When you have exhausted all possibilities, remember this: you haven't.

We searched Edison's documented corpus for this line — including his correspondence, notebooks, patents, published interviews, and the archival holdings of the Thomas A. Edison Papers project at Rutgers — and found no primary source containing "When you have exhausted all possibilities, remember this: you haven't." The sentiment fits Edison's well-known perseverance and his "10,000 ways that won't work" reputation, which is very likely why the line attaches so readily to his name, but thematic resonance is not authorship. The prior investigation of this saying found no substantive support for Edison and traced its circulation to late-20th-century motivational usage, well after his 1931 death. A live scan of published books confirms the phrase appears widely — credited to Edison in works such as T.C. Hale's "Health Pro Results" (2018) and Jo Toye's "Abstract Explorations in Acrylic Painting" (2016) — but these are recent motivational and how-to titles that supply no primary citation and merely echo the common attribution. We also encountered occasional credits to Robert H. Schuller, but that alternative is itself unsourced, so no stronger competing origin can be responsibly named, and none of these appearances predates Edison. With no primary Edison source, no documented earlier instance, and no credible named alternative author, this line is best described as attributed.