LEV99 Based on the Torah itself, there is only one unique aspect to the pig. The Torah's two signs for a kosher animal is that the animal must both chew its cud and have split hooves [this verse]. Most animals in the world have either both symbols and are kosher or none of the symbols and are not kosher. But the Torah says that there are only four exceptions that have one symbol, not the other [Leviticus 11:4-7] (until today, they have never found a fifth exception in the entire planet). Three of the exceptions, the camel, the rabbit, and the fox, chew their cud but have no split hooves. Only the pig (of all the animals on earth) has split hooves but does not chew its cud. Why is that so detestable to the Jew (more than other animal)? It has been suggested that this symbol of the pig is the only animal in the world that has the outward symbol of kosher and not the inward symbol. Thus, the pig symbolizes the animal (and person) that is kosher on the outside but not on the inside. Someone who appears righteous to the world but who, in reality, is not righteous is indeed detestable to the Jew. This type of hypocrisy, "saying one thing (positive) but thinking another (negative)" is one of the categories of people that God detests (Pesachim 113b). A student whose inside did not match his outside was not permitted into the beit medrash (study hall) (Berachot 28a). The Talmud (Sanhedrin 104b) analyzes why the Megillah of Eichah, which describes the Temple's destruction, is in alphabetical acrostic order except for the letter Peh and the letter Ayin, which are reversed. It says that unlike the alphabet, when the spies in the desert put their mouths (Peh) before what their eyes (Ayin) had seen, they reported that the land should not be entered. It was for that sin, saying what they did not really see, that the Jews were not allowed entry to the land until that generation was wiped out and a new generation would be able to enter the land of Israel. Therefore, the degree of reprehensible of any person who acts differently from the way he or she thinks is reflected symbolically in the pig who looks kosher on the outside but is not on the inside. It is possible that it is for this moral reason that the pig is universally viewed as reprehensible to the Jew.