If you are in it you can't see where you are heading.  But you have to move forward.  So you do something to find out what lies ahead.  Could be a SpikeSolution, a prototype, and increment, depending on your knowledge and bravery.

A project management pattern written up in AlistairCockburn's ever-so-imminent Surviving OO Projects book, and excerpted on his web page http://members.aol.com/acockburn/riskcata/riskbook.htm as well as Jim Coplien's Organizational Patterns page, 
http://www.bell-labs.com/cgi-user/OrgPatterns/OrgPatterns?ClearTheFog

--- AlistairCockburn