Ketubot, Chapter Two, Mishnah Ten
The entire first two chapters of Ketubot have dealt with the issue of believability in the absence of evidence or two witnesses. Our mishnah discusses in which situations a person is believed to testify about things he saw when he was a minor. That is to say, although minors are not allowed to testify, there are certain things that a minor can see about which he may testify upon reaching adulthood.
The following are believed to testifying when they are grown-up about what they saw when they were minors:
1) A person is believed to say This is the handwriting of my father, This is the handwriting of my teacher, This is the handwriting of my brother;
2) I remember that that woman went out with a hinuma and an uncovered head;
3) That that man used to go out from school to immerse in order to eat terumah;
4) That he used to take a share with us at the threshing floor;
5) That this place was a bet ha-peras;
6) That up to here we used to go on Shabbat;
7) But a man is not believed when he says: So-and-so had a path in this place;
a) That man had a place of standing up and eulogy in this place.
Section one: A person is believed to say that the signature on a document is similar to the handwriting of a person with whom they were close in childhood. The assumption is that a person would remember this well. Furthermore, this is not really testifying but just verifying someone elses testimony, and therefore there is more room to be lenient in accepting such testimony.
Section two: A person is believed to say that he was at a wedding and the bride wore the signs of a virgin (see mishnah one of this chapter). The Talmud explains that he is believed because most marriages are first marriages.
Section three: A priest must immerse before he eats terumah. The time of immersion is right before evening. A person is believed to say that he saw one of his classmates leave school early to immerse in the mikveh, and that hence he is a priest.
Section four: The priests collect their terumah at the threshing floor. By this person testifying that so-and-so collected terumah, he is saying that he is a priest. Note that again the mishnah is concerned with verifying the status of priests.
Section five: A bet ha-peras is a field adjacent to a field that used to serve as a cemetery but has been plowed over. The adjacent field may have small pieces of bones there, and therefore a priest may not enter. A person is believed to identify such a field, even if he only saw it in his childhood.
Section six: On Shabbat a person may leave his town only 2000 amot. This is called the tehum shabbat or shabbat limit. A person is believed when he reaches majority age to say that when they were children they would go this far out of the city. The reason he is believed is that this is a matter that can be verified.
Section seven: The mishnah lists two things a person cannot testify that he saw as a minor. First of all he may not testify that a certain person owned a path through someone elses field. Second of all, he may not testify that a person owned a place where they used to stand and give eulogies. Such places were owned on the paths that lead from the cemeteries to the cities. It would have been like a small, private funeral home. In both of these cases, the testimony involves the ownership of land. For a person to prove that he owns a piece of land, he will need to bring firmer testimony than this.