The article starts with a brief survey of Unprovability Theory as of summer 2006. Then, as an illustration of the subject’s model-theoretic methods, we re-prove threshold versions of unprovability results for the Paris-Harrington Principle and the Kanamori-McAloon Principle using indiscernibles. In addition, we obtain a short accessible proof of unprovability of the ParisHarrington Principle. T...
