It seems from the words of the Gemara that the reason the person is Chayav
is due *not* to the Ed Echad's testimony, but due to his own admission.
Abaye, though, is telling us that the *Ed Echad* is believed! How is Abaye's
statement to be reconciled with the words of the Gemara (in its
"Tzerichusos")?
Moreover, the Gemara then cites a Machlokes between Rava and Abaye. Abaye
maintains that the testimony of an Ed Echad can be used even for a "Davar
she'b'Ervah;" the single witness may testify that a man's wife committed
adultery. Rava argues and maintains that "Ein Davar she'b'Ervah Pachos
mi'Shenayim" (a matter of a prohibited relationship requires at least two
witnesses). If Abaye's reasoning for why an Ed Echad is believed is because
of the admission, Hoda'ah, of the other party, then what is Rava saying?
Abaye is discussing Hoda'ah, while Rava is not addressing the issue of
Hoda'ah at all! Perhaps Abaye agrees with Rava that "Ein Davar she'b'Ervah
Pachos mi'Shenayim" in normal cases, but in a case where there is Hoda'ah,
we do not need any testimony at all! In addition, why should Rava argue with
Abaye, since, in this case, testimony is not necessary?
1. RABEINU TAM concludes that our Sugya is not teaching anything about
accepting the testimony of an Ed Echad, but rather it is teaching that
"Shetikah k'Hoda'ah" -- silence on behalf of the defendant is considered as
admission to the claim against him.
2. The RITVA and most other Rishonim maintain that our Sugya is discussing
the acceptance of the testimony of an Ed Echad.
3. TOSFOS (DH Rava) and the RAN maintain that the two concepts are, in some
way, intertwined, such that the testimony of the single witness and the
Hoda'ah of the defendant work simultaneously.
(a) RABEINU TAM. While the "Tzerichusos" of the Gemara imply that the issue
of the Gemara is whether or not "Shetikah k'Hoda'ah," as Rabeinu Tam
maintains, why, though, is it necessary to have the defendant's Hoda'ah? The
testimony of an Ed Echad is believe with regard to Isurim, so why should his
testimony not suffice, even without Hoda'ah?
TOSFOS (65b, DH Nitme'u) quotes the Gemara in Gitin (54b) which describes a
case of a person who is working with someone else's food products, who
testifies that those foods became Tamei. The Gemara there states that a
person is not always believed in such a situation. If he is presently
working with the food, then he is believed. If he is no longer working with
the food but has finished all of the work on it and handed it over to the
owner, he is not believed. The reason he is believed while he is still
working with the food is because it is "b'Yado," in his ability, to make the
food Tamei, and thus he is believed when he says that the food became Tamei.
Rabeinu Tam concludes, based on the Gemara in Gitin, that the testimony of
an Ed Echad is fundamentally different that the testimony of two Edim. When
two Edim testify, we accept whatever they say due to their trustworthiness.
A single witness, in contrast, is not believed due to his trustworthiness
(in cases of Isurim, where his testimony is accepted), but rather he is
believed based on the logic of "b'Yado." Without "b'Yado," his testimony
would not be accepted.
Rabeinu Tam explains, therefore, that since there is no element of "b'Yado"
in any of the cases mentioned in our Sugya (it is not within the Ed's
ability to make the other person eat Chelev, or to be Metamei the other
person's Taharos, or to make the other person's ox a Nirva), it is necessary
to rely on "Shetikah k'Hoda'ah" in order to substantiate the testimony of
the single witness!
(b) RITVA. The Ritva explains our Sugya as discussing the trustworthiness of
a single witness. According to the Ritva, two things need to be understood:
the "Tzerichusos" of the Gemara (which imply that the Sugya is discussing
"Shetikah k'Hoda'ah" and not the trustworthiness of a single witness), and
the Gemara in Gitin mentioned above (which implies that without the logic of
"b'Yado," the testimony of a single witness is not acceptable).
The Rishonim (see Ran) explain that the Gemara in Gitin is unique and it
does not apply to the cases in our Gemara. Since the worker's job is to
ensure that the food is prepared properly and does not become spoiled or
ruined, there is a form of a Chazakah that he did his job and nothing went
wrong, and that he did not let the food become Tamei. Therefore, in order to
accept his testimony that the food did become Tamei, the logic of "b'Yado"
is necessary, for without "b'Yado," his testimony is contradicted by the
Chazakah.
Regarding the "Tzerichusos" of our Gemara, the Gemara is not saying that we
believe the Ed Echad's testimony only because of "Shetikah k'Hoda'ah."
Rather, the Gemara is giving reasons why we may assume that the defendant
did not *deny* the Ed Echad's claim. Even though an Ed Echad's testimony is
normally accepted in cases of Isurim, if the subject of his testimony denies
what the witness says, then the testimony of the witness is *not* accepted
(it is considered one witness against one witness, and they cancel each
other out). We might have thought that the reason the defendant is not
responding to the Ed Echad's claim is because he feels that the single
witness is speaking nonsense and is not worth answering. Therefore, we must
be taught that his silence is to be viewed as Hoda'ah (or at least that he
is not arguing with the Ed Echad's testimony).
(c) RAN. The Ran agrees with the view of most Rishonim that the testimony of
an Ed Echad is believed even without the logic of "b'Yado." However, the Ran
explains the "Tzerichusos" of the Gemara in the same manner as Rabeinu
Tam -- i.e. that they are reasons for saying "Shetikah k'Hoda'ah," and he
introduces a new understanding of why the testimony of an Ed Echad is
accepted.
The Ran first points out that the concept of "Shetikah k'Hoda'ah" of our
Gemara applies only to cases of Isurim. Such "Shetikah," silence, could not
be viewed as Hoda'ah with regard to other laws, such as cases dealing with
monetary matters. The degree of Hoda'ah necessary to take money away from
someone is not accomplished by merely not answering an Ed Echad's claim.
Moreover, the lack of response to an Ed Echad's claim cannot even be
considered a Hoda'ah to create a situation of "Shavya a'Nafshei" (wherein a
person, through his own explicit admission, makes something Asur to
himself), which is a type of Hoda'as Ba'al Din in reference to Isurim. The
Hoda'ah by itself has no Halachic ramifications.
On the other hand, the Ed Echad's testimony alone is not sufficient either.
The Ran proves this from the "Tzerichusos" of the Gemara, as mentioned
above.
The Ran, therefore, teaches that there is a new, unique type of Hoda'as
Ba'al Din. It is not a Hoda'ah that works through the mechanism of
admission, but rather a Hoda'ah that enables the testimony of an Ed Echad to
be believed. Since only one witness is present, we cannot accept his
testimony as we accept the testimony of two witnesses. Rather, the testimony
of the single witness needs something else to strengthen it in order to give
it validity. It is the silence of the defendant that gives strength and
credence to the Ed Echad's claim. These two factors together -- the
testimony of the Ed Echad and the silence of the defendant -- combine to
give the Ed Echad the trustworthiness that is needed in order for us to
accept his testimony.
The Ran goes on to explain the Machlokes between Rava and Abaye in
accordance with this explanation. Although Abaye requires that there be
Hoda'ah, it is not through the mechanism of Hoda'ah (Hoda'as Ba'al Din) that
the claim is substantiated. Rather, the claim is substantiated through the
new Ne'emanus of "Hoda'ah l'Ed Echad" ("admission to the testimony of a
single witness"). Rava argues with Abaye. If Abaye held that the Ed Echad
alone could be relied upon, then Rava perhaps might have agreed. But since
Abaye is discussing a case of Davar she'b'Ervah, Rava rejects Abaye's new
form of Ne'emanus and maintains that two Edim are necessary.
(According to the approach of Rabeinu Tam, the Machlokes between Rava and
Abaye still requires explanation.)