Philosophy for Children is an educational program developed for children in the United States in the 1970s. The program aims to develop children's ability to think critically, reflectively, and reasonably, and thus liberate them from hierarchies or power structures existing in society. However, according to some critics, children's voices may be understood only when they are treated as future autonomous citizens. We must draw attention not to how reasonable children's thoughts are, but to how our way of speaking for them becomes reasonable. This article focuses on the difficulty of understanding children's voices by examining Cora Diamond's paper “The Difficulty of Reality and the Difficulty of Philosophy." In it Diamond presents a distinctive interpretation of J. M. Coetzee's novella “The Live of Animals," which considered to be concerned with arguments in animal ethics. However, according to Diamond, the novella, by illustrating the difficulty of speaking for suffering animals -the problem that the protagonist is confronted with- teaches us how not to understand the Other's voice. Thus the teaching demonstrates a potential technique for understanding children's reasoning.