People need to be more careful when using the term "backing" when referring to money. It has a very specific meaning but is usually perverted and causes lots of confusion.
"Backing" means that a party guarantees to exchange one asset for another upon redemption at a fixed rate. In the case of gold-backed USD, the banks guaranteed to give you gold in redemption for the paper, and this was at a fixed rate. Thus, the dollar was "backed" by gold. That's what backing means - a counterparty specifically promising to exchange one for the other at a certain rate.
Thus, Bitcoin is not backed by anything. Nor is gold backed by anything. Nor are dollars today backed by anything.
It is wrong to say that Bitcoin is "backed" by electricity, or cryptography, or the size of the Bitcoin economy. It is similarly wrong to say the USD is backed by the government, or by violence, etc. To do so is to pervert the term. Bitcoin is not backed by anything, and that is just fine, because it's a commodity unto itself and is valuable for its specific attributes. It needs no "backing" - it is a thing unto itself which we value. Same for gold.
If you find yourself in the position of saying Bitcoin is backed by something, change the term to say "Bitcoin is valuable because..." Or, "the USD is valuable because..." The answer to those sentences will be valid, and you won't be caught in the misnomer of "backing."
Yes... 'but'... or 'and'... instead of getting into narrow technical definitions of the words people use in their questions and concerns, about something like
bitcoin, it is perhaps best to get to the essence of what they are looking for. Confidence in the value of something. When someone wonders if bitcoin
is backed by something they are really wondering that if they get some today, will it have value tomorrow. Can they use it to buy things and services
that they need? Do they have the support of their society to use it in the ways they have to come to rely on with other currencies they use?
With dollars even though you say it isn't technically backed by anything it is taken by, for example, utility companies so one can pay to heat their
homes. And while one may say that there are no guarantees that anyone should accept this or that currency in exchange for their goods or
services that utility company would need a good reason to refuse to accept dollars from someone looking to pay their heating bill. There would be
legal recourse, and if the utility company didn't want to follow the courts decisions they would have to face government law enforcement. And so
I don't see that it is entirely wrong to say that dollars are backed by the Government... by society. This gives many, if not most, people confidence
( a misplaced confidence perhaps but important to them just the same ), and so it these types of concerns of average ( non-techie ) people that
we want to address.
To say that bitcoin is backed by math and cryptography ( and robust networks etc. ) is, in a way, of saying that there 'are' laws that one can have
confidence in. A different kind of law that doesn't need to be interpreted by lawyers and judges, but rather mathematical axioms etc., that are
politically neutral and beyond manipulation and coercion. 2 + 2 will still = 4 even if you point a gun at their heads.
But of course that doesn't make it easier to instill confidence in non-techie people. While they may have a reasonable confidence that they can
use their dollars and they will be backed-up by the rules and laws of the society they live in they may not be as comfortable trusting, what they
may see as, a bunch of nerds or hackers and the incomprehensible math and science they play with in their dark basements.
I am not sure what is the best way forward. Educate people to help them understand and learn to trust the bitcoin protocol/network? Show them
how existing systems are untrustworthy? Of course it isn't an either/or equation and many approaches can be used at the same time... including
individuals and groups helping to build and nurture a new type of fair, sharing and caring society...
"Remember, I'm pulling for you. We're all in this together." - Red Green