How much is needed to reasonably prove obviousness? In UCB, the majority found UCB, Inc.’s asserted claim nonobvious under non-statutory double patenting. The dissent, however, found overwhelming evidence in support of obviousness. The majority determined that prior art teaching was insufficient for a skilled artisan to have a reasonable expectation of success. To the dissent, however, the majority’s analysis was flawed because it ignored the fact that the law required only a reasonable expectation of success, not a guarantee. One might say the majority viewed the glass as half full and the dissent half empty.