Gary Thomas can't think of any "major social-scientific achievements" ("In search of singular insight", 9 July). Well, Nobel prizewinner Amartya Sen, in his book Poverty and Famines: An Essay on Entitlement and Deprivation (1981), showed that many famine deaths stem from a lack of "entitlements" to food, not the lack of food itself.
Sen's insight is important when the Rockefeller and Gates foundations plan another "green revolution" in Africa. Some experts urge the large-scale use of genetic modification to solve food crises. But first we should ask who such technical fixes benefit, and consider whether political-economic reform could not assure entitlements to food more effectively than big science. Sen was probably not the first to observe entitlements, but he was able to affect public policy because of his university connections.
Bruce A. Scholten, PhD Honorary research fellow Geography department, Durham University.