We show that a blank-tape-halt-checker can not exist by reduction from the Halting Problem. Assume that a blank-tape-halt-checker BT(P) does exist. We build a program named HC, which takes a program P and a string w as input, as follows: HC(P,w): (1) Build a Turing Machine that takes no inputs. It first writes the string w to its blank tape, and then runs P on that tape. Call this no-input turing machine TM. Note that TM effectively runs P on w. (2) Call our blank-tape-halt-checker on this TM: BT( TM ) (3) If BT(TM) reports that TM halts, halt and output "Yes" (4) If BT(TM) reports that TM does not halt, halt and output "No" As long as BT exists, this constructed HC is a legitimate program. All of the steps are computable -- writing a single, known string to a blank tape, running a turing machine's program, and conditional-checking. However, note that HC(P,w) is a halt checker! (A) If P halts on w, HC(P,w) returns "Yes" (because TM will halt on no input, so BT(TM) returns "Yes") (B) If P does not halt on w, HC(P,w) returns "No" (because TM will not halt on no input, so BT(TM) returns "No") Since a halt-checker can not exist, we have reached a contradiction. Thus, our original assumption that the blank-tape-halt-checker exists was false. A blank-tape-halt-checker also can not exist.