The purpose of this study is to examine the ideological basis for overcoming the pessimism surrounding communication with others with whom we disagree, and to look at the connection to education. For this purpose, the following methods were used. 1) Organize the concepts of “pessimism in communication” and “tolerance of mutual differences”. (2) Based on Nakano’s criticism in Nakano-Watanabe’s “Reciprocal Letter” (1949), I will discuss how to overcome “pessimism in communication. (3) Based on the “tolerance to accept each other’s differences” that maintained the connection between Nakano and Watanabe, I look at the connection to education. As a result, it was found that in education, (1) the opportunity to express words as “inner speech (thinking, thinking)” when different opinions are presented, and (2) the experience of explaining and listening to the contents of differences in order to maintain different ideas are important.