I’ve been re-reading a lot of Mill’s stuff recently and must admit that I find it less perfect than I found it when I first read him. This was true of Utilitarianism, and it is also true of the Autobiography.
Ultimately Mill comes off as a nice man, and as a reader you want to sympathize with him. But with many of his propositions he claims things are “right” or “wrong” when those aren’t really proper categorizations. And he is VERY liberal, which isn’t necessarily a problem but means that his perceptions are slanted. As far as specifics go, while I agree with him that the educational process (now as then) is not conducted as efficiently as it could be, I also believe that he–much like myself–is an exception to the normal standards of intelligence, so his comments that because he was reading Herodotus and Homer at 8 the school system is inefficient are bizarre. At 12, or 13, yes; at 8, no. And I think that Mill himself was probably too young to fully UNDERSTAND these works. He is right that the Socratic method is the most effective one for teaching. From a political perspective, I think his association with Comte is troubling, and the same goes for his self-categorization as a Socialist-in-waiting–he says the world isn’t prepared for the right kind of socialism, but that’s ALWAYS what Socialists say, which is why they are always “planning” and never quite executing.
As far as the writing is concerned, some of the paragraphs are too long. Several of the classical authors suffer from this problem, but often this is due to translators; in this case we can’t blame a translator.