The spate of public appearances by Ronald Reagan last week bears witness of benign intent. The new president plainly wants an open administration. Rightly so, for he is -- as one of the more recent corruptions of the language has it -- a fine communicator.

But there is a difference between communication and content. Analyzing the content of one event -- the interview with five reporters early in the week -- raises misgivings about both the president's approach to foreign affairs and the foundations of his thinking on economic policy.

One important piece of news emerged from the interview with the five. Speaking of the relationship between the tax cut and reductions in government spending. Reagan said: "Well, we're trying to link this into a single package and get the package passed."

The tilt toward a single package represents a notable gain. During the campaign, Reagan was an easygoing supply-sider addicted to massive Kemp-Roth tax cuts who paid attention to spending reductions only as an afterthought and under the rubric of waste and fraud.

The shift in position reflects a message delivered in the past few weeks by Federal Reserve Board chairman Paul Volcker, the congressional leadership and the financial market. Together, they have convinced the president, as he indicated in his Thursday night speech, that a tax cut without connected reductions in spending would be dangerously inflationary.

A second item in the interview was given undue attention by journalists laboring under the delusion that arms control represents the cedntral fiber of Soviet-American relations. Reagan said of the Russians: "Anytime they want to sit down and discuss a legitimate reduction of nuclear weapons, we will get into such negotiations." In fact, as he said in the interview, he had been saying precisely that "all through the campaign."

Not only was there no news in the comment, but giving it big play bred false hopes. The unpleasant fact is that the United States is now stretched thin in its nuclear armament. No significant reductions in missiles, bombers, or submarines are possible without increasing vulnerability and thus giving an added incentive to an attacker. While this country has an undoubted interest in resuming arms control negotiations with Russia, it hurts the cause -- now as it did in the first days of the Carter administration -- to talk of deep cuts.

The Middle East also provided considerable copy. The president said that Israeli settlements on the West Bank of the Jordan River, while not "illegal," were "ill-advised" and "unnecesssarily provocative." He said of the Palestine Liberation Organization that it Practiced terrorism," and might not represent the Palestine Arabs. He also asserted the need for some kind of American "ground presence" around the Persian Gulf.

I happen to agree on each one of those points. But is it wise for a president to come so clean? Won't the Saudis and other Arabs be offended by his overt denial of their views on the settlements and the PLO? How likely are they, or any othe Arab country, to afford this country the right to station ground troops on their territory? Doesn't expression of the desire for bases, in any case, up the price? Why talk much about the Middle East anyway, when events have called at least a temporary time-out?

Lastly, the press interview featured a long, rambling venture into the president's concept of economics. Reagan said: "Back in the turn of the century, the classic economists used to explain -- I don't know why we ever forgot it -- they used to explain business slumps as everytime government began . . . increasing the percentage of the earnings and the gross national product of the people that it was taking."

The reason we forgot that teaching is that it never happened. There were no economists of any note writing about business slumps at the turn of the century. The pioneers in the subject -- Joseph Schumpeter, for example -- began studying business cycles about 50 years ago. Government was so tiny a part of the economy at that time that it barely entered their analysis. If anything, they tended to blame slumps on the pattern of business investment -- notably the exuberance of entrepreneurs who pushed their ware to the point where they ran out of suckers to sell to.

Besides imagining the past, Reagan invented the present. The notion that business downturns are mainly a function of excessive government is sheer ideological junk. If that view were correct, the United States -- where the federal share of GNP rose from 2.5 percent in 1929 to 23 percent in 1980-- would have experienced 50 years of depression. West Germany -- where about 50 percent of GNP passes through the hands of government authorities -- would be an economic basket case.

None of this has a necessary bearing on the program trhe president is about to put forward. But it is risky business all the same. These days a president who uses the bully pulpit to talk nonsense about economics is like an emperor who carries a sign that advertises nudity.