In judging the people of Israel, there will be times when the judges will not know how to decide:
If a matter of judgment be concealed from you (KI YIPALEI MIMCHA DAVAR LA’MISHPAT), between blood and blood (BEIN DAM L’DAM), between law and law (BEIN DIN L’DIN), and between plague and plague (U’VEIN NEGA LA’NEGA), matters of dispute (DIVREI RIVOT) in your gates; then you shall arise and ascend to the place which Hashem, your G-d, will choose (Devarim 17:8).

Although this passage has many far-reaching implications, its primary focus is on the judges themselves, who might find a particular case too difficult. Writes Sforno (R. Ovadiah Sforno, 1470/1475-1550):
“Although you appointed judges for each city so that each court shall judge its city, nevertheless, if a doubt arises regarding the traditional teaching, the court of that city shall not decide according to its own deliberation, but the decision shall be made according to the deliberation of the majority of the High Court (in Jerusalem). [This is also the case] when [the local court] cannot reach a majority opinion.”

Thus, the lower courts will not dispute with one another. Here, the difficulty among the judges arises due to a doubt about the original law. The High Court takes final responsibility for transmitting the laws accurately.

Other commentaries suggest that the question arises within the lower court as a result of a genuine disagreement concerning the application of the law. Despite unanimity about the parameters of the law, the judges might nonetheless disagree how the law is to be applied in a particular case. Then the case is referred to a higher and higher court, possibly going as far as the Supreme Court that convenes in the chamber at the entrance to the Temple (See Rambam, “Laws of the Sanhedrin” 1:3; “Laws of Rebels” 1:4; 3:8).

Along these lines, Rashi, following Onkelos, writes that doubts may arise
“between blood and blood  between ritually unclean blood and clean blood.”
In other words, the judges cannot come to an agreement whether the blood they are examining renders the person tamei.
"between law and law between a decision of "not guilty" and a decision of "guilty."
This means that the judges cannot agree whether the facts prove the accused guilty.
“and between plague and plague  between a ritually unclean plague and a clean plague.”
This is because not every instance of a plague that resembles tzara'at makes the afflicted person tamei.

While Ibn Ezra and Ramban have different interpretations of these phrases, the essential idea is the same: The judges are unsure how to rule in any one of the many areas of Halachah civil law, criminal law, capital offenses, ritual law  so they take their case to the Sanhedrin.

The overall impression one gets is of an atmosphere of uncertainty that must be resolved, towards the goal of restoring order. To borrow a phrase of our Sages,
"so that disputes may not increase within Israel" (Megillah 3a, and elsewhere).

Disagreement and lack of clarity obviously is an undesirable state of affairs. Rashi echoes this in his comments on DIVREI RIVOT, “matters of dispute in your gates”, which may be read as a summary of the first part of the verse:
“When the wise men of the city disagree over the matter, this one declaring unclean and this one declaring clean; this one ruling guilty and this one ruling not guilty.” It was the function of the Sanhedrin to provide unanimity and structure, not only for the court system, but also for the entire Jewish People: When the Sanhedrin existed, there was no dispute in Israel. Instead, if a doubt arose in a Jew's mind over any law, he would inquire of the court in his city. If they knew, they would tell him. If not, the questioner and that court, or its agents, would ascend to Jerusalem and ask the court . . . who deliberate about the matter at that time and debate it back and forth until they reach a uniform decision, or until a vote is taken. They follow the majority and then tell all the questioners: "This is the halachah." Then they all depart (Rambam, “Laws of Rebels” 1:4).
Out of disunity emerges certitude.

The beginning of the dispute is, “If a matter of judgment be concealed from you” (KI YIPALEI MIMCHA DAVAR LA’MISHPAT). YIPALEI derives from the root PEI-LAMED-ALEF, Rashi says that this root always denotes separation:
“The matter is separated, concealed from you.”
To Rashi, YIPALEI means the matter is beyond you, it is abstruse. This type of murkiness leads to disharmony.

However, there is another side to YIPALEI. Chizkuni (R. Chezkiya ben Manoach, 13th century) points out that the root PEI-LAMED-ALEF has two opposite meanings. In addition to the meaning of "concealment," as in our verse, we also find
“when one will YAFLI a vow” (Vayikra 27:2).
In this verse, YAFLI means "express, enunciate" (see also Bamidbar 6:2). So, the same word can denote both indefiniteness and clarity!

We might add to this, that the word PELE means a miracle, a wonder (Shemot 15:11, and elsewhere). It is, therefore, both incomprehensible  a "wonder"  and a clear demonstration of Hashem's presence.

How can we reconcile these two aspects of YIPALEI?

It is important to recognize that, since no two human beings are alike, and since the Torah was entrusted to us to grapple with, a multiplicity of interpretations is inevitable. This is part of the "wonder" that is man: “The Holy One, Blessed be He, stamped all people with the die of Primordial Adam, and yet not one of them resembles the other” (Sanhedrin 4:5). Argument, in the pursuit of Torah truth, is not only legitimate; it is the ideal: “One who sees, in a dream, goring oxen [is thus given a sign that he] will have children who will "clash" over the Torah” (Berachot 56:).

For the good of the Torah society, standards of behavior must be set. Still, wherever Torah is studied passionately  from the classroom to the beit midrash to the Sanhedrin itself  it is a dynamic, living entity.