I suppose we could stipulate that Ned has enough information about his immediate environment to make an accurate prediction about how he will act. It doesn't really concern us whether this sort of information can, as a matter of practicality, be acquired; the concern is whether in principle, if this information were acquired, could Ned act in opposition to it. And the answer to that seems to be yes. — NotAristotle
I suppose we could stipulate that Ned has enough information about his immediate environment to make an accurate prediction about how he will act. It doesn't really concern us whether this sort of information can, as a matter of practicality, be acquired; the concern is whether in principle, if this information were acquired, could Ned act in opposition to it. And the answer to that seems to be yes. — NotAristotle
1. With sufficient information about Ned’s internal states and sufficient information about the surrounding environment, Ned’s immediate actions could be predicted.
2. There is sufficient information about Ned’s internal states and sufficient information about the surrounding environment.
3. Therefore, Ned’s immediate actions can be predicted. — NotAristotle
the concern is whether in principle, if this information were acquired, could Ned act in opposition to it. And the answer to that seems to be yes. — NotAristotle
However, there seems to be no reason Ned could choose not to follow the prediction... — NotAristotle
In the original scenario as I have described it, Ned reads the printout, but he only reads a part of it. And, importantly, he does not read a part of it where he is reading the printout -- that would be self-referentially problematic. Because there is no self-referentially in the parts of the printout that Ned does read, there is nothing necessarily theoretically vicious about Ned reading some parts of the printout. — NotAristotle
As formulated, I don't think it proves anything, because it doesn't tell us WHY Ned decided to not go for a walk. Typically, interest zeroes in on the case where Ned makes that choice specifically in order to contradict the machine's prediction. Assuming that to be the case, the thought experiment only demonstrates that, while determinism might still be true, a Laplacian daemon that can predict the future of our universe must be causally isolated from it. That is, the daemon cannot do anything that affects the universe - she can look but not touch.Issue 1: What do you make of this thought experiment? Does it disprove determinism? — NotAristotle
In this case, the computer would need to forecast what occurs as a consequence of Ned reading the printout. This would invariably involve predicting Ned's reaction to the prediction, triggering the problematic self-reference loop I had mentioned. — Pierre-Normand
Additionally, a similar thread has been posted on this forum, I will include it here in case the reader would like to refer to it: https://thephilosophyforum.com/discussion/6478/determinism-vs-predictability/p1 — NotAristotle
It feels intuitively to me that in some, many, most? cases unraveling cause is not possible even in theory. It's not just a case of being ignorant. Part of that feeling is a conviction that sufficiently complex systems, even those that are theoretically "caused," could not be unraveled with the fastest supercomputer operating for the life of the universe. There is a point, isn't there, where "completely outside the scope of human possibility" turns into "not possible even in theory." Seems to me there is. — T Clark
If something is completely unpredictable, does it still make sense to say it is caused. Isn't cause inextricably tied up with prediction? It may be possible to model and predict a coin flip or build a machine that can flip a coin with near perfect uniformity, but how about 1,000 flips using 1,000 random coins flipped by 1,000 random people? — T Clark
If determinism were true, the printout should accurately predict Ned’s actions; however, because it could potentially not predict accurately, determinism must be false. — NotAristotle
The Paradox of Predictability concerns determinism. In particular, it concerns the idea that if determinism is true, then true predictions should be possible about the future state of the world (or people or subsystems therein). — NotAristotle
a universe U is deterministic when, for any arbitrarily chosen time t0, there exists a law-like function fL which maps the initial state of the universe U0 at time t0 in a unique manner onto the state of the universe Ut at any arbitrarily chosen later time t:
Ut = fL(U0) — Determinism and the Paradox of Predictability
The inference from determinism to predictability, though intuitively plausible, needs to be qualified in an important respect. We need to distinguish between two different kinds of predictability. On the one hand, determinism implies external predictability, that is, the possibility for an external observer, not part of the universe, to predict, in principle, all future states of the universe. Yet, on the other hand, embedded predictability as the possibility for an embedded subsystem in the universe to make such predictions, does not obtain in a deterministic universe. — Determinism and the Paradox of Predictability
It feels intuitively to me that in some, many, most? cases unraveling cause is not possible even in theory. It's not just a case of being ignorant. Part of that feeling is a conviction that sufficiently complex systems, even those that are theoretically "caused," could not be unraveled with the fastest supercomputer operating for the life of the universe. There is a point, isn't there, where "completely outside the scope of human possibility" turns into "not possible even in theory." Seems to me there is. — T Clark
it could be that predictability is not achievable under the specified conditions.
The first paper that you cited makes an important point about predictability right in the abstract, by drawing a distinction between external predictability and embedded predictability: — SophistiCat
Determinism, in its most general formulation, does not commit to computability. This, I think, is similar to the point made by ↪T Clark — SophistiCat
Yes. And my claim is that the idea of determinism is meaningless if prediction is not possible, even in theory. — T Clark
I suspect that what people typically mean these days when saying the accept determinism is that they accept it as a corollary of accepting physical causal closure. So I don't see it as a meaningless idea inasmuch as it conveys such a perspective at the very least. — wonderer1
I would think a better objection might be that, in light of the predictive issues, a hypothesis of determinism might not be falsifiable. Does that maybe get more at your objection? — wonderer1
To take a step back, I see the whole issue of determinism as a metaphysical one, not subject to empirical verification or falsification. It's a matter of point of view, not fact. I don't see it as a very useful way of thinking - it's misleading. — T Clark
For that matter, I think the idea of causation can be misleading except in the simplest cases. — T Clark
Yes. And my claim is that the idea of determinism is meaningless if prediction is not possible, even in theory. — T Clark
Perhaps you meant that it is meaningless in the sense that it is of no significance to us whether or not the Universe is deterministic, and I would agree with that. — Janus
I'd be interested in hearing more about what you see as misleading. — wonderer1
I don't see the idea of causation as misleading. — wonderer1
Perhaps you meant that it is meaningless in the sense that it is of no significance to us whether or not the Universe is deterministic, and I would agree with that. — Janus
It's a simple pragmatic judgment. If a claim has no meaningful consequences in the real world, it is 1) metaphysics or 2) meaningless. As a metaphysical position, I don't see it as useful either ontologically or morally. Ontologically, I think it's misleading because it underpins the idea of causation, which I think leads people to look in the wrong places for the genesis of phenomena. Morally, I think it's misleading because it is used to justify a willingness not to hold people responsible for their actions. — T Clark
We've had a few threads here on the forum where I've made the case that the idea of causality is unnecessary and misleading. Admittedly, most people have found my arguments unconvincing. — T Clark
To take a step back, I see the whole issue of determinism as a metaphysical one, not subject to empirical verification or falsification. It's a matter of point of view, not fact. I don't see it as a very useful way of thinking - it's misleading. — T Clark
Did you happen to observe my recent demonstration, here on the forums, of how predictable people can be? — wonderer1
At the same time, I am not convinced that there is one true theory to rule them all at the bottom of creation. Which in turn makes it meaningless to ask whether the world is really deterministic or indeterministic. — SophistiCat
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