[excursionist]

I think the main difference between the Engelbart work you cite and Turing, for example, is the ambiguity of their ideas. It's a lot easier to come up with some futuristic idea about _what_ is being done, then a specification of _how_ that futuristic thing is done. There are so many interesting ideas that can be found in science fiction (and many of them end up being implemented decades later), but they are not very useful without the knowledge of how to actually build these things.