Madsen Pirie takes a swipe at Common Error No. 9, which goes:

“It is wrong to allow bright children to go to special schools. This deprives the ordinary schools of their beneficial influence.”

Pirie concentrates on the immorality of such a policy:

The vicious notion is that children, whether bright or not, should be regarded as the instruments of the ends of others, instead of ends in themselves.

However, he leaves unscathed the implied claim that such a policy actually would help unbright children.  Presumably he doesn’t care.  I certainly don’t, except insofar as the idea makes a mildly interesting blog posting.  I oppose this policy no matter how much good it might bestow upon the unbright, on the grounds that such compulsion is just plain wrong, and that compulsion in all other areas of life (definitely including educational life) does miles more harm than good, so why should this policy, even if some children might benefit from it, be any different?

If you support such a policy, but if your true purpose is to achieve more equality of outcome by making the bright less bright, by dumbing down the bright rather than raising up the unbright, then you wouldn’t care if such a policy really did make the unbright any brighter either, any more than I do.  You’d still favour compelling the bright to mix with the unbright, just as I would still oppose it.

But, if you think that such a policy is justified, provided it actually achieves the desired effect of making the unbright brighter, you would want to know if it actually does have this effect.  So, does it?  I don’t know for sure but I very much doubt it.  But then, I would, wouldn’t I?