 Lederman (2018a) proposes a radical solution to the paradoxes. In the case of the coordinated attack, he argues that rational generals who commonly know that they are rational will attack if (and only if) they have common knowledge that they will attack; since common knowledge is not attainable by exchanging messages, they will not attack. However, admitting that the generals do not commonly believe that they are rational, a simple model can be built showing that such generals do attack without common knowledge that they will. Similarly, in the case of the e-mail game, he shows that if players can be of an irrational type (so that she chooses game \(B\) even if her expected payoff is lower than for choosing game \(A\),) and one player believes with sufficiently high probability that the other player is of the irrational type, then players can coordinate on game \(B\) after a finite number of messages have been exchanged. Thus, Lederman (2018a) argues that we should take common knowledge of rationality to be a simplifying assumption, useful to produce tractable mathematical models and yet generally false “in the wild,” where a commonsense notion of rationality does let generals and laymen easily coordinate after a small number of message exchanges. Thomason (2021) takes issue with Lederman’s use of the notion of commonsense rationality, and argues about the importance of considering instead the cognitive and deliberative processes that lead to the emergence of both individual and commonly held attitudes. Despite their disagreement, both Lederman (2018a, 2018b) and Thomason (2021) emphasize the importance of the relation between (commonly) held beliefs or knowledge and practical reasoning. An interesting application of practical issues pertaining to the attainability of common knowledge is offered in Halpern and Pass (2017), where a blockchain protocol (and consensus and hence coordination therein) is analyzed in terms of suitable weakenings of the notion of common  knowledge.[35]