Dr. Craig is a liar.

[The Grand Nudger]

For instance virtual particles have not been directly observed, but there is reasons to believe that they exist.   I haven't experienced these reasons, but I can rely on the testimony of multiple independent people to convey their experiences.   I can also look at those who contest it, and their reasons. I can look at the assumptions and reasons, and see if the conclusion follows.    I don't think, that we needed to understand gravity, before we said that gravity existed.   We had reason to believe it, before understanding it.  However if the claim is why x occurs, then this is a claim of understanding, and we need to explain why that or give reason for that claim.

Purportedly, those people on either side of the issue understand what it is they're talking about, we wouldn't refer to them without confidence in that, and have managed to convey that understanding to you.....or what, again, are we talking about?

You haven't described any situation in which something depends upon what is being claimed...you've simply re-iterated the necessity of understanding to any claim or consideration of a claim.  

Not that any of this matters..because we're not talking, when we talk about god-belief.....about something that scientists do in labs and then report on for verification..are we?  Why would the analogy apply? How is it supposed to be informative?