Take the matter of expansion. Providing more education for more people has been the aspiration of most Scottish educationists this century, and the fruits of this are now evident. The proportion entering higher education, for example, quadrupled between 1962 and 1993 (from 9 to 38 percent). An even more spectacular example is in the secondary school curriculum. In 1962, the traditional Scottish broad education - admired by Mr McMillan - was flourishing only for the one in eight pupils who completed the full five-year senior-secondary course. In the 1990's almost all pupils ages 14-16 are studying English, mathematics, a science, a social subject, and a language. The aspirations to a common curriculum - which Mr McMillan fears is mere "political correctness" - has given wide access to some kind of breadth of curriculum for the first time ever.
And, in the examinations which pupils do at the end of this broader curriculum, success has expanded in an almost revolutionary way. In 1962, three-quarters of young people left school with no nationally-recognised qualifications. In 1994, this had dropped to one quarter. In 1965, just 4 per cent of leavers had five or more Highers; by 1994, this had risen to 18 per cent.
Within the overall expansion has been an extension of educational experience to social groups that were denied it before. In that 30 years, girls have come to have equal access to higher education, to examination passes, and to a full curriculum. Mr. McMillan fears that comprehensive education has hindered the opportunities of working-class young people, but the overall statistics simply do not support him. Working-class entry to higher education has expanded at the same rate as the overall entry, so that a working-class youngster in 1993 was four times as likely to get to university as a person of similar socio-economic background would have been 30 years before.
It is common to reply to such statistics by dismissing them; what matters, surely, is the quality of the educational experience. But the point about the broad statistics is that, at the minimum, they show a much wider participation in something which society has agreed to call "education". More young people get access to the citizenship that can flow from being in school, or possessing a certificate, or progressing to university. That is not to deny that there remain barriers to access - poverty, racism, sexism of attitudes despite girls' greater access. The point is, simply, that things have got better, in some respects substantially better.
So why the concerns? No doubt some critics of Mr McMillan's argument will dismiss it as reactionary nostalgia. But that is to miss a crucial change in recent years which he too ignores. The concern with mere numerical expansion has shifted towards a concern with quality. That shift could only happen once the expansion had gone as far as it now has: you have to have people in the educational institutions before you can try out different programmes for them.
Of course, there are many different definitions of quality, and the enthusiasts for the Scottish Office's quality assurance might not have a lot in common with, say, the proponents of thinking skills or of tackling racism and sexism. But, in a sense, all are responses to the problem of how to improve an education system that is universal and yet also increasingly expected to treat students as individuals.
A good example is Mr McMillan's worries about mixed-ability teaching. This came about because the 1960s generation of educational reformers actually shared his commitment to students as individuals. They argued that individualism was being stultified when pupils were assigned invidious streams, and no one of Mr McMillan's camp has ever adequately answered that point. But the more realistic of the 1990s reformers have gone beyond that to asking the kinds of questions posed by Mr McMillan. How do you allow students' individuality to flourish when they are in large classes with the constraints of external examinations? Mixed ability is then a necessary condition of a system that develops individuals - streaming allowed individuality only for an elite - but we have now learnt that it is by no means sufficient.
Educational nostalgia can be useful if it provokes a rethinking of educational progress. But it should not be allowed to get in the way of recognising that progress has taken place, and that further change is needed precisely because of the success of previous reforms.
Lindsay Paterson is professor of educational policy at Moray House Institute of Education.