They inquired: Did Rabbi Shimon ben Elozar state his halachah (that one may keep a lost object when he finds it in any place where many people are commonly found) only in a place where the majority of the people are Canaanites (for one is not obligated to return a Canaanite’s lost object, and even if it belongs to a Jew, he would have given up hope of recovering it), or did he state his halachah even in a place where the majority of the people are Jews?
Tosfos explains that since it was found in a place where there are many people, there are certainly dishonest people amongst them who will not be concerned about the mitzvah of returning a lost article; therefore, the owner will despair of recovering it.
The Raavad explains that it is because the minority of Canaanites that reside in the area are regarded as significant, and we may assume that it fell from them. And even if it fell from a Jew, the Jew will despair from recovering it, for he will assume that a Canaanite will find it and keep it for himself.
Tosfos asks: Why are these reasons necessary? Could we not apply the principle that we do not follow the majority with respect to monetary law? Let the finder say that perhaps it fell from a Canaanite, and it cannot be taken away from him, for he is a muchzak (he is presently holding it, and there is no proof against him)!?
Tosfos answers that this principle only applies in cases where the money came into his hands with permission; however, in our case, the owner had no knowledge that it entered his possession – the finder’s chazakah is not stronger than the majority.