"It is the patentability standard of obviousness—the legal framework upon which courts and the Patent Office interpret whether the proposed invention would have been obvious to a person of ordinary skill in the art—that controls this balance. The difficulty for courts in determining obviousness, and thus patentability, is hindsight bias. When someone already knows how an invention works it is all too easy to consider it obvious, yet before learning about the invention, the same person would not have been able to envision the invention."
(Scott R. Conley, Irrational Behavior, Hindsight, and Patentability: Balancing the "Obvious to Try" Test with Unexpected Results, IDEA Vol. 51 No.2)