In philosophy, the Goethendipity principle states that if you have a plan or a dream, you must act on it. You must resolve yourself to carry it out. Once that resolve has been taken, events will move in your favor. It is serendipity with plan, vision, and intention. The principle was conceived in the early 1990s by English accelerated learning expert Tony Buzan who, on a trip to Africa, was invited to speak on the development of genius on a radio show, and to explain to his interviewer that it was not ‘luck’ or serendipity that had brought the two of them together, but Goethendipity that had brought them together, a term themed on the following quotation by German polymath Johann Goethe: [1]

“Until one is committed there is always hesitancy, a chance to draw back. Always ineffectiveness concerning all acts of initiative and creation. There is one elementary truth—the ignorance of which kills countless ideas and splendid plans—that the moment one definitely commits oneself, then providence moves too. All sorts of things occur to help one, that would never otherwise have occurred. A whole stream of events issues from the decision, raising in one’s favor all manner of unforeseen incidents and material assistance, which no man could have dreamed would have come this way. Whatever you can do or dream you can do, begin it. Boldness has genius, power and magic in it, begin it now.”

– Goethe, Faust (1832)

The passage comes from part two of Goethe’s Faust. [2]

Buffett
Another version of the same principle seems to be found in American business mogul Warren Buffett's favorite book One Thousand Ways to Make $1,000 dollars, that he read as a youth—the central advice of which was to "begin, begin" whatever scheme one might, but, by all means, not to wait. [3]

References
1. Buzan, Tony and Keene, Raymond. (1994). Buzan’s Book of Genius (pgs. 45, 164). Stanley Paul.
2. (a) Goethe (popular quotes): Commitment – Goethe Society of North America.
(b) Goethe’s Faust – Wikipedia.
3. Lowenstein, Roger. (1995). Buffett: the Making of an American Capitalist (pg. 16). Broadway.

External links
● Goethendipity principle (Dutch → English) – JWGoethe.org.