Carrying on from the previous post…
Though we can't simply dismiss Carl Sagan's universe-architects in Contact by saying 'a π is a π is a π,' it's still true that the task of creating a universe is inconceivable, given that we hardly understand what our universe is and how it came into being. Another inconceivable endeavour is the building of a Dyson sphere—a structure completely enclosing a star so as to capture all its radiation on the inner surface.
But of course as soon as 'inconceivable' is aired, someone's going to bring up that Princess Bride quote: "You keep using that word. I do not think it means what you think it means."
Is it possible to build a Dyson sphere? Less than a hundred years ago, it would have been inconceivable to build the International Space Station (ISS). Go back another few centuries and the Three Gorges Dam would be inconceivable. Prehistoric man would doubtlessly have regarded the Great Wall of China as a feature of the landscape, unable to believe it had been shaped by human hands.
Superficially this is an issue of technology, but another aspect is intriguing: the non-technical resources required for these 'inconceivable' projects. This dovetails neatly with one theme of a Leadership course I'm taking this term; that engineers increasingly require leadership qualities and become useless without them as the world shrinks.
Major engineering efforts are also major leadership challenges. Examining the ISS or Three Gorges, the sheer number of people involved both directly and in support (mining and refining raw materials, fabricating parts, feeding and clothing the workers, etc.) is as stunning as the products. Many large projects rely on existing structures to get their immense workforces moving in the same direction, but this isn't always possible.
Take for example the new Airbus A380, an aircraft so huge one might say it's inconceivable that it could ever leave the ground. It's been hampered by years of delays, not because it is technically infeasible, but simply because there was no existing human structure necessary to engineer a redundant and multiply-failsafe electrical system containing over 500 km of wire. Creating such a thing for the first time was bound to be problematic. The ISS has been threatened by the variable political will behind some of its member agencies. These are not issues of technology, but of its application.
Returning to Dyson spheres, consider the scale of such an enterprise. It's probable that there are not enough people (or engineers) now living to complete such a project in a millenium, even if the technology were available. Assuming (very generously) that humanity continues to grow without eliminating itself, and manages to free itself from the Earth before the heat death of the Sun, we can hypothesize that the necessary technology would, in time, become available. Complete stagnation in the sciences would probably coincide with the failure of the species.
Then wondrously consider: what sort of human structures would be required to build Dyson's sphere? How would billions of people be motivated to work on a project that might span even an extended human lifetime? To speculate on such questions is the purview of some very interesting fiction, including Frank Herbert's Dune series that I return to again and again. Religion seems to be a likely candidate structure, and that's where I ended my train of thought: it is inconceivable that 'engineering' could entail fashioning entire religions simply to ensure a project is completed.