Thanks Shanta. Loving the discussion on this post. In your original post you said that the evidence that there are positive externalities is pretty thin. But in your response to my question as to why govts should subsidize education for the poorest, you say this is because of the social returns to education. Could you elaborate a bit more? Specifically how do you know the social returns to education are large enough to justify such a huge public subsidy? Perhaps there's a more normative reason for suggesting govts ensure all citizens can access a quality education i.e. fairness.