Thus not all mathematical theorems and hence not all the truths of mathematics can be derived from the axioms of logic alone. This means that the axioms of mathematics are not eliminable in favour of those of logic. Mathematical theorems depend on an irreducible set of mathematical assumptions. Indeed, a number of important mathematical axioms are independent, and either they or their negation can be adopted, without inconsister.cy (Cohen, 1966). Thus the second claim of logicism is refuted
To overcome this problem Russell retracted to a weaker version of logicism called ‘if-thenism’, which claims that pure mathematics consists of implication statements of the form ‘A-T’. According to this view, as before, mathematical truths are established as theorems by logical proofs.
Each of these theorems (T) becomes the consequent in an implication statement. The conjunction of mathematical axioms (A) used in the proof are incorporated into the implication statement as its antecedent (see Carnap, 1931). Thus all the mathematical assumptions (A) on which the theorem (T) depends are now incorporated into the new form of the theorem (A-T), obviating the need for mathematical axioms.