When young people are sent abroad to finish their education, it is assumed that they are among the brightest and the best young minds in the land. Why waste all that expense on dumbbells?

However, there is good reason to question the intelligence, or at the very least the intellectual curiosity, of the Iranian students who have been demonstrating their support for Ayatollah Khomeini in this country.

They have come here to study everything from engineering to medicine. However well or poorly they have been doing in those pursuits, they appear to have learned nothing about the philosophy that governs the political system of their host country, or about their relationship to it.

They do not understand that it is our policy to try to maintain friendly relations with every foreign government that makes a claim to legitimacy or stability -- even with Red China and the Soviet Union.

They do not understand that when the people of Iran chose to replace a shah with an ayatollah, we tried to establish friendly relations with the ayatollah and discourage the shah from taking refuge here.

They do not understand the humanitarian basis on which the former shah was admitted to the United States for medical treatment.

They understand their determination to assert sovereignty in Iran, but not our determination to decide who can enter our country.

They understand their desire to get their hands on the shah's money, but they do not understand our inability to deliver it to them.

Nor do they understand the endless inconsistencies in their position. When the ayatollah was a fugitive from a shah who wished he would drop dead, and might have been happy to help speed that day, they thought it was right and proper for France to provide sanctuary for a political outcast. But when President Carter permitted medical help to be given to a critically ill shah, for whose demise the ayatollah now prays with great impatience, Carter was declared to be the devil incarnate.

Those brightest and best young minds of Iran think they have a right to enter our country, with or without our permission, and stage disruptive demonstrations here. But if they were in their own country, they would not dare stage such demonstrations against the government in power, whether it was a shah's or an ayatollah's.

They expect our police to protect them, but they would expect the Iranian police to split their heads open.

They think they have a right to hold our embassy personnel hostage, but would denounce us as servants of Satan if we were to give their embassy personnel the same treatment.

It appears to me, therefore, that the Iranian students have been totally immune to the new milieu in which they have been studying dentistry, political science, and all those other disciplines that will help them take Iran back to the 7th century culture they so deeply admire.

They ought to look up from their books occasionally and observe the people who are their hosts. They ought to learn something about freedom and democracy. And if they can find in their school's curriculum a course on how to think, they ought to sign up for it forthwith.

That's the trouble with students. Quite often the last thing they study is life, and the last discipline they master is the common sense that will enable them to live life intelligently. POSTSCRIPT

I am reminded of a thought that has been expressed in various ways. My own wording of it is, "Middle age is that time in life when the best thing to exercise is discretion."

Young people who think they know it all can be exasperating, but those of us who are older must try to be patient with them. Some day they'll grow old enough to be just as stupid as we are now. HOW'S THAT AGAIN?

Now that we will have to get along without Iranian oil, you may be interested in some energy conservation recommendations circulated by the National Institute of Building Sciences and the U.S. Department of Energy. They say, in part:

"If residential energy conservation could be cut 25 percent, 1.5 to 1.8 million barrels of oil could be saved."

DOE, you've done it again, haven't you? How much would we save if we cut conservation by 50 percent? GOLD'S FOOD AND DRINK LAWS

Anything that tastes good causes cancer. Anything that smells good is fattening. Anything that looks good is bad for your heart. Among the liquids, anything that makes you feel better will make you feel worse tomorrow. lIf you don't eat or drink anything at all, you'll die, but at least you'll die healthy.