In programming terms the tangible are the concrete things... the code on the screen in tangible, but when you start inferring meaning, concepts, origin, relationships etc in your head (or the reverse - doing that before you write some code) - that stuff is the quantum probability field that you need piece and quiet for, when that guy comes and asks you a question it collapses and you start over - if your very lucky you might get some state back and it wont take quite as long.
But here's the thing... the more complex the problem the longer you need to stay in that state - building it up larger and then refining it and so on, and the more important quiet becomes. Sometimes I don't mind noise if i'm just hoping from one "tangible" bit of code to the next doing some fairly mindless debugging that doesn't take a whole lot of insight, but most of the time i'm not.
But it's hard we all need to communicate eventually, constant meetings are no good, I find the best thing is this new instant messenger trend... not because I like being pestered but because I can turn off the notifications and then go and check it when i'm done on my current chunk of thinking.