Study Bava Kamma folio 75A with parallel Hebrew-English text, traditional commentary, and modern study tools. Free access to Babylonian Talmud online.
The Talmud answers: Nevertheless, R' Yehoshua was not present in court when Rabban Gamliel encountered him.
The Talmud asks a question from a different source: But isn’t it taught in a baraita that R' Yehoshua said to Rabban Gamliel: Your statement is nothing, as you have already admitted to inflicting the injury yourself? This indicates that even if witnesses would subsequently testify about the injury,
The Talmud suggests: What, is it not the case that the difference between these two baraitot is a dispute between tanna’im? This tanna of the first baraita, who says that R' Yehoshua’s statement was: As you have no witnesses, holds that one who admits that he is liable to pay a fine is liable to pay
The Talmud rejects this suggestion: No; it is possible to understand the baraitot differently. Everyone agrees that one who admits he is liable to pay a fine is exempt, even if afterward witnesses come and testify to his liability. And they disagree with regard to the following: This tanna, who sa
The Talmud analyzes in detail the dispute alluded to above: It was stated with regard to one who admits that he is liable to pay a fine, and afterward witnesses come and testify to his liability, that Rav says he is exempt, and Shmuel says he is liable.