The second problem with Dawkin's statement is that it's not true. Not remotely. An actual scientist wouldn't try to pretend that 'science will one day prove or observe something' which isn't currently proven or observed. Dawkins isn't acting as a scientist when he claims this stuff, but as a polemicist.It appears to be Krauss' statement, not Dawkin's, but your point still holds. Setting aside experimental evidence, I haven't even heard of a scientific hypothesis put forward of something coming from truly nothing. His "nothing" is not really nothing, although his argument may be.
Double negative correct!
Scientists know that "something" observations might lead to proving something that isn't currently proven or observed.