Комментарий к Бехорот 4:4

מומחה – he that received permission from the Nasi/President or from the Bet Din/Jewish court of the Land of Israel to permit firstlings. And even though that in a general way, he who studied the [Written] Torah [and the Oral Torah] and knows how to think and to compare by analogy [two laws] and to understand and form a conclusion by analogy, he one who is called a specialist/Mumheh, and when he is recognized and known and when he has acquired fame among the people of his generation, he is a specialist for the many, and he can judge as an individual, even though he did not receive permission from the Exilarch/head of the Diaspora community, [but] in regard to permission to permit firstlings, he is not called a specialist, and he is not able to permit firstlings other than after he receives permission from the Bet Din/Jewish court of those ordained in the Land of Israel, for the domain of the Exilarch does not have an effect in this.

If one who is not an expert sees a first born and it was slaughtered by his instructions, in such a case it shall be buried and he shall make reparation from his own pocket.
If a [non-expert] judge gave a judgment and declared innocent a person who was really liable or made liable a person who was really innocent, declared unclean a thing which was clean or declared clean a thing which was really unclean, his decision stands but he has to make reparation from his own pocket.
If the judge was an expert [sanctioned by the] court, he is exempt from making reparation.
It happened once that a cow's womb was removed and Rabbi Tarfon gave it [the cow] to the dogs to eat. The matter came before the sages at Yavneh and they permitted the animal. Todos the physician said: no cow or pig leaves Alexandria of Egypt before its womb is removed in order that it may not breed. Rabbi Tarfon said: “There goes your donkey, Tarfon.” Rabbi Akiva said to him: you are exempt, for you are an expert and whoever is an expert sanctioned by the court is exempt from reparation.
Our mishnah deals with the consequences of a judge who issues an errant ruling.
Section one: A person who is not an expert has no business declaring a first born blemished such that it can be slaughtered. If he does declare that it is blemished and the animal is slaughtered, the meat is prohibited and it must be buried. [Rabbi Judah would allow an expert to see if it was blemished, see yesterday’s mishnah]. In addition, the non-expert who allowed the animal to be slaughtered must repay the owner from his own pocket. Clearly, this is meant to discourage a non-expert from declaring an animal blemished.
Section two: The same is true in other cases of judicial decisions. If a non-expert judge renders a decision and later it is found that he made the wrong decision, he must make restitution from his own pocket. Non-experts should simply not make decisions, and if they do, they run the risk of incurring liability.
Section three: The mishnah now brings an interesting story of a mistaken judgment. A cow is brought in front of the sages so that they can determine whether the cow is a terefah, an animal with a wound/disease that would cause it to die within a short period. Such an animal may not be eaten. The sages in Yavneh determined that the animal was indeed a terefah. After making this determination, Todos, a doctor, testified that in Alexandria they would regularly remove the wombs from cows and pigs before they would allow the animal to leave the city. They would do this because they thought their cows and pigs were of superior breed and they didn’t want others to breed them. In any case, this proves that a cow with its womb removed is not a terefah.
Rabbi Tarfon realizes that he has made a mistake and therefore, exclaims to himself, “Tarfon, there goes your donkey!” Rabbi Tarfon is now going to have to sell his donkey to pay back for the loss of the cow.
Rabbi Akiva assures Rabbi Tarfon that he has not lost his donkey, because he is an expert, and an expert doesn’t have to make restitution when he renders a mistaken judgment.
I don’t know whether the mishnah is intentionally being ironic, but I find it funny that Rabbi Tarfon is an expert, even though he doesn’t know that the halakhah is that he doesn’t have to pay back the loss. In other words, he is an expert despite the fact that he has made two mistakes in one mishnah.

וישלם מביתו – and when he pays a Kohen, he gives one-fourth of its cost if it is a small animal, and half of its cost if it is a large animal. And because of this, he pays one-half [of its cost], for the money that is placed in doubt we divide it, but one can say that he loses it, for if he had not permitted this to himself, he would bring a complete expert and permit it for himself and he would consume it, but now it requires burial, and one can say, that he doesn’t lose anything, for perhaps, there wasn’t a blemish and a complete specialist would not permit himself [this], and perhaps a fixed blemish would not fall upon it ever until it dies. And the case where he doesn’t pay one-half for a small animal like that of a large animal, is because there is greater trouble to raise a small animal and he who permitted the firstling for the Kohen saved him from the great trouble to care for a small animal, for perhaps if he had shown it to another, he would not have permitted it and he would have great amount of care taking for it until a blemish would befall it, and for this reason, he would injure it that he would not have to pay other than one-quarter. But Maimonides explained this regarding another matter, and this is essential.

מה שעשה עשוי וישלם מביתו – for the one that where there is a case of indirect damage, he is liable to pay from his house/property for the loss that he caused to his fellow, but the one that does not judge a case of indirect damage explains our Mishnah explicitly that he engaged in business by hand [directly].

וזיכה את החייב – and the case can be found as for example, that he had a deposit with the lender and this [specialist] exempted the borrower [from paying] and he took the deposit in his from the hand of the lender and returned it to the borrower.

וטימא את הטהור – it is found that he did business with it by hand, as for example, that he brought before him pure animals to borrow them and he said that they are ritually impure and he took one reptile and had it come in contact with them, in order that there would be no further doubt and that his words would be validated.

וטיהר את הטמא – as for example that he took ritually pure fruit/produce and combined them with those fruit/produce that he purified, and he acted not in accordance with the law and defiled them.

ואם היה מומחה לבית דין – that he received permission from the Bet Din.

פטור – for he would not be able to tell him why he made this judgment for he was not expert in the laws.

האם שלה – her womb.

והאכילה רבי טרפון לכלבים – for they asked him about it and he said that it was “torn” (i.e., unkosher) and he fed it to the dogs.

שלא תלד – because their cows and pigs were very prominent and they sell them for a high price , and they want that they will not give birth for another kingdom in order that they will be needed, and they cut/sever their mother and she does not die, therefore, she is not “torn”/unkosher.

הלכך חמורך טרפון – you have lost your donkey, for you need to sell it in order to pay the cost of the cow to its owners.

שמומחה אתה – one and another thing he said to him, one – that he error in this matter of a Mishnah, for our Mishnah in [the third chapter of Tractate Hullin] “These are the torn animals’ [Mishnah 2], you took its mother which was kosher and we hold that he errs in the matter of the Mishnah, and the former argument is to be reinstated and we judge him appropriately and he does not pay. And furthermore, alternatively, and the weighing of opinions [of opposing views] – that is, as for example, two Tannaim or two Amoraim who argue, and the Halakha is not stated either according to this Master or according to that Master and the general practice is like one of them, and he went and acted like the other one, what is done is done and he pays from his estate.