What does the BGV theorem say?

[Jim]

@PdotdQ

For example, when the New Horizon team took this beautiful picture of Pluto , all that is directly detected are voltages on CCD chips (the same things that are in your phone cameras). Then, they need to use quantum mechanics to interpret these voltage readings to make the picture. In this case, is Pluto directly or indirectly observed? For more information on this problem in general, you can take a look at the Duhem-Quine thesis .

Not sure directly observed or indirectly observed would be so necessary to distinguish. I guess I kind of slipped that term in there in my explanation in my previous comment kind of unknowingly. I would say, however, another distinction could be made between unaided observation and instrumentally aided observation.

The former would generally be the more reliable, and the latter would have degrees of reliability depending on the type of instrumentation and how well it can be objectively confirmed. There should also be a distinction with detection methods as well regarding degrees of reliability.

@PdotdQ

Correct, we should be neutral to “whether or not these facts could be overturned by subjective inferences”.

First, there are no such thing as scientific facts that cannot in principle be overthrown, even for those in the “highest degree of certainty”. After all, classical mechanics was thought to be in “highest degree of certainty” once.

Second, again you are a priori ranking “subjective inferences” as worst than “direct inferences”. This is not true in general. Every scientific inference has an error bar. What you might call “direct inference” will have an error bar from its observational errors. In the sciences, logical inferences flow mathematically from a theoretical foundation which are empirically confirmed, again with observations that have their own error bars. If there is evidence where the logical inference contradicts the direct inference, these two error bars have to “fight it out” to see which come out on top. I am not sure how else to explain Bayesian inference aside from this.

OK. But my first question is, what is meant by direct inference? Would the meaning of a direct inference include an objectively confirmed unaided empirical observation as being a direct inference? Next, has any objectively confirmed unaided observation ever been overturned? And if so by what was it overturned? And certainly it seems in making a probability judgment an unaided objectively confirmed observation would be higher than a subjective inference.

And then in relation I would imagine the scale would go down for objectively confirmed instrumental observations relative to the degree of decreased reliability of the instrumentation. Detection would be similar although more limited in what is revealed by it than the latter.

And as for classical mechanics, it’s not clear to me whether or not you’re including GTR and STR here. You seemed to be including them in one of your previous comments. If you don’t include them, then as I understand it, there were only certain specific aspect of CM that needed to be changed. The rest still stands. Is that correct?

If so, I might somewhat agree with your point here with some qualification. However, as I mentioned in a previous comment, I’m mainly interested in empirical scientific facts, not so much objectively confirmed abstract theories and formulas.

@PdotdQ

I think one should not even quote the BGV theorem. The problem is that I am not convinced that the BGV theorem is strong enough to warrant inclusion in this list of “comprehensive argument”.

Is it possible to make the case of a beginning without the BGV? Well, I would say it would be a significantly weaker argument. But speaking as a layperson, I think I still have to beg to differ with your assessment of BGV.

From what I’ve seen I think that it is sufficiently strong enough to be included. I think we disagree on certain subjective aspects in regards to how strong it is which, based on evidence and other factors presented to me, I believe I’m warranted to take an alternative position on. I think if you factor my position on those subjective aspects into it, there’s enough reason to rate it’s strength as at least sufficient, if not more than.

And since Bayesian inference, like all other inferences, is subjective in nature, I don’t see any problem coming to different conclusions based on the subjective aspects involved in each of our positions. And I think that since other scientists and scholars seem to differ with your assessment as well, it seems I’m at least be within the bounds of reason.

@PdotdQ

First, just because we have not been clever enough to find a model that “does nothing ‘forever’”, does not mean that it is not true.

Well, I think what he was talking about is a model that can account for both being past eternal and evolving 13.8 billion years ago. That’s quite different than one that does only one or the other.

@PdotdQ

Second, no one claims that the quantum Universe will “[do] nothing ‘forever’” or “does not evolve”. It might, for example, oscillate or balloon back out in the negative time direction.

Again, I don’t think this is what’s being claimed by Craig. I think what he’s saying is, if quantum indeterminacy is assumed and going only by what is known in the objective sense at present, including the age of the universe, under those circumstances the only way a quantum regime could be without a beginning is if it did nothing from eternity past until 13.8 billion years ago, at which time it evolved into the universe.

So what he seems to be saying is, a quantum regime model would need to be formulated based on both of those conditions being met, i.e., past eternal doing nothing, and suddenly, at the initial physical event 13.8 b years ago, go from doing nothing to evolving into the universe. In his estimation, that would seem to be the only option available.