[waterhouse]

> This assumes that the existing system is already a perfectly ordered meritocracy.

No, just that it's as close as you can get with the imperfect tools at your disposal. Even if your tools are really bad—like, if the variation in scores on your test suite is 10% ability, 90% luck—well, if that's the best tool you have for sorting by ability, then you should use it, and to the extent that you ignore its recommendations in favor of racial or other preferences, that will lower the average ability of the candidates you accept. (Unless your tool is so bad that selecting by race outperforms it—which is a very unfortunate situation, and one that should be avoided as much as possible.)