On the schools of thought definition, I have used this one: a group of scholars who hark back to a single writer or small number of writers for inspiration and/or doctrinal support. Hence the modern Austrian school (in the US) harks back to Carl Menger. There are other Austrian schools (in Germany for example) that hark back to Boehm-Bawerk. The classical school (so named by Marx) but typically hark back to Adam Smith, etc. Marxists hark back to what's his name. I hope this helps. Laurence S. Moss