Alternate pedagogies (Montessori, Waldorf, etc.) seem to work quite well for early childhood education, but I'm very skeptical of them for middle school, and especially high school (what Montessori defines as "3rd stage"). The reason for this is that extremely few people I've met who went to such high schools came out of them with levels in science/math that could be reasonably qualified as decent (and often borderline on catastrophic).
One of the main issues is certainly that some of those pedagogies do have pseudo-science/religion baked in, and they have a hard time ridding themselves from that past (notably Waldorf). Another problem is that the kind of teachers who are attracted to these pedagogies rarely have scientific/mathematical backgrounds, and as a result this aspect of the education suffers. It's a problem that they don't like to talk about.
The hard thing to wrestle with here is that for many scientific disciplines, hardcore reading and memorizing is vastly more efficient than inferring everything from observation and first order principles. Now you don't want to overcorrect and do ~only~ that, but there's a reason medicine students spend many years cramming.
I can confirm. Montessori education is great for kids under 12. For middle or high school, it was actually Maria Montessori who said, when asked what she saw as the best education for teenagers, that it was useless to try to force adolescent to concentrate on intellectual work. Instead she recommended an Earth school, where children would live close to nature, eat fresh farm products, and carry on practical work related to the economics of supplying food, shelter, transportation, and so forth.
The Montessori middle- and high schools that currently exist, at least in Europe, do not follow Montessori's advice at all. Instead they have a kind of half hearted mix of regular education with some elements of lower age Montessori, such as more responsibility to make your own homework planning. For many teenagers this is not a good combination and they drop out.
I think you're right, the issue is not that alternative schools can't teach science, it's that often they don't.
I have friends who had an alternative education that got almost no maths and science education, but I know of other schools where this is not the case.
previous parents from the school started an alternative high school (years 7 to 12) http://www.alia.vic.edu.au/about.php that has a strong maths science programme.
Both schools are very successful, and I think the key aspect is that they have managed to create a culture where the kids accept that they will have to do things that are tough, like run laps around the oval in the rain or grind their way through maths problems to achieve what they want, but this happens in an emotionally supportive environment.
The kids seem to work harder physically and mentally than kids at any primary (elementary) school I've seen in this country, but they also really look after each other.
extremely few people I've met who went to such high schools came out of them with levels in science/math that could be reasonably qualified as decent
Hi, nice to know you. Montessori-educated until University here. Even in high school, it's all about the learning material: as long as the teachers were skilled enough to make me interested in the subject, there was hardly any limit to what I could take in. I left school with high marks across the board, with five languages and all STEM subjects except biology (because I hated the learning material with a passion).
That said, my parents encouraged the same at home so it's not just my school: I wrote my first BASIC program with my father when I was nine, and there was a surplus of construction toys (Lego, Mecano, electric science kits) at home as well.
(edit: I'm not familiar with official "Montessori" policy on high schools, but I want to add that our school roster was partly free: we had a number of mandatory class hours for each subject, but were expected to spend more time in school than just our roster: all teachers had "open hours", which you could use to get additional mentoring from the teacher, peers or sometimes senior year students)
One of the main issues is certainly that some of those pedagogies do have pseudo-science/religion baked in, and they have a hard time ridding themselves from that past (notably Waldorf). Another problem is that the kind of teachers who are attracted to these pedagogies rarely have scientific/mathematical backgrounds, and as a result this aspect of the education suffers. It's a problem that they don't like to talk about.
The hard thing to wrestle with here is that for many scientific disciplines, hardcore reading and memorizing is vastly more efficient than inferring everything from observation and first order principles. Now you don't want to overcorrect and do ~only~ that, but there's a reason medicine students spend many years cramming.
See: "Does Waldorf Offer a Viable Form of Science Education?" http://www.csus.edu/indiv/j/jelinekd/publications/waldorfsci...