Determinism

[mem]

Please can I ask for help in understanding what determinism means? I am listening to "Reasonable Doubts" podcast about this subject and I can't get to grips at all. If anyone could just give me a short and simple definition cos I can't get this at all and I'm getting really frustrated with myself.

I know it's not a simple concept but is there just a basic explanation that I can build my understanding on?

Thanks

[Edwardo Piet]

Determinism means that there is only one possible future.

EvF

[WingedFoe]

Everything is determined by past events.

So if a machine were built which knew everything that was happening at that present moment, it would be able to predict everything in the future. That is, assuming the machine knew all laws of physics known and unknown to humankind.

Another way of looking at it is that the entire universe's fate was determined at the moment of the big bang.

[Minimalist]

Another way of looking at it is that the entire universe's fate was determined at the moment of the big bang.

I have to strenuously disagree.


You are not allowing for The Asshole Factor.






Far too many assholes end up in positions of power. No one can predict what they will do.

[Purple Rabbit]

Everything is determined by past events.

So if a machine were built which knew everything that was happening at that present moment, it would be able to predict everything in the future. That is, assuming the machine knew all laws of physics known and unknown to humankind.

Another way of looking at it is that the entire universe's fate was determined at the moment of the big bang.

You're describing Laplace's Demon. But it remains to be seen if it really holds in nature since it assumes that every event has a definite outcome which currently cannot be reconciled with how we understand nature at the quantum level. There are truly (well, for what it's worth, there are no absloute truths in science) random processes in nature, like virtual particle creation and nuclear decay. And since small things can have great consequences the machine you're talking about will need the input but cannot predict it.

And I agree with Minimalist that if a butterfly in China can cause a hurricane in the Carribean than I would not be surprised to learn that an asshole president in the US can rupture the very fabric of the universe.

[mem]

But isn't the idea that everything is already mapped out, well isn't that a bit like "god has planned our lives"? Is determinism a religious stance cos I can't believe in that. It seems crazy to me. Am even more confused now....

[WingedFoe]

But isn't the idea that everything is already mapped out, well isn't that a bit like "god has planned our lives"? Is determinism a religious stance cos I can't believe in that. It seems crazy to me. Am even more confused now....

Nah, determinism doesn't need to invoke any higher power. It says that everything is determined, but does not specify whether it was "planned."

Most scientists (except for, maybe, quantum physicists) presume that determinism is true when they ask "what caused so and so to occur?" A feather falls at an acceleration of 9.81 m/s^2 in a vacuum... what caused it? Gravity. A person feels severely depressed despite having a fairly good life... what caused it? A hormonal imbalance. Determinism would be proven false if an action did not have a cause.

Determinism has held true, so far, in every science at the macroscopic level. At the quantum level it seems to break down, but then you just have probabilities (which are no more kind to the concept of "free will").

[Edwardo Piet]

Determinism is just the idea that the future can only be one way, it can't go any other way, hence why I said it means there is "Only one possible future".

So according to determinism - if it was true then ultimately when it comes down to the details of the matter (whether we will ever know them or can know them or not) even the random quantum mechanics can't be any other way in that exact given moment. At the moment quantum mechanics seems to defy much intuition, common sense and cause and effect and what not. But IF determinism is true then that would mean ultimately it's an illusion and if we somehow broke down the quantum into an even smaller quantum level then it IS ultimately all fixed and "determined" and only at the moment does it look "undetermined" or whatever.

I could be wrong here though because I think I've also heard/read that indeterminism (as opposed to determinism) and the indeterminacy of quantum mechanics are different things. Indeterminism means there are more than one possible futures, it's not determined - whereas indeterminism of quantum mechanics doesn't necessarily imply that at all, in fact gives no implication to it whatsoever - it's just about the random and unpredictable variables of the quantum. This paragraph may be more correct than the above one. But I don't really know - what I wish is to be corrected by someone with more knowledge on this matter than me, while I try and feed in some theoretical thought.

(I DO know the definition of determinism though. It just means that there's only one possible future).

Predeterminism, I believe, as opposed to determinism is the idea that not only the future is determined but it's determined for some some of reason, like destiny, predestination and all that whatnot - that's much closer to being religious bullshit. Determinism itself - alone - isn't.

EvF

[Purple Rabbit]

Determinism is just the idea that the future can only be one way, it can't go any other way, hence why I said it means there is "Only one possible future".

I don't agree. In science determinism generally refers to causal determinism:

Causal determinism is, roughly speaking, the idea that every event is necessitated by antecedent events and conditions together with the laws of nature.

You can observe from this definition that it does not claim "one possible future", only that an event of reality has antcedents that have necessitated it. IOW, this definition looks back into the causal history of events whereas your definition claims something about the future.

So according to determinism - if it was true then ultimately when it comes down to the details of the matter (whether we will ever know them or can know them or not) even the random quantum mechanics can't be any other way in that exact given moment.

Though this is not a result of the stance of causal determinism, since that strictly speaking allows multiple futures as for instance in a multiple parallel universes scenario, we experience just one future and from this fact of life (not from a scientific undergirding) from inductive reasoning follows that only one possible future (whatever it is) is relevant to us. It is fully determined in the sense that it will occur whatever it is.

At the moment quantum mechanics seems to defy much intuition, common sense and cause and effect and what not. But IF determinism is true then that would mean ultimately it's an illusion and if we somehow broke down the quantum into an even smaller quantum level then it IS ultimately all fixed and "determined" and only at the moment does it look "undetermined" or whatever.

As I've stated, the observation from experience that only one future is accessible to us (provided that we live long enough to be around) is not comprimised by the fact that we lack the precise physical description. The final theory to base this on is still lacking. Some descriptions of quantum mechanics, such as Bohmian quantum mechanics, indeed are fully deterministic. However when the so-called "quantum equilibrium” condition is met the Bohmian quantum description is equivalent to standard Copenhagen QM which is not deterministic. So the jury is still out whether we can come up with a fully deterministic description of reality. But this being so does not compromise the fact that one possible future is all that will result when we infer possible states from past experiences.

[Edwardo Piet]

Determinism means the future is determined which means there is only one possible future - if there was more than one possible future then it isn't determined.

I'm talking about philosophical determinism not scientific determinism. As I said, indeterminacy and determinacy in science are perhaps another matter altogether.

Determinism in science I believe refers to the predictability of the future, which has got nothing to do with philosophical determinism which just means that the future is fixed, determined, whether we can predict it at all or not. Philosophical determinism just means there is only one possible future.

Wikipedia: "Determinism is the philosophical view that every event, including human cognition, behavior, decision, and action, is causally determined by the environment. It is, in essence, the view that one's life is predetermined before one is even born. Determinism proposes there is a predetermined unbroken chain of prior occurrences back to the origin of the universe."

If the future is predetermined from the start and layed out, then by definition there can't be any more than one possible future: therefore there is one possible future. Only one possible future=determinism.

You can observe from this definition that it does not claim "one possible future"

It doesn't need to though does it? It just has to imply it. And it absolutely does imply it: If the future is completely predetermined and fixed, then there is only one possibility of what it will be: the way it is fixed, predetermined, to be.

The way I define it as meaning "only one possible future" is how Daniel Dennett defines it by the way...

Determinism, according to Dennett, is the thesis that ''there is at any instant exactly one physically possible future''

EvF