From the Book:

Minimum Viable Strategy allows organizations to test strategic hypothesis without betting the house on a strategy that may or may not work.  It is the relentless pursuit of “two-way door decisions” with the benefit of staving off one-way door decisions as long as possible until the fog has cleared enough to make a substantial investment in a particular direction based on real-world experience, feedback, and data.  This avoids strategy formulation in an Ivory Tower and brings it closer to the real-world operations of day-to-day business.