 The proof of the uncomputability of CIRC? uses the construction of a hypothetical and circle-free machine \(T_{decide}\) which computes the diagonal sequence of the set of all computable numbers computed by the circle-free machines. Hence, it relies for its construction on the universal Turing machine and a hypothetical machine that is able to decide CIRC? for each number n given to it. It is shown that the machine \(T_{decide}\) becomes a circular machine when it is provided with its own description number, hence the assumption of a machine which is capable of solving CIRC? must be false.