Earlier quoted context omitted.
> They don't actually understand what these concepts mean. You say this so confidently. But can you define in terms that are directly quantifiable what "understanding a concept" actually means? I don't believe that anyone can (at present, anyway) although there are certainly some interesting theories and heuristics that have been put forward by various people.
>> You say this so confidently. But can you define in terms that are directly quantifiable what "understanding a concept" actually means? Hold on there, can you "define in terms that are directly quantifiable what" 'God is real' "actually means"? If you can't, does that mean that atheists, like me, can't continue to say very confidently indeed that he doesn't? Do I, as an atheist, need to provide proof of God's non-e…
I was not saying that.
> why is it skeptics that have to provide evidence that they don't?
Because if a claim is going to be made in either direction then evidence or other reasoning to support it should be provided. My position is that the "sensible" default position in this case is one of "we don't know". Of course defaults are always some degree of subjective in that such judgments ultimately arise from our personal worldview.
Before you object that this is an unreasonable default in this case, consider that I can't even prove that other people are sentient. I can't articulate in quantifiable terms what exactly it means for a person to understand a concept. So if I accept that the default is "not sentient until proven otherwise" then there would seem to be an issue. I would then simultaneously be saying that other _people_ aren't sentient (I can't prove they are) and that other _people_ don't understand things (I don't even know how to measure such a thing, after all).
> If you can't, does that mean that atheists, like me, can't continue to say very confidently indeed that he doesn't?
I'm not quite sure I follow. Indeed I hold that strong claims that God either does or does not exist are unreasonable on the basis that both would appear to be fundamentally untestable claims. At least, untestable short of such an entity choosing to provide incontrovertible proof of its existence.