandest illusion of bypassing it for us humans.

I'd like to add this thought,

That when there is a probability of something happening its as if the laws of determinism have been bypassed. Considering that probabilities are not 100% certain at all time, the universe must somehow than be non-deterministic. Meaning, whenever there is a probability involved, there is a proof that the universe is not behaving deterministically. What do you think about this?

That when there is a probability of something happening its as if the laws of determinism have been bypassed. Considering that probabilities are not 100% certain at all time, the universe must somehow than be non-deterministic. Meaning, whenever there is a probability involved, there is a proof that the universe is not behaving deterministically. What do you think about this? — Josh Alfred

I think you are viewing determinism through the eyes of a human, meaning that you can't perceive the small causes and effects that in the end define the path of an event. Say we have a large object that's balancing and could fall to either side. We pinpoint a probability of it falling to the left or the right to be 50/50. But this is an illusion. If we would count all details that decide which side it would fall, we would know 100% which side it's going to fall to. Meaning you count in not only it's balanced weight, but changes to the wind a few kilometers away, the movement of earth's core, magnetic field, atmospheric changes of pressure, the side the sun shines on the object propelling it by heat energy and millions, billions of more reasons for it to fall to a specific side. The reason it falls to the left at that very time is very much the result of determinism deciding at 100% probability.

The difference here is that humanity's measurements of probability are limited, while the determinism of the entire universe affecting the object is solid. We just can't measure things to such an extreme point that we can predict it and for our existence, it's such an infinite calculation that it's easier to pinpoint a probability of 50 / 50 than trying to accurately calculate it.