 However, a complication for the identification of Heyting’s and Kolmogorov’s explanations of logic is introduced by Kolmogorov’s also accepting, in a particular case, solutions that do not consist in a carrying out a concrete construction. Kolmogorov said that “As soon as \(\neg a\) is solved, then the solution of \(a\) is impossible and the problem \(a \rightarrow b\) is without content” (Kolmogorov 1932: 62 [Mancosu 1998: 331]), and proposed that “The proof that a problem is without content [owing to an impossible assumption] will always be considered as its solution” (Kolmogorov 1932: 59: [Mancosu 1998: 329]). Taken together, this yields a justification of Ex Falso, \(\neg a \rightarrow(a \rightarrow b)\).