Gedanken
Gedanken
(1)gedanken
(2)"Gedanken" is a German word for "thought". A thoughtexperiment is one you carry out in your head. In physics, theterm "gedanken experiment" is used to refer to an experimentthat is impractical to carry out, but useful to considerbecause it can be reasoned about theoretically. (A classicgedanken experiment of relativity theory involves thinkingabout a man in an elevator accelerating through space.)Gedanken experiments are very useful in physics, but must beused with care. It's too easy to idealise away some importantaspect of the real world in constructing the "apparatus".
Among hackers, accordingly, the word has a pejorativeconnotation. It is typically used of a project, especiallyone in artificial intelligence research, that is written up ingrand detail (typically as a Ph.D. thesis) without ever beingimplemented to any great extent. Such a project is usuallyperpetrated by people who aren't very good hackers or findprogramming distasteful or are just in a hurry. A "gedankenthesis" is usually marked by an obvious lack of intuitionabout what is programmable and what is not, and about whatdoes and does not constitute a clear specification of analgorithm. See also AI-complete, DWIM.