Monday. We were high over Lake Erie, the day after President Carter's speech to the nation, and the presidential aide came to the rear of Air Force One, put his hand up on the ledge to steady himself, and started to talk. He spoke not of politics and politicians, but of ideas and intellectuals - of Christopher Lasch and naricissism and Daniel Bell and the contradictions of captalism - and the presidential aide said, damn, the country is in trouble.

It had been a good day for Carter - good speeches and good receptions and a good performance. Always, the president touched the same themes - the oil crisis, of course - but something else as well: The loss of confidence in the future. Carter had mentioned it in his speech and he had raised the subject during his days of relative isolation at Camp David, but it was not something new with him. It turned out the president had been thinking about this at least since the Spring.

It was May 30 that Carter had given a dinner party. The guest list was small and select. The president was there and his wife Rosalynn and his press secretary, Jody Powell. Also present were Pat Caddell, the president's pollster, Christopher Lasch, historian and author; Daniel Bell, a sociologist and coeditor of the magazine, The Public Interest; John Gardner, the former head of Common Cause and also an author; The Rev. Jesse Jackson, a minister and civil rights leader and journalists Bill Moyers of PBS, Charlie Peters of the Washington Monthly and Haynes Johnson, a columnist on leave from The Washington Post to do a book on Carter, his administration and Washington.

Some of those who attended that White House dinner have emerged as particularly influential with the president. One of them is John Gardner, whose book on morale reportedly made an impression on Carter. Another was Lasch, the author of The Culture of Narcissism, a book, one person said, "you see around the White House."

Since May, there have reportedly been other meetings - some call them seminars - with other intellectuals, although just how many meetings there were and with whom and with whom could not be determined. All of them have been held on an off-the-record basis, but some of those present said that at least by ltate spring, probably earlier, President Carter had become concerned about themes that seemed to have bloomed suddenly at Camp David. In fact, he had been thinkg about them for months.

Some of those mentioned as influencing Carter were not at the May 30 dinner party. One of them is James MacGregor Burns, a biographer of Edward M. Kennedy, but also the author of a book on political leadership. His book has been much in evidence around the White House, also. Another academic said to be influential is Robert N. Bellah, a University of California sociologist whose article, Human Conditions for a Good Society, caught the eye of White House staffers when it was printed in The St. Louis Post Dispatch. Bellah has been to Camp David. Also mentioned as an academic with a following at the White House is James Q. Wilson of Harvard.

The man who some say may have emerged as the most influential of the president's new "brain trusters" has been there all along. He's Pat Caddell, officially not a member of the White House staff but the person responsible for bringing the writings of the various intellectuals and academicians to the attention of the president. It was Caddell, the president's 29-year-old pollster, who first became concerned over survey data showing a loss of faith by Americans in both their own future and that of their country. He then turned to academicians $&(WORD ILLEGIBLE who had noticed this some time ago and had, in fact, already written about it.

It's hard to say exactly what this disparate group of academicians have in common.They are, for the most part, left of center, although some of them might be considered political or social conservatives - Daniel Bell, for instance. What they share is a view that America is in trouble, that its people are troubled and pessimistic about the future and that this is not a new development. It has been going on now for some time and has little to do with whomever the president happens to be at the moment. Gardner, for one, dates this lack of faith in American institutions from the era that began with the assasination of President Kennedy and eneded with the resignation of Richard Nixon. Lasch would probably agree, although he would emphasize the importance on inflation and the psychological effect on Americans of seeing their resources diminish - oil, for instance.

It's harder still to tell just precisely what Jimmy Carter makes of these theories - where he sees himself in all of this.

Those who have talked with him give him credit for making the effort - for defining the problem even if he, like they, have no ready solutions. And what you get as a journalist, sitting on Air Force One listening to a presidential aide talk about all this, is the notion that this president understands that for some things there are no buttons to be pushed - that there is a limit to what can be done by fiat.

But there is also something troubling about the message that we are all in this together - that there are some things bigger than any presidency and that we are all, citizen and president alike, traveling in the same boat down the same stream. It's not that way at all. He's the captain of this boat and he says he knows that now. Good. We're waiting for our orders.