Labels: Atheist/Vegan - Why are they scary to some?

[inator]

Those are good points, thanks for taking the time to dissect my answer. It's true that I'm generally more focused on empiricism than on rationalism.

It's possible to use logic to prove something false when that thing violates logic through contradiction. In this way, the logical possibility of the existence of these things depends on their definitions. The empirical reality is subservient to that; anything that is logically impossible must also be empirically false.

In empirical matters, that's usually a good call. Although in philosophical and logical matters, any demonstrated truth is by its nature absolute, unless there is a fallacy or contradiction in its demonstration.

My understanding is that there is no a priori knowledge available to us to be demonstrated or contradicted. Every cognitively meaningful sentence can be assigned to one of two categories: either (1) it's a tautology, and so true only because of the definition of its terms and provides no substantive information about the world, or (2) it's open to empirical verification (see AJ Ayer). There is, then, no room for knowledge about the external world solely by intuition or deduction.
Sure, intuition and deduction can provide us with knowledge like in mathematical analysis and logic, but that's only knowledge of the relations of our own ideas and not substantive knowledge about the external world. We can only intuit and deduce truths from knowledge that has already been obtained, a posteriori. Otherwise you end up with a regress argument, since every proposition must be justified by other propositions in order to maintain its validity - and that can go on for ever.

In this way, logic works in a different way from empiricism, practically, proving (absolutely) things to be false, instead of providing evidence (provisionally) for things to be true (or discrediting that evidence).

True, things can be indeed proven wrong if a particular theory contradicts facts already known to us through experience, i.e. evidence. Essentially, what works may or may not be true, but what fails can't be true because the truth always works.
On the other hand, truth ascribed to repeated testing should be "self-corrective" over time. So our present truth is probably yet to be corrected.

False; without any empirical data on the subject, we do not know and can not evaluate probability. Probability is an empirical matter, based on evidence for or against something.

In terms of rational analysis, however, we should prefer simpler explanations, even without empirical evidence; i.e. Occam's razor. And this is why a rational person should practically disregard these prospects.

Our preference for simplicity isn't a given, it needs justification.
We can justify preferring the simplest explanation as a direct result of basic probability theory. By definition, all assumptions introduce possibilities for error. If an assumption does't improve the accuracy of a theory, its only effect is to increase the probability that the overall theory is wrong.
We can also justify simplicity by the falsifiability criterion - we prefer simpler theories to more complex ones because their empirical content is greater and because they are better testable.

There are statements that are absolutely true by logical necessity.
Most apologists believe their god is true by logical necessity; but they fail to demonstrate this through logical proof (to the contrary, every definition they propose has been debunked, proved logically contradictory, or rejected as not resembling common usage).

They fail to demonstrate this because there is no solely logical proof for external events - proof is based on experience.

The latter are also atheists, but it's not an appropriate definition of atheism, because atheism includes both groups. The more inclusive definition is the more useful and appropriate one.
We should reject incorrect definitions, because they cause people to be misinformed and misunderstand the situation.

I agree.

[brimstoneSalad]

Those are good points, thanks for taking the time to dissect my answer.

No problem.

My understanding is that there is no a priori knowledge available to us to be demonstrated or contradicted.

Logic is necessary knowledge, although you can call that tautological of a sort, certain definitions are not simply arbitrary systems (as language may be seem to be), but defined by inherent necessity.

There is, then, no room for knowledge about the external world solely by intuition or deduction.

Not so, but that is a very complicated issue.

Some things, principles, properties of the universe are innately necessary. Defining these principles and demonstrating why they are necessary is potentially very difficult, but they are there.
Something can be demonstrated true by logic, for example, by demonstrating every alternative to be contradictory.

Unified field theorum would be expected to be just such a thing. Things are being churned down to their most rudimentary parts. Some people expect to find 'God' at the bottom of all of that. I would expect to find derivation from the basic laws of logic.

Logic -> Unified field -> All Science (the equation that models the multiverse).

Sure, intuition and deduction can provide us with knowledge like in mathematical analysis and logic, but that's only knowledge of the relations of our own ideas and not substantive knowledge about the external world.

I would call that substantive, but it is also inherently incomplete on one important way: The information from quantum "collapse".

We could derive and model the multiverse with complete elegance, but just having the map doesn't tell us our present address. That is, it ONLY tells us what's true in all universes, but does not tell us specifically what is true in "our" universe.
Solving science completely doesn't tell us specific empirical data, like what's under a particular rock, without checking.

We can only intuit and deduce truths from knowledge that has already been obtained, a posteriori. Otherwise you end up with a regress argument, since every proposition must be justified by other propositions in order to maintain its validity - and that can go on for ever.

It depends on what truths you are looking for.
As I said, we can derive certain truths for ALL universes. So, if something by necessity must exist in all universes, we can speak meaningfully about it.
Also, we can speak meaningfully about something that can not exist in ANY universe.

The only limit we have is in determining whether something exists or not for US when it is certain to exist in some universes, but not all universes. That's a gamble. And that's where only empirical data can help us.

But here's a very important point: The issue of contention with which theists are concerned is something that can be resolved without any empirical data, because it is one that relates to all universes.
If a theist asserts that his or her god exists in some universes but not others, then it can not be proved to exist by logic (although it may yet be proved to not exist if within it can be demonstrated a contradiction).

True, things can be indeed proven wrong if a particular theory contradicts facts already known to us through experience, i.e. evidence.

No no, I'm talking about something contradicting itself, or a truth which is necessary through logic alone.
Can a god make a rock so heavy that he can not lift it? That kind of thing. Unresolved contradictions and paradoxes.

Empiricism does not give us certain knowledge, just provisional knowledge (which is very useful, but not usually of much concern to theists).

On the other hand, truth ascribed to repeated testing should be "self-corrective" over time. So our present truth is probably yet to be corrected.

This is more an issue of precision than accuracy.

If an assumption does't improve the accuracy of a theory, its only effect is to increase the probability that the overall theory is wrong.

False: Accuracy is meaningless without precision.

You think of a random real number, and I tell you it's a number between negative infinity, and positive infinity. I am 100% accurate, and 0% precise.

My answer is useless. Incidentally, so is your answer on god. Which is why it is so frustrating.

Additional information increases the knowledge being represented through precision. We should prefer both precision and accuracy, not one at the expense of the other.

When something seems to increase precision more than it decreases accuracy, it should be preferred even at a risk of decreasing accuracy. You can always be 100% accurate, if that's your goal, by being uselessly generic and noncommittal.

We can also justify simplicity by the falsifiability criterion - we prefer simpler theories to more complex ones because their empirical content is greater and because they are better testable.

Also false. I think I explained that above. They're also not better testable; testability is a very different issue (and we should prefer testable theories, when they deal with testable empirical information, but that doesn't justify Occam's razor).

As far as I know at the moment, Occam's razor is not externally justified, but just a rational principle. Indeed, it may define rationality, in the common sense. It may be a tautology.

[inator]

Logic is necessary knowledge, although you can call that tautological of a sort, certain definitions are not simply arbitrary systems (as language may be seem to be), but defined by inherent necessity.

Some things, principles, properties of the universe are innately necessary. Defining these principles and demonstrating why they are necessary is potentially very difficult, but they are there.
Something can be demonstrated true by logic, for example, by demonstrating every alternative to be contradictory.
Unified field theorum would be expected to be just such a thing. Things are being churned down to their most rudimentary parts. Some people expect to find 'God' at the bottom of all of that. I would expect to find derivation from the basic laws of logic.
Logic -> Unified field -> All Science (the equation that models the multiverse).

Necessary knowledge - yes, innate knowledge - no. I'm not actually disagreeing or saying that certain logical principles are futile arbitrary systems.
I'm just saying that they are not actual knowledge about the external world, but only tools to obtain that knowledge. While experience is always a priory, logic leads us to gain, through a multilayered interpretation of experience, more general knowledge than what can be gained by simple observation.
But it still does that by deducing and deriving truths from initial pieces of observable information, and not directly from some sort of innate ideas. Knowledge can't entirely exclude empirism.

I would say: Observations -> Logic -> Theory of everything -> All Science

I would call that substantive, but it is also inherently incomplete on one important way: The information from quantum "collapse".

We could derive and model the multiverse with complete elegance, but just having the map doesn't tell us our present address. That is, it ONLY tells us what's true in all universes, but does not tell us specifically what is true in "our" universe.
Solving science completely doesn't tell us specific empirical data, like what's under a particular rock, without checking.

As I said, we can derive certain truths for ALL universes. So, if something by necessity must exist in all universes, we can speak meaningfully about it.
Also, we can speak meaningfully about something that can not exist in ANY universe.
The only limit we have is in determining whether something exists or not for US when it is certain to exist in some universes, but not all universes. That's a gamble. And that's where only empirical data can help us.

But here's a very important point: The issue of contention with which theists are concerned is something that can be resolved without any empirical data, because it is one that relates to all universes.
If a theist asserts that his or her god exists in some universes but not others, then it can not be proved to exist by logic (although it may yet be proved to not exist if within it can be demonstrated a contradiction).

This is a difficult matter and I suppose it depends quite a lot on what type of multiverse proposal you are talking about, there are so many. If you're referring to the multiverse theory derived from quantum mechanics, then you are trying to avoid the collapse altogether and say that all possible outcomes of a situation do occur — in their own separate universes, each corresponding to a specific basis state of the multiverse superposition.

There is uncertainty in the many-worlds interpretation that follows from each observer within any universe having no knowledge of what goes on in the other universes. The only general truth that could be known is what kind of multiverse it is, and that simply depends on what theory you derive it from.

I'ts hard to say whether there's really a fundamental reality that this kind of quantum state describes or if it's just a prescription for calculating experimental results. The way I see it, the wave function of probabilities doesn't say what the state of a system fundamentally is, only what the result of observations might be.

I think that many theorists who talk about the multiverse, especially those who derive it from quantum theory or even string theory, don't care much about parallel universes per se. The lack of empirical testability or falsifiability is not a major concern to them because these theories live or die based on internal consistency. I think this is the sort of stuff that you might be referring to.
Laboratory testing might one day find evidence and prove some of it right. Until then, even if the theory works, it's just speculation. On the other hand, lack of evidence wouldn't really prove it wrong. So, lacking falsifiability, it's more of a philosophical rather than scientfic question. Not that there's anything wrong with scientifically based philosophical speculation.

There are also rather sophisticated theological thinkers out there who do something similar. However their problem is usually not only the lack of falsifiability, but also, as you said, the internal inconsistency of their theory.

No no, I'm talking about something contradicting itself, or a truth which is necessary through logic alone.
Can a god make a rock so heavy that he can not lift it? That kind of thing. Unresolved contradictions and paradoxes.

Well this kind of contradiction stems from making unjustified assumptions that have no basis in reality, all to support a particular explanation. It's exactly what science is trying to avoid doing.

This is more an issue of precision than accuracy.

False: Accuracy is meaningless without precision.
You think of a random real number, and I tell you it's a number between negative infinity, and positive infinity. I am 100% accurate, and 0% precise.
My answer is useless. Incidentally, so is your answer on god. Which is why it is so frustrating.
Additional information increases the knowledge being represented through precision. We should prefer both precision and accuracy, not one at the expense of the other.
When something seems to increase precision more than it decreases accuracy, it should be preferred even at a risk of decreasing accuracy. You can always be 100% accurate, if that's your goal, by being uselessly generic and noncommittal.

Also false. I think I explained that above. They're also not better testable; testability is a very different issue (and we should prefer testable theories, when they deal with testable empirical information, but that doesn't justify Occam's razor).
As far as I know at the moment, Occam's razor is not externally justified, but just a rational principle. Indeed, it may define rationality, in the common sense. It may be a tautology.

Yes, we should contrast accuracy and precision in this context.

The idea here is that among competing hypotheses that predict equally well/have the same precision, we should choose the simplest one - the one with the fewest assumptions. Every additional assumption introduces possibilities for error and that can mess up accuracy.
While it's true that accuracy without precision can be meaningless, the reverse is also true. Sure, more complicated solutions can sometimes provide more precise predictions, but, in the absence of differences in predictive ability, the fewer assumptions that are made, the better.

In its practical use, I think that Occam's razor isn't necessarily used as an arbiter between theories, but more as a technique that guides scientists in the development of elegant theoretical models.
I don't really see it as an innate principle of logic when it comes to the scientific method. The preference for simplicity is based on the falsifiability criterion. For each accepted explanation of a phenomenon, there is always an infinite number of possible and more complex alternatives, because one can always burden failing explanations with ad hoc hypothesis to prevent them from being falsified.

Sorry for the super late reply

[brimstoneSalad]

Necessary knowledge - yes, innate knowledge - no. I'm not actually disagreeing or saying that certain logical principles are futile arbitrary systems.
I'm just saying that they are not actual knowledge about the external world, but only tools to obtain that knowledge.

They are knowledge about the external world, though. You don't seem to have followed my point. It is very generalized and limited knowledge, but it is knowledge.

Well this kind of contradiction stems from making unjustified assumptions that have no basis in reality, all to support a particular explanation. It's exactly what science is trying to avoid doing.

Do you deny that it is knowledge to be able to say something like "there is no such thing as an omnipotent god"?

Knowledge through logic alone is possible. Although it usually deals with what is NOT true of our reality (due to internal contradictions), it can also in some circumstances deal with what IS true through process of elimination.

Logic isn't limited to exclusively extrapolating from empirical data. It's just much easier to do.

This is a difficult matter and I suppose it depends quite a lot on what type of multiverse proposal you are talking about, there are so many.

Not really. There's only one of any note.

Also, it's an interpretation. Based on logic.

If you're referring to the multiverse theory derived from quantum mechanics, then you are trying to avoid the collapse altogether and say that all possible outcomes of a situation do occur — in their own separate universes, each corresponding to a specific basis state of the multiverse superposition.

Not avoid it, there's no reason to assume collapse is true or logically coherent. Occam's razor.

There is uncertainty in the many-worlds interpretation that follows from each observer within any universe having no knowledge of what goes on in the other universes.

That's what I said.

The only general truth that could be known is what kind of multiverse it is, and that simply depends on what theory you derive it from.

That depends on the UFT.

I'ts hard to say whether there's really a fundamental reality that this kind of quantum state describes or if it's just a prescription for calculating experimental results.

I don't agree with that.

The way I see it, the wave function of probabilities doesn't say what the state of a system fundamentally is, only what the result of observations might be.

That's what I said. And yet, do you deny that this kind of thing is knowledge?

So, lacking falsifiability, it's more of a philosophical rather than scientfic question. Not that there's anything wrong with scientifically based philosophical speculation.

Like I said, it's an interpretation. Taking what we know, and applying logic to it. It can also be derived without any empirical data at all.

There are also rather sophisticated theological thinkers out there who do something similar. However their problem is usually not only the lack of falsifiability, but also, as you said, the internal inconsistency of their theory.

There aren't any I know of. Theologians don't provide interpretations based on logic, they provide ad hoc hypotheses. When they use the jargon stolen from science, it may seem similar, but they're worlds apart.

Well this kind of contradiction stems from making unjustified assumptions that have no basis in reality, all to support a particular explanation. It's exactly what science is trying to avoid doing.

And yet, we can conclude with logic alone that these hypotheses are false, because they are incoherent. That, at least, these particular concepts of god do not reflect anything that exists in our universe or any other.

The idea here is that among competing hypotheses that predict equally well/have the same precision, we should choose the simplest one - the one with the fewest assumptions. Every additional assumption introduces possibilities for error and that can mess up accuracy.

This is correct. But you can not compare hypotheses with varying levels of precision, as you seemed to be doing before. There is no means to normalize them. Not exchange rate for precision and accuracy.

[inator]

Taking what we know, and applying logic to it. It can also be derived without any empirical data at all.

Also, it's an interpretation. Based on logic

.

Without any new empirical data. As you said, it's derived from what we know. What we know is derived from other things that we know. And so on, till you get to that one piece of observable information that made it all possible. In this case, this particular multiverse theory can be traced back to observations of subatomic particles. But the process is an interpretation of facts by logic, yes.
Experience is a fundamental part of knowledge. What would we know about the outside world if we had no senses through which to experience it (or ourselves)?

The way I see it, the wave function of probabilities doesn't say what the state of a system fundamentally is, only what the result of observations might be.

That's what I said. And yet, do you deny that this kind of thing is knowledge?"

That's not what I'm denying here. I'm only questioning whether what we understand as probability in quantum mechanics actually describes a mutiverse or whether probability is just that: a probability of occuring events. I don't know what it is and I won't assume anything one way or the other.
The wave function is knowledge and it stems from repeated interpretation of some particular observations, not from thin air.

And yet, we can conclude with logic alone that these hypotheses are false, because they are incoherent. That, at least, these particular concepts of god do not reflect anything that exists in our universe or any other.

Do you deny that it is knowledge to be able to say something like "there is no such thing as an omnipotent god"? Knowledge through logic alone is possible. Although it usually deals with what is NOT true of our reality (due to internal contradictions), it can also in some circumstances deal with what IS true through process of elimination.
Logic isn't limited to exclusively extrapolating from empirical data. It's just much easier to do.

Omnipotence is the element that is impossible here. The proposition implies its own negation. Does deciding that a paradoxical definition does not actually define anything say something about the world? Does it contain more information than saying "This statement is false."?
I'm not sure if refuting a self-refuting statement is actual knowledge. It might be some sort of tautology.

That depends on the UFT.
Not really. There's only one of any note.

It does depend on the UFT, but since we don't have one yet, there are multiple multiverse propositions. Most of them can even coexist since they don't contradict each other. The brane multiverse and the cyclic one are quite interesting and probably the most talked about right now.

Not avoid it, there's no reason to assume collapse is true or logically coherent. Occam's razor.

Is the multiverse the simplest explanation? Maybe. However, considering the scale that quantum mechanics applies to, a quantum multiverse explanation might not turn out to be that simple either.

There aren't any I know of. Theologians don't provide interpretations based on logic, they provide ad hoc hypotheses. When they use the jargon stolen from science, it may seem similar, but they're worlds apart.

Some tried to prove the existence of God based on logic. I'd give the example of Aquinas, though I'm not sure whether finding arguments for a conclusion given in advance is philosophy. Plus the internal contradictions, of course.

This is correct. But you can not compare hypotheses with varying levels of precision, as you seemed to be doing before. There is no means to normalize them. Not exchange rate for precision and accuracy.

That's not what I was trying to do, it might have come out unclear.

[brimstoneSalad]

Without any new empirical data.

No, also without any.
Are you familiar with the process of elimination? That's how it works.
The MWI could have been obvious to a philosopher in ancient Greece, to explain how things appear to be, and why something is rather than isn't, but it just hadn't occurred to anybody because it's such an unintuitive thing.

The problem of existence that theists harp on IS a real philosophical issue, and it's one that demands a solution. Their proposed solution is just invalid.

What we know is derived from other things that we know. And so on, till you get to that one piece of observable information that made it all possible.

I don't agree with that assertion, and you don't have any evidence for it.
This comes back to the agnostic thing.

You're making an assertion about the world, that logic can't give us information in itself about the world, and appealing to logic to do it -- or if you aren't, then you're presenting an assertion without evidence which you should not by your very principles accept.

Follow? You're contradicting yourself by making this claim about empirical exclusivity without empirical evidence.
Which is it? Can or can not logic tell us something about the world on its own? And if it can't, you need to provide empirical proof of that (which you can never do), or logical proof of it, which would refute your very claim.

What would we know about the outside world if we had no senses through which to experience it (or ourselves)?

We can know what we can reason about it. And we can reason quite a bit more than you assume we can. Although that doesn't necessarily mean we will have the creativity or reasoning capacity to do so; it's just something open to us, if we are genius enough.

If you want to call reasoned conclusions "not information about the world", you're just committing a no true Scotsman fallacy.

I'm only questioning whether what we understand as probability in quantum mechanics actually describes a mutiverse or whether probability is just that: a probability of occuring events.

It describes a multiverse.

I don't know what it is and I won't assume anything one way or the other.

You don't have to assume. It's logically apparent.

I'm not sure if refuting a self-refuting statement is actual knowledge. It might be some sort of tautology.

Define knowledge, then. Should we get out the dictionary to define Scotsman while we're at it too.

It does depend on the UFT, but since we don't have one yet, there are multiple multiverse propositions.

In my original statement, I assumed the UFT had been found.
And when it is, it should be something incredibly obvious, through logic, like relativity should have been.
And yes, I believe that we could have reasoned the truth of special relativity in Ancient Greece without an iota of empirical evidence. IF we had the genius and presence of mind to do so and comprehend the complexity of the proof required to demonstrate it.

People can and do reject things that are logically proven all of the time, though, so that wouldn't mean it would have been accepted.

Is the multiverse the simplest explanation?

Yes. It's a simple, literal interpretation of the math, without all of the absurd rationalizations people have hung on it based on their fears or discomfort.

However, considering the scale that quantum mechanics applies to, a quantum multiverse explanation might not turn out to be that simple either.

That doesn't make any sense...

Some tried to prove the existence of God based on logic. I'd give the example of Aquinas, though I'm not sure whether finding arguments for a conclusion given in advance is philosophy. Plus the internal contradictions, of course.

Tried being the key word. Tried and failed terribly. I've studied all of the classics. Unless there's something hiding under a deep dark rock somewhere out there, there just aren't any.
They don't compare on any level. It's like playing a board game with a two year old who doesn't follow the rules and doesn't understand the concept of them.

Theists are just bad at logic.

[inator]

It seems improbable that we're going to resolve this age-old epistemological dispute here, but here goes...

Define knowledge, then. Should we get out the dictionary to define Scotsman while we're at it too.

Smug alert!

Remember the classification of meaningful knowledge: 1) relations of our own concepts, tautology - analytic; or 2) knowledge about the external world - synthetic.

All analytic propositions are known a priori. Because they are true (or false) just in virtue of the meanings of their definitions, we don’t need to check them against sense experience to know whether or not they are true. For instance "black cats are black." or "Parallel lines never meet." Broadly, these are tautologies, their denials would be self-contradictory. But necessary statements like that are empty (that is, they're not in themselves information about the world).

Then there is knowledge that comes after or is dependent upon experience. "Desks are brown" is a synthetic statement. Unlike the analytic statement "Black cats are black", the synthetic statement "Desks are brown" is not necessarily true unless all desks are by definition brown, and to deny it would not be self-contradictory. We would probably refer the matter to experience. Knowledge about the external world depends primarily on synthetic statements - statements that may be true or may be false.

The first is still knowledge, it just doesn't directly give us information about the external world. There no Scotman fallcy in my assigning your example of the internal contradiction of a particular concept to the first category.
We can, I agree, know by intuition that our concept of God includes our concept of omnipotence (which also leads to the internal contradiction). It all depends on definitions of concepts and it's therefore analytic.
The debate only starts with regard to propositions that contain synthetic information about the external world.

I don't agree with that assertion, and you don't have any evidence for it.
This comes back to the agnostic thing.
You're making an assertion about the world, that logic can't give us information in itself about the world, and appealing to logic to do it -- or if you aren't, then you're presenting an assertion without evidence which you should not by your very principles accept.
Follow? You're contradicting yourself by making this claim about empirical exclusivity without empirical evidence.
Which is it? Can or can not logic tell us something about the world on its own? And if it can't, you need to provide empirical proof of that (which you can never do), or logical proof of it, which would refute your very claim.

It's not self-contradicting (like the agnostic thing, which is indeed problematic). We know based on experience that it is more plausible that knowing things about the external world includes the empirical element. That's how science and induction seem to work, it's pretty straightforward. If there was evidence of some other exclusive way of knowing, we'd know something (and somehow) different.

If cognitive processing is not dependent on information acquired from the senses, where is it from? Logic/deduction is the tool by which you derive truths from other truths, but how do you get that initial truth? Think positivism. Is it spontaneous intuition? Was the truth with us all along, as in innate ideas? Divine inspiration?
Saying you know by intuition that you know by intuition is pretty redundant. Naturally, if you claim some truths are innately known to us, one must reject skepticism in relation to those truths. Which makes empiricism simpler (Occam's razor).

We can know what we can reason about it. And we can reason quite a bit more than you assume we can. Although that doesn't necessarily mean we will have the creativity or reasoning capacity to do so; it's just something open to us, if we are genius enough.

To know a proposition, we must believe it and it must be true, but something more is required, something that distinguishes knowledge from a lucky guess. We can form beliefs just by making lucky guesses. How to gain warranted beliefs is less clear.
Moreover, to know the world, we must think about it, and it is unclear how we gain the concepts we use in thought or what assurance, if any, we have that the ways in which we divide up the world using our concepts correspond to divisions that actually exist.
Any intellectual faculty, whether it be sense perception or intuition, provides us with warranted beliefs only if it is generally reliable. The reliability of sense perception stems from the causal connection between how external objects are and how we experience them.

No, also without any.
Are you familiar with the process of elimination? That's how it works.
The MWI could have been obvious to a philosopher in ancient Greece, to explain how things appear to be, and why something is rather than isn't, but it just hadn't occurred to anybody because it's such an unintuitive thing.

In my original statement, I assumed the UFT had been found.
And when it is, it should be something incredibly obvious, through logic, like relativity should have been.
And yes, I believe that we could have reasoned the truth of special relativity in Ancient Greece without an iota of empirical evidence. IF we had the genius and presence of mind to do so and comprehend the complexity of the proof required to demonstrate it.

People can and do reject things that are logically proven all of the time, though, so that wouldn't mean it would have been accepted.

The MWI example is not going to cut it, since it's clearly a concept derived from Schrodinger's equation, which in turn interprets the observed quantum state. Assuming that we fully understand the quantum state and that there are absolutely no incoherences in the derivation of the MWI, we can say that it's true. But it's not yet clear whether those conditions are fully met.
Sure, some have been inspired enough to think of the concept of daughter universes even without understanding QM, it's in movies as well. But, lacking a good theory behind it, it's no more than fantasy.

Would an ancient greek have been able to come up with special relativity? Sure, had/she he been genious enough to put all the signs together (possibly working with less observations than what was available later through technology, but still inducing ideas from observations) and develop all the concepts underlying SR on his own and then also derive SR. That's not impossible, just improbable. It also doesn't contradict induction.
If he had derived multiple possible explanations from a phenomena, he would have taken them by elimination, yes. Some things don't work coherently, but at least one version of what works should be true. What would he be trying to explain had there been no (observation of the) phenomena?

It describes a multiverse.

You don't have to assume. It's logically apparent.

Yes. It's a simple, literal interpretation of the math, without all of the absurd rationalizations people have hung on it based on their fears or discomfort.

It’s a serious idea and it deserves serious discussion, however I don’t think that the case for MWI is a slam-dunk. I view it as a candidate for reality, but we haven't reached the point where we can move it from candidate to settled. Occam’s razor seems like a tough call on these interpretations.
I like your statement that MWI is the interpretation of QM with the least baggage, but I believe the ensemble interpretation might have even less baggage as it doesn’t assume the wavefunction ontologically represents any individual system, but instead the abstraction of that system. This seems more in-line with mathematics as a description and not fundamental in the universe. And the latter position might carry more baggage. I’m not sure of the answer, but dismissing the concern as silly seems unjustified.

That doesn't make any sense...

I'll quickly explain what I mean by that, though it deviates a bit from the main topic.
The problem as I see it is that branches separate too fast for there to be that many consistent macroscopic objects at all. There might already be an explanation for this.
But more importantly, if probabilities can be meaningfully assigned to branches, then the theory is explanatory. But how can it make sense to talk of probabilities (other than 0 and 1) at all, since all 'possible' outcomes do (certainly!) occur? Assertions like 'the probability of spin-up will be 2/3' would be incoherent. Neither does it seem acceptable just to throw out the probabilistic part of the theory: strip quantum mechanics of its quantitative probabilistic assertions, and one has neither a theory that will be of any help in guiding expectations, nor a theory that can be subjected to empirical test. It wouldn’t be explanatory anymore… That would really be a problem.

[brimstoneSalad]

Remember my classification of meaningful knowledge: 1) relations of our own concepts, tautology - analytic; or 2) knowledge about the external world - synthetic.

Here you suggest these things ARE knowledge (point 1)

But you said:

I'm not sure if refuting a self-refuting statement is actual knowledge. It might be some sort of tautology.

Here's the thing:
When you say such and such (referring to something in philosophy, mathematics, anything that's analytic) isn't actual/meaningful "knowledge", it comes off as very dismissive and insulting to those domains, which by any reasonable definition ARE knowledge, and are very important and meaningful knowledge to humanity at that. They are knowledge, and they are actual/true in any regard.

All analytic propositions are known a priori.

Yes, and they are knowledge.

Pi, the ratio of the circumference to the diameter of a circle, is 3.14159265...etc.
We didn't always KNOW that. The exact number wasn't part of the definition of pi, but it was deduced from the definition based on complex mathematical analysis. We gain knowledge every time we extract another significant figure for pi.

Knowledge is a familiarity, awareness or understanding of someone or something, such as facts, information, descriptions, or skills, which is acquired through experience or education by perceiving, discovering, or learning. Knowledge can refer to a theoretical or practical understanding of a subject. It can be implicit (as with practical skill or expertise) or explicit (as with the theoretical understanding of a subject); it can be more or less formal or systematic.[1] In philosophy, the study of knowledge is called epistemology; the philosopher Plato famously defined knowledge as "justified true belief", though "well-justified true belief" is more complete as it accounts for the Gettier problems. However, several definitions of knowledge and theories to explain it exist.

Knowledge acquisition involves complex cognitive processes: perception, communication, and reasoning; while knowledge is also said to be related to the capacity of acknowledgment in human beings.[2]

http://en.wikipedia.org/wiki/Knowledge

Because they are true (or false) just in virtue of the meanings of their definitions, we don’t need to check them against sense experience to know whether or not they are true.

No, not based on the meanings people think they have, not necessarily based on dictionary definitions, but based on the meanings they implicitly have based on logical examination; the meanings they must have in order to be consistent or meaningful.
Just like Pi. You can know more about pi, not by reading the definition, but by doing the work to discover it.

We don't need to check them against sense experience, but there's a distinction between a trivial tautology, like saying "all unmarried men are bachelors" and a more advanced philosophical position, like "Omniscience is logically impossible".

The former is knowledge about the meanings of words and their uses in society perhaps, but the latter goes beyond that by providing knowledge in contradictions to common beliefs, or giving people more knowledge about the innate nature of the subject than is transparently or that is by definition easily apparent to them.

If people think that there's an omniscient being in this world, the knowledge that such a thing is impossible is likely to be news to them. That's meaningful, and it's given meaning by human ignorance, or the shallow level of logical examination most people put to their beliefs.

In many ways, it can be said that logically deduced knowledge, a priori, IS the only true knowledge, and that empirical knowledge is just a guess or an approximation without the possibility of certainty.

That is, that your point #2 is not knowledge, and doesn't really exist.

2) knowledge about the external world - synthetic.

Try this on for size: "well-justified true belief"
How can you call empirical observations true, when you don't really know if they are true or false?

A priori knowledge is knowledge. And it can very well be knowledge about our world, just as it is knowledge about all possible worlds, our world being one of those.

Empirical "knowledge" has much more of a fight on its hands.

But necessary statements like that are empty (that is, they're not in themselves information about the world).

The ratio of a circle's circumference to diameter is 3.14159265...etc.
This IS knowledge, and it is information about our world. It also happens to be information about all possible worlds, of which our world is one.

Information about all possible worlds is also information about our world. It's just not exclusive to our world.

If you want to redefine knowledge, in classical no true Scotsman tradition, to be only information about exclusively our world that does not apply to any other possible world, you've created even a greater challenge for yourself: Now you have to prove that there IS a possible world in which a thing is NOT true, in order to claim it to be knowledge.

Knowledge about the external world depends primarily on synthetic statements - statements that may be true or may be false.

Inductive assumptions do, but knowledge about the external world -- true, certain knowledge -- never does.

There no Scotman's fallcy in my assigning your example of the internal contradiction of a particular concept to the first category.

It was when you said it wasn't knowledge.
Maybe you misspoke.

The first is still knowledge, it just doesn't directly give us information about the external world. [...]
The debate only starts with regard to propositions that contain synthetic information about the external world.

It does give us information about the external world, as I have explained. It tells us about what can not exist, it tells us what's not in the black box, it tells us about ratios and relationships, and sometimes it also tells us what does exist by necessity, or what exists in terms of probability (and probability of truth is all empirical analysis ever gives you either).

And now you clarify "synthetic information about the external world" -- so what is it? Do you deny that analytic information about the external world exists, or accept that there are two kinds of information about the external world, only one of which being synthetic?

We know based on experience that it is more plausible that knowing things about the external world includes the empirical element.

That's just induction, and BAD induction. "All apples are red". You don't know it, you just assume it on the grounds of ignorance. "I haven't seen any green apples, therefore they don't exist".

And the only way you THINK you've experienced that, is because you've arbitrarily decided that green apples aren't real apples, but are tautologies instead.

That's how science and induction seem to work, it's pretty straightforward.

No, it doesn't. Science doesn't make such negative claims based on lack of evidence. Absence of evidence is not evidence of absence.
That kind of thinking is a parody of science, one which theists and new agers attack to try to show how arrogant science is (without understanding how science really works).

If cognitive processing is not dependent on information acquired from the senses, where is it from?

It doesn't matter where it's from. It's just information processing.

Logic/deduction is the tool by which you derive truths from other truths, but how do you get that initial truth?

The a priori knowledge of logic itself is all you need.
Contradictions can prove an apparent 'possibility' false. And the process of elimination can prove the only remaining possibility true. You can derive true information strictly from logic, it's just cognitively difficult.

Is it spontaneous intuition? Was the truth with us all along, as in innate ideas? Divine inspiration?

No, it's reasoned. The root of truth may have been, but it takes hard work and reasoning to unpack it. Although you could, as a cave man, have figured out pi to a billion places, invented calculus, etc. you would be limited in executing that based on your capacity for creative thought and information processing.

Saying you know by intuition that you know by intuition is pretty redundant.

What are you saying? Do you just outright deny logic? Do you deny the law of non-contradiction? Because it's redundant, to you, it's wrong?

Naturally, if you claim some truths are innately known to us, one must reject skepticism in relation to those truths.

It's not because I claim they are, it's because they are. And Skepticism has no meaning without them.

We must be open minded, but not so open minded that our brains fall out. Accepting the law of non-contradiction is as open minded as you can be, because by questioning it, you become closed minded to the possibility of any kind of truth.

Which makes empiricism simpler (Occam's razor).

No it doesn't, empiricism relies on logic and the law of non-contradiction to make any sense and tell us anything of any use or meaning at all. Denying the validity of logic is not simpler. That's absurd.

There are some things, like logic, that we simply know. And skepticism of those things is self-defeating. You can't be skeptical of logic.

To know a proposition, we must believe it and it must be true, but something more is required, something that distinguishes knowledge from a lucky guess. We can form beliefs just by making lucky guesses. How to gain warranted beliefs is less clear.

Not really less clear. A belief is strongly justified if it is known by logical deduction, as I have explained, from logic alone. A negative belief (that something is impossible, as logically demonstrated through contradiction), or a positive belief by way of the process of elimination.

Moreover, to know the world, we must think about it, and it is unclear how we gain the concepts we use in thought or what assurance, if any, we have that the ways in which we divide up the world using our concepts correspond to divisions that actually exist.

Irrelevant, at least regarding logical thought. Skepticism of logic is self defeating.

Any intellectual faculty, whether it be sense perception or intuition, provides us with warranted beliefs only if it is generally reliable.

False. Logic is inherently reliable as long as it is valid, and so inherently justified. There are no means by which to demonstrate it unreliable (if it conflicts with observation, then observation is wrong).

Sense perception is inherently unreliable, or the reliability is unknown. Are we brains in vats? You don't know.

The reliability of sense perception stems from the causal connection between how external objects are and how we experience them.

It's an assumption you make, but you don't know that.

The MWI example is not going to cut it, since it's clearly a concept derived from Schrodinger's equation, which in turn interprets the observed quantum state.

You might as well say "The law of non contradiction isn't going to cut it, because it's clearly a concept derived from the observation of things not contradicting each other".
Or "Natural selection isn't going to cut it, because it's clearly derived from Darwin observing finches."
Or worse yet, "Pi isn't going to cut it, because it's clearly derived from somebody taking a measuring string and measuring something circular"

No, no it isn't. Not inherently, not necessarily. These things can be independently arrived at by many means.
Observation can set us on the path to a Eureka moment, showing us something inherently logical that we just didn't figure out because of those things not being very intuitive to humans.
These concepts, beyond being logically valid and necessary, may be additionally (and unnecessarily) supported by empirical data.
They don't derive their authority strictly from empirical observation.

Assuming that we fully understand the quantum state and that there are absolutely no incoherences in the derivation of the MWI, we can say that it's true. But it's not yet clear whether those conditions are fully met.

It can be known to be true due to the process of elimination. There are no viable alternatives.

Would an ancient greek have been able to come up with special relativity? Sure, had/she he been genious enough to put all the signs together (possibly working with less observations than what was available later through technology, but still inducing ideas from observations) and develop all the concepts underlying SR on his own and then also derive SR.

You don't need any signs. You just need to question the concept of objective velocity on logical grounds. You create relativity by tearing down our seemingly intuitive (but wrong) assumptions, and building only what can be substantiated by logic.

What would he be trying to explain had there been no (observation of the) phenomena?

He wouldn't, that's the problem -- motivation. When we assume false intuition to be true (like deities), it stops us from exploring and trying to solve the real questions.

We only discover these things when observations destroy the holy temples of our false intuitions, because that's the only time we start thinking about them in different ways. BUT if you were to abandon those assumptions without the discovery (find the motivation to do so, despite the comfort of pretending to know), you could reason the same without any of the empirical data you assume to be necessary.

It's not that logic is dependent on empiricism, it's that the act of thought is dependent on confusion and removing the false assumptions of bad intuition, and conventionally, only observations have been strong enough to do that. When an argument against an irrational assumption is merely logical, it's easy for people to ignore or brush under the rug.

It’s a serious idea and it deserves serious discussion, however I don’t think that the case for MWI is a slam-dunk. I view it as a candidate for reality, but we haven't reached the point where we can move it from candidate to settled. Occam’s razor seems like a tough call on these interpretations.

What do you think the alternatives are, exactly?

Hidden variable? Whether god or quantum foam - you get the logical problem of infinite regress. Unacceptable. Next:

Copenhagen. You get dice, which is a serious philosophical problem of its own -- from whence comes chance? You also get the bizarre assumption of wave function collapse, which coupled with relativity paints an Earth-centric universe (which is its most obvious downfall). By what means can we assert that we are the center of the Universe? Where did that push-pin come from, that cemented the one true reality on us lowly humans? Another variable, with another lingering question demanding infinite regress.

MWI is all you have left. It wins by default. Not because it's proven true, but because every alternative is false.

I like your statement that MWI is the interpretation of QM with the least baggage, but I believe the ensemble interpretation might have even less baggage as it doesn’t assume the wavefunction ontologically represents any individual system, but instead the abstraction of that system. This seems more in-line with mathematics as a description and not fundamental in the universe. And the latter position might carry more baggage. I’m not sure of the answer, but dismissing the concern as silly seems unjustified.

Remember when we talked about accuracy and precision? This.
Ensemble is an "interpretation" that stops short of trying to really interpret the relevance of the mathematics to reality. It's a bit of a non-interpretation.

Wikipedia says it as well as I could:
http://en.wikipedia.org/wiki/Ensemble_interpretation

The ensemble interpretation, unlike many other interpretations of quantum mechanics, does not attempt to justify, or otherwise derive, or explain quantum mechanics from any deterministic process, or make any other statement about the real nature of quantum phenomena; it is simply a statement as to the manner of wave function interpretation.

It is not preferred by Occam's razor, because it's relaying an incomplete picture of what quantum mechanics mean. It's very nearly tautological.

The problem as I see it is that branches separate too fast and too chaotically for there to be that many consistent macroscopic objects at all. There might already be an explanation for this.

There aren't really "branches", it's just a wave function. A branching tree is just an easy way to explain it to a layman.

But more importantly, if probabilities can be meaningfully assigned to branches, then the theory is explanatory. But how can it make sense to talk of probabilities (other than 0 and 1) at all, since all 'possible' outcomes do (certainly!) occur?

Maybe you just explained/phrased this unclearly, but I'm getting the sense that you don't understand wave functions very well. Look into electron clouds to understand probability density better.

For sake of illustration, we'll assume that probabilities come in 10% increments (not true, and neither are "branches" exactly, but it's an easy way to illustrate).

That means that for event X, there are 10 "branches".
If something has a 50% probability, then it represents 5 of those branches. Something with 30% represents 3 branches. Something with 20% represents 2.

The number of universes for any outcome is proportional to its probability.

Assertions like 'the probability of spin-up will be 2/3' would be incoherent.

No, it's more like: "the probability of us being in a universe in which this is spin-up is 2/3"

I encourage you to read more on MWI.

The truth is we're not discussing new concepts here and we're probably not going to end this age-old epistemological debate.

Well, it really depends on how much stock you put in logic. If you're skeptical of logic, there's nothing that can be done about that, because you can't reason with a premise rejecting reason itself. If misunderstood you, and you accept logic, we can come to terms.

[knot]

Someone else in this thread has probably already pointed this out by now, but...

I really dislike the vegan/atheist labels because they shouldn't have to exist in the first place, and they make it sound like I'm something remarkable or strange. We don't have a word for someone who doesn't believe in astrology, or someone who is not a rapist or murderer. It'll prolly be a while before only the meat eaters will have to be labelled though

[brimstoneSalad]

It'll prolly be a while before only the meat eaters will have to be labelled though

That would be great. Like the word "cannibal".