Evidence and all that

[chezlaw]

I'm trying to clear up some of the recuring issues about evidence.

Propositon E.
Suppose two theories T1 and T2 do not make different predictions about the world. Then deciding whether to believe T1 or T2 is nothing to do with evidence.


Consider
T1: some god created the world for some purpose only knowable after we leave this world (die)
T2: no god created this world

By proposition E, deciding between T1 and T2 is not a matter of evidence.

As T1 is one possible conception of god (assuming any conception of god is possible) then evidence cannot rule out the existence of god.

Therefore anyone who believe there is no god doesn't believe this because of the evidence.

chez

I think meta-evidence is involved. There is a lot of evidence that theories that involve supernatural causal mechanisms are unnecessary.

[benjdm]

I know of no religions with God concepts that involve a God who created the universe and then left it alone entirely. For myself, I readily admit such a God is entirely possible and I can't rule it out.

[chezlaw]

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I think meta-evidence is involved. There is a lot of evidence that theories that involve supernatural causal mechanisms are unnecessary.

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what is meta-evidence?

chez

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I think meta-evidence is involved. There is a lot of evidence that theories that involve supernatural causal mechanisms are unnecessary.

[/ QUOTE ]

what is meta-evidence?

[/ QUOTE ]

Evidence for a theory about theories. Is what I'm getting at clear?

[chezlaw]

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I think meta-evidence is involved. There is a lot of evidence that theories that involve supernatural causal mechanisms are unnecessary.

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what is meta-evidence?

[/ QUOTE ]

Evidence for a theory about theories. Is what I'm getting at clear?

[/ QUOTE ]
Not quite. Realising that one or both theories contain something unnecessary is not evidence that the theory is wrong.

Are you getting at Ockhams razor and is this realisation what you mean by meta-evidence?

chez

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Are you getting at Ockhams razor and is this realisation what you mean by meta-evidence?

[/ QUOTE ]

Either a specialization of Ockham's razor or something related to it... I'm still thinking about that part. Whichever, it is a theory (about theories) for which there is evidence. So I reject the claim that the rejection of god is not "based on evidence." It is simply evidenced-based at a higher level.

[peritonlogon]

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I think meta-evidence is involved.

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Certainly is... if by meta-evidence, you mean "beyond evidence" or "after evidence."

[chezlaw]

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I think meta-evidence is involved.

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Certainly is... if by meta-evidence, you mean "beyond evidence" or "after evidence."

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Is that the same as not evidence?

chez?

[maurile]

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I think meta-evidence is involved.

[/ QUOTE ]
That's actually a decent term for the principle underlying Occam's razor.

There's no direct evidence that any particular unfalsifiable theory is wrong. But there is some evidence that where two theories are equal in their explanatory power, the goofier one has a lesser chance of being correct than the simpler one. Not always, but more often than not.

This latter point is supported by observational experience. It is a sort of meta-evidence.

[bobman0330]

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But there is some evidence that where two theories are equal in their explanatory power, the goofier one has a lesser chance of being correct than the simpler one. Not always, but more often than not.

[/ QUOTE ]

It seems to me that a very good argument could be made that theistic theories are less "goofy" in an Occam's Razor sense than their atheistic competitors. At the very least, I think a more rigorous definition of your proposed meta-evidence rule is in order.

In your example T2 and T1 are equally likely. However, T2 has far greater utility and is the smart choice. This is because there are an infinite number of equally likely theories in which any course of action may have an effect, and these theories will balance out to make every course of action identical for purposes of "afterlife" and similar considerations. It is just as likely that God will punish us for being Christian as that he will reward us, for example.

However, this case is irrelevant. Christianity does make different predictions about the world, very different predictions. Those predictions don't bear out. Keep in mind that "implied conditions" are as important here as "actual conditions." In other words, if there had been a world-wide flood and all species of animal had spread from a single point subsequently, there should be evidence of that in today's world. In this case, absence of evidence is indeed evidence of absence.

If you manage to explain all this away, you have to keep in mind that by definition if T1 and T2 make the same prediction there is absolutely no utility in believing T1. T2 has a greater utility, and therefore anyone arguing for T1 is essentially talking about the flying spaghetti monster.

(Theoretically if you have no evidence at all, you make no assumptions at all. You may choose to believe in one thing or another for functional reasons, however - for example if believing in God makes you feel happier)

[chezlaw]

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I think meta-evidence is involved.

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That's actually a decent term for the principle underlying Occam's razor.

There's no direct evidence that any particular unfalsifiable theory is wrong. But there is some evidence that where two theories are equal in their explanatory power, the goofier one has a lesser chance of being correct than the simpler one. Not always, but more often than not.

This latter point is supported by observational experience. It is a sort of meta-evidence.

[/ QUOTE ]
As I pointed out before, this isn't true. there are no cases of examples where two theories don't produce different predictions about the world, yet one has been shown to be false.

or if it is true we realise its true for reasons other than evidence.

chez

[NotReady]

[ QUOTE ]

I know of no religions with God concepts that involve a God who created the universe and then left it alone entirely.


[/ QUOTE ]

Deism. Of late, sometimes known as Sklanskianity.

[chezlaw]

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In your example T2 and T1 are equally likely. However, T2 has far greater utility and is the smart choice. This is because there are an infinite number of equally likely theories in which any course of action may have an effect, and these theories will balance out to make every course of action identical for purposes of "afterlife" and similar considerations. It is just as likely that God will punish us for being Christian as that he will reward us, for example.

[/ QUOTE ]
If two theories don't make different prediction about the world then neither has greater utility.

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However, this case is irrelevant. Christianity does make different predictions about the world, very different predictions. Those predictions don't bear out. Keep in mind that "implied conditions" are as important here as "actual conditions." In other words, if there had been a world-wide flood and all species of animal had spread from a single point subsequently, there should be evidence of that in today's world. In this case, absence of evidence is indeed evidence of absence.

[/ QUOTE ]
Now you switch to Christianity which does make different predictions about the world. Clearly there is lots of evidence about most religons which is why there is a reason to believe them or not.

chez

[Piers]

[ QUOTE ]
I'm trying to clear up some of the recuring issues about evidence.

Propositon E.
Suppose two theories T1 and T2 do not make different predictions about the world. Then deciding whether to believe T1 or T2 is nothing to do with evidence.

[/ QUOTE ]



Consider
T1: It has never been possible to get to Narnia thorough my bedroom wardrobe.
T2: It was possible to get to Nrania through my wardrobe between 2200-2300 GMT on 15 December 2005.

By proposition E, deciding between T1 and T2 is not a matter of evidence.

Therefore anyone who believes that there has never been a link between my bedroom wardrobe and Narnia doesn't believe this because of the evidence.

Note I am fairly sure no one inspected my bedroom wardrobe between 2200-2300 GMT on 15 December 2005.

[chezlaw]

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[ QUOTE ]
I'm trying to clear up some of the recuring issues about evidence.

Propositon E.
Suppose two theories T1 and T2 do not make different predictions about the world. Then deciding whether to believe T1 or T2 is nothing to do with evidence.

[/ QUOTE ]



Consider
T1: It has never been possible to get to Narnia thorough my bedroom wardrobe.
T2: It was possible to get to Nrania through my wardrobe between 2200-2300 GMT on 15 December 2005.

By proposition E, deciding between T1 and T2 is not a matter of evidence.

Therefore anyone who believes that there has never been a link between my bedroom wardrobe and Narnia doesn't believe this because of the evidence.

Note I am fairly sure no one inspected my bedroom wardrobe between 2200-2300 GMT on 15 December 2005.

[/ QUOTE ]
Precisely. (assuming no possibility of evidence of the past in this case).

chez

[BluffTHIS!]

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I know of no religions with God concepts that involve a God who created the universe and then left it alone entirely.


[/ QUOTE ]

Deism. Of late, sometimes known as Sklanskianity.

[/ QUOTE ]

And the beliefs that describe various forms of Deism really make it a philosophy and not a religion. That is, not a religion as other religions are. For if a god created the world and then left it alone, there is no need for doctrine, worship, prayer or rituals of any kind. The things that a religion is known by and which separate it from other religions.

To me, Deism is just a sophisticated form of agnosticism.

[Piers]

I think people tend to use some sort of indution/deduction combination to handle these sorts of situations.

I assumed this was a lead-in to some justification of Christianity. Guess I was wrong.

The simplest theory that makes the same prediction has a greater utility because it is easier to apply. It's basically the "condensed version." Any additional variables in T1 are functionally irrelevant. Those variables may as well not exist, and for practical purposes are not worth considering. All the relevant information is contained within T2 and considering anything beyond that is useless.

There's greater utility in T2 because there is no chance of God "getting in the way."

You have artificially constructed a theorem that explicitly refuses to give "evidence" any weight and then reach the unsurprising conclusion that if anyone holds a belief one way or another they cannot do so based on the evidence.

I.e., the conclusion is tautological from your premise that the answer can only be known after we die.

I believe in science. I believe in evidence. I reject your premise.

[BluffTHIS!]

Nice work. But these "trick questions" are all the rage in this forum.

[David Sklansky]

"Deism. Of late, sometimes known as Sklanskianity."

Deism and Sklanskyanity are very different. Sklanskyanity postualtes a god who will reward and punish.

[chezlaw]

[ QUOTE ]
You have artificially constructed a theorem that explicitly refuses to give "evidence" any weight and then reach the unsurprising conclusion that if anyone holds a belief one way or another they cannot do so based on the evidence.

I.e., the conclusion is tautological from your premise that the answer can only be known after we die.

I believe in science. I believe in evidence. I reject your premise.

[/ QUOTE ]
The argument is in no way an attack on science, nor is there a trick. I would argue that the proposition E is a foundation stone for science.

What do you mean by you reject the premise. All I'm saying is that two theorems that predict the same evidence cannot be decided between on the basis of the evidence. this is true isn't it? so how could you reject it.

chez

[chezlaw]

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Nice work. But these "trick questions" are all the rage in this forum.

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This is not a trick question, why would you think it is? I'm sorry if people mistakenly think its about religon but it isn't. Its about theories that cannot be differentiated between on the basis of evidence.

chez

[maurile]

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I think meta-evidence is involved.

[/ QUOTE ]
That's actually a decent term for the principle underlying Occam's razor.

There's no direct evidence that any particular unfalsifiable theory is wrong. But there is some evidence that where two theories are equal in their explanatory power, the goofier one has a lesser chance of being correct than the simpler one. Not always, but more often than not.

This latter point is supported by observational experience. It is a sort of meta-evidence.

[/ QUOTE ]
As I pointed out before, this isn't true. there are no cases of examples where two theories don't produce different predictions about the world, yet one has been shown to be false.

[/ QUOTE ]
I wasn't clear. By "explanatory power" I mean that they explain things we already know.

I don't mean that the two theories make all the same predictions. For one to be false and the other to be true, obviously they have to make different predictions.

My assertion is that when two theories have the same explanatory power, the simpler one tends to make better predictions. Usually, but not always.

[chezlaw]

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I assumed this was a lead-in to some justification of Christianity. Guess I was wrong.

The simplest theory that makes the same prediction has a greater utility because it is easier to apply. It's basically the "condensed version." Any additional variables in T1 are functionally irrelevant. Those variables may as well not exist, and for practical purposes are not worth considering. All the relevant information is contained within T2 and considering anything beyond that is useless.

There's greater utility in T2 because there is no chance of God "getting in the way."

[/ QUOTE ]
How could the theories have greater utility or be easier to apply than each other if they don't say anything different about the world.

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Those variables may as well not exist, and for practical purposes are not worth considering.

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I couldn't agree more.

chez

[chezlaw]

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I think people tend to use some sort of indution/deduction combination to handle these sorts of situations.

[/ QUOTE ]
and I'm showing that either they don't, or its not on the basis of evidence.

chez

[chezlaw]

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I don't mean that the two theories make all the same predictions. For one to be false and the other to be true, obviously they have to make different predictions.

[/ QUOTE ]
That's exactly what I'm saying as well. So if two theories don't make different predictions then they cannot be decided between on the basis of evidence.

chez

[maurile]

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So if two theories don't make different predictions then they cannot be decided between on the basis of evidence.

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That is where meta-evidence comes in. /images/graemlins/wink.gif

I guess it depends on why the two theories make the same predictions. If it's because the theories are identical, then one is as good as the other.

But if they are not identical, it's just that they differ only with respect to statements that are not testable, then one can still be right and the other wrong -- although it is impossible for us to determine empirically which (if either)is right and which is wrong.

In that case, I think the meta-evidentiary principle is relevant.

[chezlaw]

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So if two theories don't make different predictions then they cannot be decided between on the basis of evidence.

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That is where meta-evidence comes in. /images/graemlins/wink.gif

I guess it depends on why the two theories make the same predictions. If it's because the theories are identical, then one is as good as the other.

But if they are not identical, it's just that they differ only with respect to statements that are not testable, then one can still be right and the other wrong -- although it is impossible for us to determine empirically which (if either)is right and which is wrong.

In that case, I think the meta-evidentiary principle is relevant.

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but no-one ever answers the meta-evidence questions. There are no cases where one of two theories undecidable by normal evidence have been shown to be true, so if you apply meta-evidence you have no normal evidence that the meta-evidence approach is valid.

Hence meta-evidence is a fancy word for something that is not based on evidence.

chez

[maurile]

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There are no cases where one of two theories undecidable by normal evidence have been shown to be true, so if you apply meta-evidence you have no normal evidence that the meta-evidence approach is valid.

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I don't know what you mean by "normal" evidence, but there have been lots of examples of situations where competing theories existed, no experiments had been done to figure out which (if either) was right, and then later somebody came up with an experiment.

The general rule in those situations is that the simpler theory turns out to be the one that is correct. From that we can infer that, in general, simpler theories do better than more complicated theories.

This is not coincidence, by the way. The reason that more complicated theories often fare worse is that the traditional way of making a theory more complicated is to add more stuff onto it. There are more ways to add incorrect stuff than to add correct stuff -- so the more you add, the more likely you are to get some of it wrong.

This is why "the earth travels around the sun" is more likely to be correct than "the earth travels around the sun because it is being pushed by invisible angels." Whenever you add extra stuff on, you are increasing your exposure to potential error.

[ QUOTE ]
That is where meta-evidence comes in. /images/graemlins/wink.gif

I guess it depends on why the two theories make the same predictions. If it's because the theories are identical, then one is as good as the other.

But if they are not identical, it's just that they differ only with respect to statements that are not testable, then one can still be right and the other wrong -- although it is impossible for us to determine empirically which (if either)is right and which is wrong.

In that case, I think the meta-evidentiary principle is relevant.

[/ QUOTE ]

but no-one ever answers the meta-evidence questions. There are no cases where one of two theories undecidable by normal evidence have been shown to be true, so if you apply meta-evidence you have no normal evidence that the meta-evidence approach is valid.

Hence meta-evidence is a fancy word for something that is not based on evidence.

[/ QUOTE ]

I don't think this is correct, if I understand what you are claiming. One is using meta-evidence as support for a meta-theory about which of the two indistinguishable theories is likely to be correct. That meta-evidence does not need to arise from observations about indistinguishable theories, though!

Here's a crude example: If I drop a lot of different objects, eventually I will arrive at the theory All Objects Drop. If I then find a new object of a type I have never seen before... I will expect it to drop.

Did I understand your point? Is the above clear?

[chezlaw]

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There are no cases where one of two theories undecidable by normal evidence have been shown to be true, so if you apply meta-evidence you have no normal evidence that the meta-evidence approach is valid.

[/ QUOTE ]
I don't know what you mean by "normal" evidence, but there have been lots of examples of situations where competing theories existed, no experiments had been done to figure out which (if either) was right, and then later somebody came up with an experiment.

The general rule in those situations is that the simpler theory turns out to be the one that is correct. From that we can infer that, in general, simpler theories do better than more complicated theories.

This is not coincidence, by the way. The reason that more complicated theories often fare worse is that the traditional way of making a theory more complicated is to add more stuff onto it. There are more ways to add incorrect stuff than to add correct stuff -- so the more you add, the more likely you are to get some of it wrong.

This is why "the earth travels around the sun" is more likely to be correct than "the earth travels around the sun because it is being pushed by invisible angels." Whenever you add extra stuff on, you are increasing your exposure to potential error.

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I agree with all of that but its different. I'm talking about two theories that make no different predictions, not ones that cannot yet be tested.

This is the key I think. Rational belief on the basis of evidence is only meaningful if there is in principle some way of deciding which theory is correct.

chez

[ QUOTE ]


Quote:
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You have artificially constructed a theorem that explicitly refuses to give "evidence" any weight and then reach the unsurprising conclusion that if anyone holds a belief one way or another they cannot do so based on the evidence.

I.e., the conclusion is tautological from your premise that the answer can only be known after we die.

I believe in science. I believe in evidence. I reject your premise.


--------------------------------------------------------------------------------


The argument is in no way an attack on science, nor is there a trick. I would argue that the proposition E is a foundation stone for science.

What do you mean by you reject the premise. All I'm saying is that two theorems that predict the same evidence cannot be decided between on the basis of the evidence. this is true isn't it? so how could you reject it.

chez

[/ QUOTE ]

You call TI a theory, I call it a premise. It can be both. My point remains valid regardless: If you assume away any role for "evidence" then obviously there is no role for evidence. That is not a meaningful proof, it's a tautology.

[chezlaw]

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[ QUOTE ]


Quote:
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You have artificially constructed a theorem that explicitly refuses to give "evidence" any weight and then reach the unsurprising conclusion that if anyone holds a belief one way or another they cannot do so based on the evidence.

I.e., the conclusion is tautological from your premise that the answer can only be known after we die.

I believe in science. I believe in evidence. I reject your premise.


--------------------------------------------------------------------------------


The argument is in no way an attack on science, nor is there a trick. I would argue that the proposition E is a foundation stone for science.

What do you mean by you reject the premise. All I'm saying is that two theorems that predict the same evidence cannot be decided between on the basis of the evidence. this is true isn't it? so how could you reject it.

chez

[/ QUOTE ]

You call TI a theory, I call it a premise. It can be both. My point remains valid regardless: If you assume away any role for "evidence" then obviously there is no role for evidence. That is not a meaningful proof, it's a tautology.

[/ QUOTE ]
Exactly, I'm amazed how many people want to reject a tautology, I tried to be clear but maybe I failed.

So do we all agree, two theories that make no different predictions about the world cannot be decided on the basis of evidence is a tautology, hence it is true.

chez

[maurile]

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So do we all agree, two theories that make no different predictions about the world cannot be decided on the basis of evidence is a tautology, hence it is true.

[/ QUOTE ]
In that sentence, are you using "predictions about the world" as a synonym for "statements of any kind," or as a synonym for "testable predictions."

If you mean "statements of any kind," then the theories are identical -- in which case we don't have two theories, but one (making your claim a tautology).

If you mean "testable predictions," then I will say that, for meta-evidential reasons, "the earth goes around the sun" is more likely to be true than "the earth goes around the sun because it is being pushed by invisible angels" even though the two "theories" make all the same testable predictions.

Theory 1a: Lightning is forged by Hephaestus and sent to earth by Zeus.
Theory 1b: Lightning is an electrostatic discharge... etc. etc. (the details can be easily found on the web).

Theory 2a: Volcanic eruptions are caused by the Goddess Pele using her magic stick Pa'oa and earthquakes are caused by her stamping her feet (both of which occur when she is angry).
Theory 2b: Volcanic eruptions are driven by the ascent of magma.. etc. etc. (the details can be easily found on the web)

Theory 3a: Angels move the planets.
Theory 3b: See Newton, Einstein, etc.

Lather, rinse, repeat.

Suppose that you will grant me that all the 'b's are accepted as true and all the 'a's rejected. Then one could form the theory, based on this evidence, that supernatural agents are unnecessary to explain natural events. On the basis of that theory, we can choose between your god/no god theories...

[ QUOTE ]
In that sentence, are you using "predictions about the world" as a synonym for "statements of any kind," or as a synonym for "testable predictions."

If you mean "statements of any kind," then the theories are identical -- in which case we don't have two theories, but one (making your claim a tautology).

If you mean "testable predictions," then I will disagree and say that, for meta-evidential reasons, "the earth goes around the sun" is more likely to be true than "the earth goes around the sund because it is being pushed by invisible angels" even though the two "theories" make all the same testable predictions.

[/ QUOTE ]

I don't think that's what he's saying (not that I'm too clear on it by any stretch), but I think it's basically that if there are two (non-identical) statements about something having nothing to do with the empirical world, then there's no evidence that can be offered for or against either.

E.g.: T1: In heaven all houses are yellow
T2: In heaven all houses are green.

Well then, yeah, I guess he's logically correct that there isn't any evidence that is relevant, but that's because "evidence" connotes an observable fact and his "theories" expressly provide that they have nothing to do with the observable world.

So it's a logically valid, I suppose, it's just meaningless and unhelpful.

[maurile]

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T1: In heaven all houses are yellow
T2: In heaven all houses are green.

[/ QUOTE ]
Okay, but in that case the two are equally simple.

If we changed it to:

T1: In heaven all houses are yellow.
T2: In heaven all houses are green and have doorbells that sound like tamborines.

I'd bet on T1 if I had to bet.

[chezlaw]

[ QUOTE ]
[ QUOTE ]
In that sentence, are you using "predictions about the world" as a synonym for "statements of any kind," or as a synonym for "testable predictions."

If you mean "statements of any kind," then the theories are identical -- in which case we don't have two theories, but one (making your claim a tautology).

If you mean "testable predictions," then I will disagree and say that, for meta-evidential reasons, "the earth goes around the sun" is more likely to be true than "the earth goes around the sund because it is being pushed by invisible angels" even though the two "theories" make all the same testable predictions.

[/ QUOTE ]

I don't think that's what he's saying (not that I'm too clear on it by any stretch), but I think it's basically that if there are two (non-identical) statements about something having nothing to do with the empirical world, then there's no evidence that can be offered for or against either.

E.g.: T1: In heaven all houses are yellow
T2: In heaven all houses are green.

Well then, yeah, I guess he's logically correct that there isn't any evidence that is relevant, but that's because "evidence" connotes an observable fact and his "theories" expressly provide that they have nothing to do with the observable world.

So it's a logically valid, I suppose, it's just meaningless and unhelpful.

[/ QUOTE ]
Got there. It's logically valid but the reason I brought it up is that people keep claiming that we should have beliefs about which of two theories are true when there's absolutely no way ever of deciding between them.

I say that it is meaningless to talk about which of the theories is true but I get told I'm being silly or wishy-washy and should make a decision based on the evidence.

chez

[chezlaw]

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[ QUOTE ]
That is where meta-evidence comes in. /images/graemlins/wink.gif

I guess it depends on why the two theories make the same predictions. If it's because the theories are identical, then one is as good as the other.

But if they are not identical, it's just that they differ only with respect to statements that are not testable, then one can still be right and the other wrong -- although it is impossible for us to determine empirically which (if either)is right and which is wrong.

In that case, I think the meta-evidentiary principle is relevant.

[/ QUOTE ]

but no-one ever answers the meta-evidence questions. There are no cases where one of two theories undecidable by normal evidence have been shown to be true, so if you apply meta-evidence you have no normal evidence that the meta-evidence approach is valid.

Hence meta-evidence is a fancy word for something that is not based on evidence.

[/ QUOTE ]

I don't think this is correct, if I understand what you are claiming. One is using meta-evidence as support for a meta-theory about which of the two indistinguishable theories is likely to be correct. That meta-evidence does not need to arise from observations about indistinguishable theories, though!

Here's a crude example: If I drop a lot of different objects, eventually I will arrive at the theory All Objects Drop. If I then find a new object of a type I have never seen before... I will expect it to drop.

Did I understand your point? Is the above clear?

[/ QUOTE ]
Possibly /images/graemlins/smile.gif. If you can give one (preferably many) examples of when one of two indestinguishable theories has been shown to be correct then you would have some evidence as to how to form beliefs about them.

I'm saying they're are no such examples (logically there never could be) and hence there is no meta-evidence analagous to things falling.

chez

[benjdm]

Believing a God exists who has not interfered / will not interfere with the physical universe since its creation is indistinguishable from atheism anyway.

[chezlaw]

[ QUOTE ]
Theory 1a: Lightning is forged by Hephaestus and sent to earth by Zeus.
Theory 1b: Lightning is an electrostatic discharge... etc. etc. (the details can be easily found on the web).

Theory 2a: Volcanic eruptions are caused by the Goddess Pele using her magic stick Pa'oa and earthquakes are caused by her stamping her feet (both of which occur when she is angry).
Theory 2b: Volcanic eruptions are driven by the ascent of magma.. etc. etc. (the details can be easily found on the web)

Theory 3a: Angels move the planets.
Theory 3b: See Newton, Einstein, etc.

Lather, rinse, repeat.

Suppose that you will grant me that all the 'b's are accepted as true and all the 'a's rejected. Then one could form the theory, based on this evidence, that supernatural agents are unnecessary to explain natural events. On the basis of that theory, we can choose between your god/no god theories...

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I like this post, maybe we can grab hold of this meta-evidence idea.

On one hand you have theories that can be distingished by evidence. On the other you have theories that cannot be distingished by evidence.

Do you have any evidence that you can extrapolate from one to the other?

chez

[ QUOTE ]
Possibly . If you can give one (preferably many) examples of when one of two indestinguishable theories has been shown to be correct then you would have some evidence as to how to form beliefs about them.

I'm saying they're are no such examples (logically there never could be) and hence there is no meta-evidence analagous to things falling.


[/ QUOTE ]

I can't show you any such examples without circularity, but I don't have to, and that was the point of my "things falling" example. One of the points of theory is to be able to generalize! In my analogy, the actual objects dropped match up with theories that we actually can independently distinguish. The theory this induces, All Things Drop, matches up with the No Supernatural Explanations theory. The new type of object that we have never observed before matches up with "indistinguishable" theories...

[chezlaw]

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[ QUOTE ]
Possibly . If you can give one (preferably many) examples of when one of two indestinguishable theories has been shown to be correct then you would have some evidence as to how to form beliefs about them.

I'm saying they're are no such examples (logically there never could be) and hence there is no meta-evidence analagous to things falling.


[/ QUOTE ]

I can't show you any such examples without circularity, but I don't have to, and that was the point of my "things falling" example. One of the points of theory is to be able to generalize! In my analogy, the actual objects dropped match up with theories that we actually can independently distinguish. The theory this induces, All Things Drop, matches up with the No Supernatural Explanations theory. The new type of object that we have never observed before matches up with "indistinguishable" theories...

[/ QUOTE ]
Lets have a go at making this precise.

T1, T2 are distingusishable on the basis of evidence and we have found that the true one requires nothing supernatural

same goes for T3, T4 ...

generalisation

For all x,y: If Tx, Ty are distingusishable on the basis of evidence then the true one requires nothing supernatural.

I think that's analogous to your objects dropping but its not the result you need.

Somehow you have to make a leap to claims about which of two indistinguishable theories are true.

chez

[ QUOTE ]
On one hand you have theories that can be distingished by evidence. On the other you have theories that cannot be distingished by evidence.

Do you have any evidence that you can extrapolate from one to the other?

[/ QUOTE ]

The No Supernatural Explanations theory applies on the face of it to the god/no god pair of theories. The point of theory making in general is to extrapolate, even to situations that are counterfactual and thus can never be directly tested. You could ask on what basis is any theory generalized from data... what evidence do you have that the new data will obey the same rules as the old? At some point an inductive bias is needed. I will grant you that.

[chezlaw]

[ QUOTE ]
[ QUOTE ]
On one hand you have theories that can be distingished by evidence. On the other you have theories that cannot be distingished by evidence.

Do you have any evidence that you can extrapolate from one to the other?

[/ QUOTE ]

The No Supernatural Explanations theory applies on the face of it to the god/no god pair of theories. The point of theory making in general is to extrapolate, even to situations that are counterfactual and thus can never be directly tested. You could ask on what basis is any theory generalized from data... what evidence do you have that the new data will obey the same rules as the old? At some point an inductive bias is needed. I will grant you that.

[/ QUOTE ]
I think our other discussion in this thread is probably clearer (my post above). can we let this sub-thread die and persue that one? No need to reply to this post if this is ok with you /images/graemlins/smile.gif

chez

[Piers]

You really like multiple neagtives don't you.

I think I remeber a post of yours with a hextruple negative in it /images/graemlins/ooo.gif

[chezlaw]

[ QUOTE ]
You really like multiple neagtives don't you.

I think I remeber a post of yours with a hextruple negative in it /images/graemlins/ooo.gif

[/ QUOTE ]

This is me trying to be clear /images/graemlins/smile.gif

Anyone you said 'people tend to use ....'

I responded with 'either people dont use .... or .... is not on the basis of evidence'

I don't think there's a double negative there or I think its not the case that there wasn't no double negative. /images/graemlins/tongue.gif

chez

[chezlaw]

[ QUOTE ]
[ QUOTE ]
T1: In heaven all houses are yellow
T2: In heaven all houses are green.

[/ QUOTE ]
Okay, but in that case the two are equally simple.

If we changed it to:

T1: In heaven all houses are yellow.
T2: In heaven all houses are green and have doorbells that sound like tamborines.

I'd bet on T1 if I had to bet.

[/ QUOTE ]
Is this what you're saying?

T1 'make some stuff up'
T2 'make more stuff up than T1 did'

T2 is more likely to be wrong than T1

chez

[Piers]

I think there is a trick you can use

Not A !or Not B = A !or B

So how about:

People either use some sort of induction deduction combination or they use evidence.

Or maybe even

If people use some sort of induction deduction combination, then they are not using evidence.

(Well clearly they are using evidence, but the evidence is indirect. The evidence they used as a basis for their induction, or the evidence they used as a parameter in their deduction.)

[chezlaw]

[ QUOTE ]
People either use some sort of induction deduction combination or they use evidence.

[/ QUOTE ]

I'm not sure if your joking or I was even less clear than I thought but no variation of the above is what I said.

chez

Attempt 2 at a response:

For every theory, there exists another theory (an infinity of them, actually) that is indistinguishable based on the evidence. To accept any theory at all, one needs some sort of inductive bias (which means what it sounds like), the classic example being Occam's razor.

My point is that there may be ways of learning, based on evidence, good inductive biases. Obviously relying on evidence must end at some level, though, or there would be infinite regress.

Back to proving that I suck at poker.

[chezlaw]

[ QUOTE ]
Attempt 2 at a response:

For every theory, there exists another theory (an infinity of them, actually) that is indistinguishable based on the evidence. To accept any theory at all, one needs some sort of inductive bias (which means what it sounds like), the classic example being Occam's razor.

My point is that there may be ways of learning, based on evidence, good inductive biases. Obviously relying on evidence must end at some level, though, or there would be infinite regress.


[/ QUOTE ]
Its true that if you are to distinguish between the theories that you need some method of doing so but if the theories don't make different claims about the world then we it may be that they can't be distinguished between.

So we end up using something like Ockhams razor but there's plenty of problems in deciding which theory is simpler which is why we need evidence, except of course in the cases we are discussing when there isn't any /images/graemlins/smile.gif

When it comes to god, the theists will always claim god is simpler and ant-theist will always claim no god is simpler. Hence athiesm (as in not believing in god rather than believing in no god).

Its been interesting, thanks.

chez