Article history: Received 30 November 2007 Available online 31 August 2011 JEL classification: D82 D83

Philosopher: Today, I suggest we discuss the important concepts of common knowledge and common belief. As far as I know, the first one to give a formal analysis of these concepts was the philosopher David Lewis, in his book Convention [131]. One of his examples is traffic conventions, about the role of common knowledge in how one behaves in road traffic. To explain this properly, I wonder if yo...

But game theory as we presently know it can not proceed without the fulcrum of common knowledge. Robert Wilson (1985) In the universal belief space [Mertens and Zamir (1985)] which incorporated all situations of incomplete information concerning a state space S , we de ne a `knowledge operator' in terms of beliefs. From this operator we derive (in the usual way) the concept of common knowledge ...

Lynn Margulis in the 1960s elegantly proposed a shared phylogenetic history between bacteria and mitochondria; this relationship has since become a cornerstone of modern cellular biology. Yet, an interesting facet of the interaction between the microbiome and mitochondria has been mostly ignored, that of the systems biology relationship that underpins host health and longevity. The mitochondria...