 On Heyting’s explanation, however, a justification of Ex Falso parallel to Kolmogorov’s would seem to be impossible: while a problem may find a “higher-order” solution when it is shown that a solution is impossible, it makes no sense to say that an intention finds “higher-order” fulfillment when it is shown that it cannot be fulfilled. The notion of a solution seems to permit a reasonable extension that the notion of fulfillment does not. In his book from 1934, Heyting explains Ex Falso in Kolmogorov’s terms, not his own. After stating the axiom \(\neg a \supset (a \supset b)\), he says: