Following are excerpts from some of the issues discussed by President Carter at yesterday's press conference: Mideast

In the last few days we have seen, I believe, an historic breakthrough in the search for a permanent last peace in the Middle East, because of the true leadership qualities that have been exhibited by the courage of President Sadat, and the gracious reception of him in Israel by Prime Minister Begin.

This has been already a tremendous accomplishment. I think the importance of it is that there has been an initiation of direct person-to-person negotiations between Israel and the major power in the Mideast among the Arab nations who are Israel's neighbors. Lebanon, Syria, Jordan have a total population of about 12 million. Egypt has a population of 36 million, and has by far the greatest military force. And the fact that this strongest Arab country and the nation of Israel are now conducting direct negotiations is a major accomplishment in itself.

Two of Israel's most cherished desires have already been met. One is this face-to-face negotiation possibility and the other one is a recognitation by a major Arab leader that Israel has a right to exist.

In fact, President Sadat said. "We welcome you in our midst."

The United States has been very pleased to see this reduction in distrust and a reduction in fear and a reduction in suspicion between the Arabs and the Israelis. We have played a close consultative role with both of these leaders. We have on several instances recently acted as intermediaries, at their request. Both Prime Minister Begin and President Sadat have publicly expressed their reconfirmation that these exploratory talks are designed to lead toward a comprehensive settlement, including Israel and all her neighbors.

Sunday, President Sadat called for a conference in Cairo. This is likely to be held around the 13th of December, about the middle of December. We will participate in the conference at a high level. Assistant Secretary (Alfred L.) Atherton will represent our nation.

We look on this as a very constructive step. The road toward peace which has already led through Jerusalem will now go to Cairo; and ultimately we believe to a comprehensive consultation at Geneva . . .

I think it is constructive because for the first time the Arab position on those controversial issues has been spelled out very clearly for worldwide understanding, and I think the differences that have been faced by us and others for long years are now much more clearly understood by the public. The differences are still sharp. The resolution of those differences is going to be very difficult. I think to the best of his ability, President Sadat is speaking for the Arab world . . .

We and Egypt and Israel have all taken the position, publicly, and the same position privately among ourselves, that a separate peace agreement between Egypt and Israel to the exclusion of the other parties is not desirable. This is predicated upon the very viable hope that a comprehensive settlement can be reached among all the parties involved. If at some later date it becomes obvious that Jordan does not want peace, or that Syria does not want peace, or that Lebanon does not want peace in a settlement between Egypt and Israel to the exclusion to be pursued. But we certainly have not reached that point yet.

I think that the other Arab leaders do want peace with Israel. And I am certainly not even considering, and neither is Sadat nor Begin, any assumption that the possibilities for peace have narrowed down to just two nations . . . Soviet Role in Midest

In the past, I think it is accurate to say that the Soviets have not played a constructive role in many instances because they had espoused almost completely the more adamant Arab position. My own feeling is that in recent months the Soviets have moved toward a much more balanced position, as a prelude to the Geneva conference.

We have tried to spell out clearly, certainly since I have been in office and I think my predecessors as well, the United States' position. We disagree in some of those issues with the Soviet Union. We have not concealed those differences. We disagree in some instances because of the procedural items that are being discussed. But there is no division between us and the Soviet Union now that didn't exist before, and I would say that their positions have been much more compatible recently.

I wish that the Soviets had decided to go to Cairo. They have decided not to. But we will make as much progress as we can, following the leadership of Sadat and Begin, to make real progress in Cairo with the Soviets not present. And my belief is that the desire of the whole world is so great for peace in the Middle East that the Soviets will follow along and take advantage of any constructive step toward peace.

The fact that we do have differences of opinion is well known, and I don't think is an obstacle to an eventual peace in the Middle East. But we did not bring the Soviets in. They have been in since the very initiation of a Geneva conference . . . Energy Legislation

We still maintain that the prosition we put to the House and Senate in the energy proposal is the best. The House-passed version of the comprehensive energy plan is very close to what we have proposed, and we support the House position in almost every instance when there is a disagreement . . .

Obviously, both sides are very likely to compromise. They have already had compromises on literally dozens of issues. The three major issues remaining, as you know, are the electric rate reform - we have a good chance of having that resolved this week; the pricing structure in natural gas, and that conference committee will go back to work tomorrow - Senator Jackson is returning to Washington, D.C., then; and of course, the tax on crude oil, and these are to some degree interrelated. But I think we have got a good chance, still , of making progress now and I am going to maintain the position that we described last April as long as possible, support in every insentence the conferees that support our position . . .

[A]s I spelled out in my last fireside chat to the American people, there are three basic elements that I would require. One is fairness in dealing with consumers. The second one is meeting the goals of both conservation and production in the energy area. And third, an energy proposal that won't bankrupt this nation, nor seriously disturb the future budgets of our country.

That is a fairly broad base and I think it is an adequate parameter within which the conferees can work. But if any of those principles are violated, I would not sign the bill . . . Campaign Promises

I am trying to fulfill all of my promises. I think I was quite reticent in making those promises, certainly compared to some of my opponents. But we put forward already to the Congress proposals that carry out the major promises that I made, reorganization, energy, welfare reform and so forth.

We have also been successful, I think - when an analysis is made of what the Congress achieved this year. I think there is going to be a very pleasant reaction from the American people when they see the progress that we have accomplished. So I don't think I made too many promises. I think I am doing an adequate job in trying to fulfill those promises. There is a very heavy agenda for the Congress. It is much easier for the administration to evolve a proposal or to present legislation to the Congress than it is for Congress actually to pass it . . . Tax Revision

1977 is a year when we are seeing major legislation long overdue pased, hopefully, that cause some increases in taxes and additional taxes are necessary to restore the integrity of the Social Security system.

Some wellhead taxes are necessary to carry out a comprehensive energy policy and to hold down unncessary consumption. I would hope that all those changes in the law that bring about any tax increase would be concluded in 1977.

In 1978, there will be substantial tax reductions and combined with that will be an adequate proposal for a tax reform . . .

But there will be substantial tax reductions in 1978 combined with comprehensive tax reform . . .

Some of the more controversial items on tax reform that have been proposed to me - they would be very time-consuming and have very little monetary significances - might be delayed until later on because I feel that it necessary to expedite the effectiveness of substantial tax reduction and I am committed and the Democratic congressional leaders at least are committed to substantial tax reduction in 1978 as soon as we can put it through.