Harv, "Sure he does". Harv, just because you say it doesn't make it true!
A very real issue exists here which you are totally failing to look at: the explainee's problem is to explain C (he has absolutely nothing else to work with)! It is an unstated assumption in any scientific work that the best explanation of C (the information you have to work with) is an explanation of A (the source of the elements which make up B the things you can test). Certainly there is no proof that A can be explained; what I am doing in my presentation is laying out a road map of the best we can possibly do (from a statistical perspective) given what we know (whatever that might be)!
When I do that, I discover that, no matter if the given information is utterly meaningless random drivel, I produce a mechanism which will yield expectations exactly conforming to that "meaningless random drivel". And, I don't care what the demon is providing (lies, truth, meaningless drivel or whatever), given any information to go on, your best bet is to expect to see patterns in the new information similar to what you have already seen. My model reproduces the statistical patterns in the information available and provides one with rational expectations (that makes it an explanation under the definition given).
Now to that point it is nothing more than an exact analysis of the statement: "the best bet you can make is that new information will be similar to what you have already been given". That is the only constraint I have imposed on my model. When I do that, I discover that arbitrary numerical labels attached to the references to the elements of B must obey my fundamental equation. If they don't, the statistical properties of the expectations will not conform to what was given.
Then, I discover that 90% of modern physics is nothing more than solutions to my fundamental equation (that's classical mechanics, electromagnetic phenomena, Dirac's work, nuclear forces, and both special and general relativity). To put it in another form: no physics experiment I am aware of can differentiate between a totally random universe and one with some rules. The only rule required to deduce physics we are aware of today is "the events making up the future will look very much like what we have already seen". You are aware of a collection of information which you have come label "a high speed vehicle headed for a lamp post" will most probably be found with a collection of information which you can label "a vehicle wrapped around a lamp post".
We are having great difficulty communicating. I believe some things are true and you believe some things are true; but the things you believe to be true don't exactly all map into the things I believe to be true. I put forth that the real problem between us is that you want me to explain in terms which you believe to be true.
I am asking you to believe five very specific things which I believe are correct. I only continue this conversation because I believe that you also believe these specific things are correct. Clearly, if you do not believe they are correct then we have no basis for communication.
So let's look at exactly what I am asking you to believe:
1) I am asking you to believe that mathematics is a logical structure: i.e., that any results of any mathematical deduction are as true as is the start position of the deduction. If you don't believe in that then you don't believe in the validity of mathematical deduction.
2) That there exists something to explain which we do not understand! I call it A. If you don't believe in A then you have nothing which needs explanation.
3) That there exists some information about A which is available to us. I call it C. If you don't believe in C then you have nothing on which to build an explanation of A.
4) That there exists some part of C which we can use to evaluate our explanation. I call it B. If you don't believe in B then you have no way to defend an explanation of A.
5) That there exists a way to refer to significant aspects of A, B, and C. If you believe there exist aspects of the problem which cannot be referred to, then I hold that you believe you cannot think about the problem.
Now, which one of those beliefs do you think is false? These are the only beliefs I ask of you. A lot less "faith" then you ask of me.