I'm learning Bava Metzia 21b in daf yomi. Rashi and Tosafot seem to read the same case in opposite directions. Am I missing something, or is this a real disagreement?
You are not missing anything — this is a real disagreement, and it turns on what despair of recovery means. Rashi reads it as a state of mind the owner has already reached; Tosafot read it as one the law assumes he will reach…
See also: Bava Metzia 22b, and the Rosh there.