Daneel considers this, even as he approaches a likely looking bookshelf. He's not convinced that quantum mechanics can really apply in investigative situations.

"I'm not sure that this logically follows," he says, cautious about offering a contradiction. "While I do not doubt that truth can be found by investigating apparently inconsequential details -- and indeed, I have seen partner Elijah come to the truth of something by focusing upon a fact that would seem to be irrelevant -- that does not mean that any tangent will lead to a productive solution. How do you determine which tangent is worth following?"