Impermissible hindsight

Note the text within Ex parte Budinkski :

While Yan does teach and claim that the decal material may be porous and/or non-porous as found by the Examiner (Ans. 9), we fail to see how such disclosure would have suggested forming a non-porous decal-electrode layer-porous decal structure as required by the claims absent impermissible hindsight reasoning. Rather, within the context of Yan such a disclosure reasonably means that porous and non-porous decals may be used to form different, individual electrode layers for attachment to a fuel cell membrane. Yan teaches that the multiple electrode layers with different ionomer gradients may be formed and transferred to a membrane with the different layers adjacent one another to form a particular ionomer gradient in the fuel cell (see, e.g., Yan, para. [0091]).
On this record, the Examiner has not established that the prior art would have suggested the proposed modification to Yan to arrive at the claimed non-porous-electrode material-porous decal structure. Rather, we agree with Appellant that the proposed modification of Yan is based on impermissible hindsight.