• Korean Journal of Logic
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• v.22 no.3
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• pp.417-446
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• 2019

The operation theory of the Wittgenstein's Tractatus Logico-Philosophicus is the essential basis of the philosophy of mathematics of the Tractatus. Wittgenstein presents the definition of cardinal numbers on the basis of operation theory, and suggests the proof of "$2{\times}2=4$" by using the theory of operations in 6.241. Therefore, in order to explicate correctly the philosophy of mathematics, it is required to understand rigorously the theory of operations in the Tractatus. Accordingly in this paper, I will endeavor to explicate operation theory of the Tractatus as a preliminary study for explicating the philosophy of mathematics of the Tractatus. In this process, we can ascertain Frascolla's important contributions and fallacies in his reconstruction of 6.241. In particular, we can understand the background that in 6.241 Wittgenstein made mistakes and that there he dealt with the addition operation of the theory of operations, and on the basis of this, we can reconstruct correctly 6.241.