If Egyptian President Anwar Sadat is seriously planning to visit Israel, as he appears to be, it shows once again that he is a man who will run great risks and take bold gambles to get what he wants.

Even if he does not actually go to a country with which the Arabs are technically at war, his profession of a willingness to do so is itself a daring move that could expose him to furious criticism and perhaps rataliation from other Arab leaders.

Almost as astonishing as Sadat's offer to go to Israel is the relatively calm reaction to it in the Arab world. Less than a decade ago, according to experienced Middle East observers, any suggestion that an Arab head of state was actually contemplating acceptance of an invitation to address the Israeli Parliament would have brought howling mobs into the streets to protest.

There were no reports of any such reactions today. On the contrary, dramatic evidence of how things have changed in the Arab world was provided by the scene at the Tunis Hilton Hotel, where Arab foreign ministers went quietly about the business of departing, issuing the usual bland statements of gratitude to the host country, as if nothing unusual was happening.

Two members of the delegation of the Palestine Liberation Organization, who are known to be unhappy about Sadat's policy of approaching Israel directly, and were dismayed by the plan to visit the Jewish state, nevertheless managed to Joke about it.

"See you next week in Tel Aviv," one of them said. "You should know that nothing is impossible in the Middle East, even this," the other said.

"There comes a time when, if you're going to do something, you just have to do it," Tunisian official said. "You can only go on for so long listening to everyone else's ideas and making your mind up and then someone has to go ahead and do something. That's what Sadat has realized."

The only derect criticism came from Libya, one of the most militant Arab states but one that has been on the sidelines of recent Middle East developments. The official Libyan news agency said the People's General Congress held a special session to review the "regrettable and dramatic collpse of the stand of Arab confrontation with the Zionist enemy." The congress sent special envoys to Egypt and Syria to carry the Libyan message, the agency said.

Undoubtedly many Arabs are shocked and agered at Sadat's maneuver. Nevertheless, during the foreign minister's conference it appeared that Sadat, who first mentioned the idea of going to Israel in a speech last week, had enough support for his efforts toward a peaceful Middle East solution that he can make previously unthinkable moves without having to protect his rear.

Just before the speech in which he first proposed going to Israel to negotiate with Prime Minister Menahem begin, Sadat had conferred with the kings of Saudi Arabia and Jordan. Experienced observers at the foreign ministers' conference said it could be assumed that Sadat had Saudi support for his policy of doing everything possible to get the Israeli to Geneva Peace conference.

After that speech it was widely assumed that his offer to go into the Israeli Parliament itself was rhetorical hyperbole. During the foreign ministers' conference however, Egyptian sources said they thought he might be serious about it. After Sadat's interview with CBS television yesterday, in which he said he would accept a formal invitation carried by the American ambassador, it appears they were correct.

How this will be reiceived in Saudi Arabia is not known but it is highly unlikely that Sadat would take such astep if he thought it would jeopardize his political and economic support from the Saudis.

Syria is another matter. Sadat is due in Damascus on Wednesday for talks with President Hafez Assad, a man who is unlikely to be amused at the thought of his ally from the 1973 war giving Israel just the kind of recognition it has always sought without any indication that the Israelis are committed to giving up anything in return.

Egyptian officials admit that there are differences between Egypt and Syria over how to negotiate with Israel. The last time Sadat dealt separately with the Israelis, signing the second Sinal desengagement agreement in 1975, it led to a bitter split between Egypt and Syria that helped to prolong the civil war in Lebanon.

Egypt is committed not to make a separate peace agreement with the Israelis, but these pledges have been greeted with skepticism in Syria. What Sadat appears to be trying to do in convince the Israelis that the Arabs sincerely want peace and no longer seek the destruction of Israel, hoping in this way to persuade the Israelis to make concessions that would produce an agrement acceptable to Syria, Jordan and the PLO as well as Egypt.

Observers here pointed out that this is the first time any Arab leader has made this kind of gestureto the people of Israel up to now even those Arabs willing to accept peace have addressed themselves to other countries and refrained from gestures or comments that would concede Israel's legitimacyas country.

The Sadat who could make such a gesture is the same man whose career as president of Egypt has been marked by dramatic and surprising moves that seemed to be beyond his powers. He ousted intimates of former President Gamal Abdel Nasser to seize control of the country when few took him seriously. He sent his armies across the Suez Canal in the 1973 war,after saying for months that he was going to do it. That move changed the political atmosphere of the entire Middle East. If he goes to Israel, it would be the diplomatic equivalent of the 1973 was - a surprising and risky move that could expose him to failure and ridicule but could also help get him what he wants: peace and return of the Sinai