StillDreaming

You're saying now that a probabilistic system is deterministic, since it has an expected value. However, in an earlier post you agreed probabilistic systems are random, i.e., non-deterministic. They can't be both, of course, so I'm not sure what your think they are.

Anyway, for any system - deterministic or indeterministic - we can construct a probability density function matching the observations, and calculate the corresponding expected vaule for it. So we can easily assign an expected value to an indeterministic system. We can go on testing the hypothesis that the system behaves according to this pdf. However, whether the system actually *is* deterministic or indeterministic is a philisophic question. But for making predictions, it doesn't matter at all.

Normal

Where did I say that?

I accept some probalistic systems are deterministic and some are indeterministic. It is possible for a system to be one or the other.

Yes, a philosophical question that has implications on macroscopic conclusions.

Are you sure? What about predicting which slit an electron will take in the double slit experiment? Or Schrodinger's cat?

StillDreaming

"An indeterministic system will have no expected value." A probabilistic system will have an expected value, so according to this statement it is not indeterministic.


We can use a probabilistic model for a deterministic system, for example because the system is too complex to model it completely, or because we don't know that it is deterministic. However, as soon as we know it is deterministic, and we know the rules, in principle we don't need probabilistic models. I'm not sure if it is correct to call such a system probabilistic (only our model of the system is).


I fail to see them.


You cannot predict individual events in a probabilistic system. Only certain properties of a large number of events. Like expected value, variance etc.
If the system is actually deterministic, and you know the rules, then of course it is possible to predict individual events. But then it is no longer probabilistic.

Jinto

Uh huh... and that contradicts the fact that there IS an expected value... how?

Hint: try actually reading the article, and not stop reading when you see "uncertainty."

You don't have an argument, and I still don't see what the definition of a chair has to do with anything, except as an excuse for not arguing.

Yes. What IS your point?

Jeez... it's like I'm talking to a wall here. :banghead: :banghead: :banghead:

Normal

What exactly is your argument? That you can use the law of large numbers to gain a definite expected value? If so, your argument has been refutted. If you want to change your argument to "An expected value can be approximated", that doesn't answer the question in the OP, so which is it?

You want me to define god when you can't even define a chair. Put 2 and 2 together. You are actually comitting the fallacy of special pleading, if you are interested.

What exactly makes me a wall? That I back up my assertions with sources? That I don't immediately agree with your unsupported assertions? That you have a flimsy understanding of the material and I refuse to teach you your own personal physics lesson? Really, I'm interested in why you are so frustrated.

Normal

The key difference is in a deterministic model individual events follow certain well defined rules. In an indeterministic system those "rules" don't exist.

Jinto

Okay, you just posted a link to a page showing several of the well defined rules obeyed by quantum mechanical systems, and now you're tellling me that quantum mechanical systems don't follow well defined rules.

This is why I feel like I'm talking to a wall.

ComestibleVenom

Hey Normal.

In reference to the following passage:

The 'rules of nature' are the regularities in it's structure. Neither quantum mechanics nor Laplacian determinsim require an explicitly represented 'book of rules'.

Neither theory involves "rules" that "exist". That is not to say one could not add such an element to physical law (for whatever strange reason), just that neither theory actually has such a thing.

Not a key difference, a trivial similarity in the scope of how the theories are used.

ComestibleVenom

Originally posted by ComestibleVenom
I was positing that the systematic temporal relationships are the sort of thing for which the notion of causality is useful. As it turns out, those relationships are of an unexpected nature - but the reduction of causality to quantum mechanics is patently tenable so long as such relationships hold.


Normal,
If we use causality in it's literal classical sense, there is an extent to which it is illusionary and an extent to which it is informative and true. We can explain causality in the sense that can identify (to an extent) the features of nature which have made and continue to make causal descriptions useful or inaccurate.

We know how some stochastic systems may macroscopically approximate determinism under certain conditions. It's not a mystery although our intuitions about stochastic systems are unreliable.
In other words, although the model is different, the principle of reduction is applicable due to the significant and limited isomorpism between the reduced theory(square/macroscopic causality) and the reducing theory(dots/QM). The conceptual error is on your part, and is rooted in what amounts to confusion about what inter-theretic reduction actually involves.

quote:

To which Normal responded:
Intentionality has never been a fundamental sort of thing. It has always had a substructure, and one that simply does not make sense to speak of in terms of intentionality. So no, it is epistemologically implausible and logically useless to say that intentionality logically precedes intentionality. The evolutionary processes and structural regularities producing intentionality are prior to intentionality.


But it's not a solution for the problem it purports to solve. In fact, it's not a solution to anything but is a stopgap for the emotional woes of human existence. Simpler, far more powerful theories exist. Perhaps complex and useless but all-encompassing theories should be abandoned in lieu of simpler, faster evolving and more powerful theories.

Fatasy (ie.illusionary) in some sense it may be, but your contention that it is unparsimonious is not only wrong, it is very near as far from the truth as you can be. I've already countered your contention that causation is unparsimonious - it's not an addition to our ontology but a simplification for our scientific practice.

I am not talking about some esoteric, rare experiments. This is just basic, basic information about the way the field is conducted. It would take you five minutes of googling to verify that quantum mechanical calculations (The ones with which QM systems are systematically predicable!) are sufficiently complex that computers quickly become necessary.

Normal

In reference to the above comment about indeterministic/deterministic systems (I'll avoid Jinto's obvious post hoc wall comment), I was only talking about the subtle difference between indeterministic and deterministic. The rules in deterministic systems are known, there are no rules in indeterministic systems. There is no reason an indeterministic system behaves the way it does, and that is the key difference between the two.

But if you accept quantum mechanics, there is no extent to which it is true, at all.

It involves building up to a model with explainable parts. Atoms arrange themselves to be blue, we know how to reduce a color to atoms. Atoms arrange themselves into different materials, we know how to reduce materials to atoms. Electrons can arrange themselves into apparent casuality, but we don't know how. There is a step missing in the reduction.

But that just takes the question one step back. How can a structure and process be thought of to be unintentional?

But the "complex and useless" theroies can hardly be said to be parsimonious.

It is both!