Accuse President Reagan of having done a good deal of harm to public education and you get no argument from me. His administration's reductions in student loans, vocational education and the Title I program, in addition to his recommendations for tuition tax credits, add up (in my view) to an assault on education.

But in the raging debate between the administration and the nation's largest teachers' organization, the National Education Association, on the question of merit pay, the administration has the better of the argument.

A recent episode of PBS's "MacNeil- Lehrer Report" makes the point. Secretary of Education Terrel Bell urged the public schools to "take a page from the higher-education book" and find ways to reward outstanding teachers without promoting them out of the classroom. He had in mind something like the current Tennessee proposal to institute senior- teacher and master-teacher ranks, so that superior teachers not only will earn more money but also be available to help younger teachers improve their competency.

NEA President Willard McGuire was having none of it. "When you name a few teachers as meritorious," he said, "you are saying that the others are not meritorious." And that, of course, would be dreadful.

"If we are going to name 15 percent of the teachers as being meritorious, for example, then parents of the majority of students will see that their children are destined to be taught by non-meritorious teachers, and I believe that the tension that will bring between parents and school administratiors, as they seek to have their child(ren) placed in a class with a meritorious teacher will bring us trouble that we don't want or need at this time."

The plain fact is that parents already know who the outstanding teachers are. And those parents with the concern and the clout to do anything about it already are exerting pressure to have their children taught by these exemplary teachers. It's hard to see how paying outstanding teachers for their unusual competence would increase that parental pressure.

McGuire, naturally, had other arguments. Merit pay would usher in favoritism on the part of evaluators (which, under most proposals, would include other teachers). It would produce bitterness on the part of teachers not seleced as outstanding. It would "be negative to the teamwork concept."

If the interviewers, Robert MacNeil and Charlayne Hunter Gault, were incredulous, it may have been because they found it hard to imagine a profession more demanding of teamwork than television, and harder still to imagine a system whereby television journalists would be paid solely on the basis of their college credits and their time on the job.

Secretaries, office managers, athletes and newspaper reporters routinely expect that outstanding performance on their part will lead to promotions and/or pay increases. Of course particular employees will complain that they have been underevaluated, or that they are victims of favoritism or of job assignments that didn't give them the opportunity to shine. But it wouldn't occur to them to argue against merit pay. Unless they are teachers.

And not all teachers. Albert Shanker, head of the American Federation of Teachers recently told his convention that there is a different public climate regarding public education and that teachers would be well advised to make the necessary adjustment. "They are saying: 'We're willing to help--to pour new billions into education--if you're willing to make some of the changes we want,'" said Shanker, making clear that he included the possibility of some form of merit pay.

Shanker may be doing what he can to make some distinctions between his union and the NEA, whose 1.6 million members make it a million members larger than the AFT. But he is also facing up to the reality that relatively low pay and relatively small opportunity for career progression are making teaching less attractive to the brightest young people, and that you can't make silk purses without silk.