What does the BGV theorem say?

[PdotdQ]

@Jim

I think you may be the first scientist I’ve come to realize doesn’t subscribe to MN. I’ve even dialogued with a YEC scientist, and an OEC scientist and they both defended MN in the context of doing science.

The atheist (militant?) Sean Carroll does not seem to subscribe to MN (Dump the Metaphysics — How About Methodological Regularism? - #3 by Patrick)

@Jim

E.g., the existence of Pluto is an established fact, i.e., objectively confirmed through multiple direct observations using a telescope. There may need to be more distinction made here, but that’s the general gist of it.

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.

@Jim

I’m not sure I understand what you’re saying. I’m mainly concerned with established scientific facts and confirmed human experience which would mean the highest degree of certainty. Are you saying that we should be neutral to whether or not these facts could be overturned by subjective inferences?

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.

@Jim

I’m not quite sure I follow you here. I think you’re saying that in light of my prior assumptions, based on the evidence I’ve already considered, though BGV would add additional weight to support my conclusion, it wouldn’t significantly affect it. Is that correct?

Not only it might not significantly affect it, I am not even sure that it affects it at all.

@dga471

I think that in general, scientists would be less disturbed if you supported the comprehensive argument of C&S

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”. In this case, adding it into the arguments is just a Gish Gallop. It’s like saying “I believe that most Chinese people speak English”, because:

A) I did a survey of X Chinese people and found that Y% speak English
B) Oh, and also, most Americans speak English

Just use A) to argue and drop B).

@Jim

It is very difficult to devise a system – especially a quantum one – that does nothing ‘forever,’ then evolves. A truly stationary or periodic quantum state, which would last forever, would never evolve, whereas one with any instability will not endure for an indefinite time. [15]

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.

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.

Third, this argument does not use the BGV theorem, which is the “evidence” under contention in this thread. Like I said, if you have better evidence that the Universe has a beginning, use that instead of the BGV theorem, unless you are interested in doing a Gish Gallop.

@Rumraket

Just dropping in to point out that there’s a difference between saying the universe had a first moment of time(it’s beginning), and saying the universe literally came into existence where before it didn’t even exist.

This is a good point. The beginning of time might be explained by physics, for example, in the quantum gravity models in which time itself is emergent and appears from some sort of “quantum soup”. However, this just pushes back the problem: how did this “quantum soup” exist?