William Lane Craig and the BGV

[WalterP]

DISCLAIMER

 

This thread will be tightly focused on the way the Christian apologist William Lane Craig uses this scientific paper ( https://arxiv.org/abs/gr-qc/0110012   Inflationary spacetimes are not past complete) to argue that even past-eternal inflationary models must have had a definite beginning.  The way he does this causes him to inadvertently argue FOR the existence of an inflationary multiverse - something that he strenuously denies elsewhere in his apologetic ministry, on his own website, Reasonablefaith.com.

 

If you aren't familiar with the issues described above please note that I won't be explaining them in this thread.  What is under discussion here is something only for those members with (A) a good working knowledge of Craig's apologetics and (B) a good working knowledge of cosmology.  If you lack either of these things then I'm sorry, I do believe that you shouldn't participate in this thread.  Thank you for your attention and cooperation.

 

WalterP.

 

 

[WalterP]

Hello.

 

The key to understanding how William Lane Craig trips himself up with the Borde-Guth-Vilenkin paper, is to remember how the Copernican Principle must be applied to the portion of the universe that we can observe - what is known as the observable universe.

 

https://en.wikipedia.org/wiki/Copernican_principle

 

"In physical cosmology, the Copernican principle states that humans, on the Earth or in the Solar System, are not privileged observers of the universe.[1]

Named for Copernican heliocentrism, it is a working assumption that arises from a modified cosmological extension of Copernicus's argument of a moving Earth.[2] In some sense, it is equivalent to the mediocrity principle."

 

According to Craig, any and all models of Multiversal cosmology are flawed and unrealistic because none of the regions beyond the limits of the observable universe are NOT accessible to us.  That which is not accessible to investigation by science cannot be considered to be 'properly scientific' and therefore any theory that posits their existence is just speculation, not proper science.  So, even the simplest inflationary models that posit an unbroken extension of our universe beyond the visual limits of observation are ruled out by this measure.  Craig's entire universe ends abruptly at the visual horizon.

 

He argues vigorously and at length on his Reasonablefaith website against the existence of any kind of Multiverse, inflationary or otherwise. His religious beliefs oblige him to do so because his prime aim as a Christian apologist is to bring science into alignment with the Bible, specifically Genesis 1:1, where scripture declares that all things had an absolute and definite beginning.  

 

This means that the workings of any theory of physical reality which Craig uses in his apologetic arguments must be confined within our observable universe.  Therefore, when he uses the findings of the Borde-Guth-Vilenkin theory (hereafter, BGV) to argue that even a past-eternal model of inflation must have had a beginning, he is obliged to place that starting point within our observable universe, 13.72 billion years ago.    

 

Craig has no choice but to do this.  If he were to concede that the starting point happened at any time prior to our Big Bang, then he would be conceding the existence of other 'universes' before and beyond ours.  For him all of time and space began with our Big Bang, which birthed only our observable universe.  He will not concede the existence of any time or space prior to that which we can observe.  Doing this would contradict Genesis 1:1.

 

Now let us examine how his take on the BGV sits with the Copernican Principle.

 

He points out that even the BGV must have had a point of origin, a definite beginning.  But his faith requires him to do what cosmologists do not - to make that origin observable to us.  Cosmologists do not do that because that would mean violating the Copernican Principle.  If our Big Bang was the starting point of an inflationary process that went on to generate other universes, then we would be in a privileged position relative to those other universes.  We could observe the ultimate beginning, but other observers in any other observers could not.

 

That would make us privileged observers of the absolute beginning of everything -  in clear violation of the Copernican Principle.

 

The principle requires that ALL observers be accorded the same status.  Borde, Guth and Vilenkin concede that the beginning of the past-eternal inflationary process must have begun somewhere, but they correctly refrain from saying exactly where this is.  They also refrain from saying who could have observed it.  Craig, however does not refrain.   He asserts that we are observers of that absolute beginning because our observable universe is all that there is.

 

However...

 

If Craig were to toe the line and abide by the Copernican Principle, then he would be obliged to concede the existence of universes 'before' ours.  This would be an admission of the existence of a Multiverse, putting him in complete contradiction of his stated position in Reasonablefaith.com, that a multiverse does not exist. So, when it comes to the BGV Craig is impaled on the horns of a dilemma.

 

If he denies any and all Multiverses, he makes us observers of the absolute beginning of the entire Multiverse, violating the Copernican Principle.

 

If he argues that the BGV has a definite beginning, but we are not observers of it, then he concedes that other universes prior to ours must exist, contradicting himself.

 

Thank you.

 

Walter.

 

 

 

Edit.

(Just noticed that I wrote that... regions beyond the limits of the observable universe are accessible to us. Typo!  NOT accessible.  Sorry for any confusion caused and the body of my post has now been corrected.)

 

[Joshpantera]

9 hours ago, WalterP said:

If he denies any and all Multiverses, he makes us observers of the absolute beginning of the entire Multiverse, violating the Copernican Principle.

 

If he argues that the BGV has a definite beginning, but we are not observers of it, then he concedes that other universes prior to ours must exist, contradicting himself.

 

When you start off on the wrong foot, it seldom gets better as you go along. In fact, it tends to gets worse and worse. Craig is little more than a Ken Ham with more credentials and philosophical training to bluff with. But that's all Craig is, a bluff. And a very deluded bluff at that.