On his interpretation of constructivism, there are no mathematical constructions that are in principle non-computable. The proof that a function satisfying the

On his interpretation of constructivism, there are no mathematical constructions that are in principle non-computable. The proof that a function satisfying the property of "busy-beaverness" couldn't be computed thus is proof that the property does not determine a total function, so the classical definition is rejected as a non-constructive gesture at infinity.