A treatment whose successes prove it and whose failures also prove it — because the failures did not believe enough — has removed itself from the world of testable claims. This is not a debating point. It is the difference between a treatment and a doctrine, and it is the sentence this site tells people to refuse on sight.
The claim appears constantly in retraining communities: if there is any hesitation, doubt, fear or belief that it is nonsense, it will not work; the subconscious will detect the lie. It is offered as neuroscience. It functions as a guarantee against disproof.
It also does something to the people it is said to. Someone who did the program fully, believed, saw some progress, and was still made ill by a moldy house is told the failure was theirs. That is the medical dismissal of the last thirty years with the blame moved from the doctor to the patient.
Every treatment that has ever been shown to work was shown by counting its failures. Randomized trials exist so that failures count. A claim structured so that failures cannot count cannot be tested, and an untestable claim is not evidence of anything, however many people it has helped. That is not an opinion about brain retraining; it is what testability means.
The contrast is the actual evidence: one randomized trial in which people who did the practice fully showed changed perceptions and an unchanged illness. Those participants did not fail to believe. The treatment failed to change the sensor, and the trial was designed so that could be seen.
Hope that requires you to blame yourself when it does not arrive is not hope.
Among people who tried a program and were not helped: what they did, for how long, how fully — so "didn’t believe enough" can be tested against the record instead of asserted.
Any claim that cannot fail has stopped being a claim about your body. Refuse it, whoever says it, and keep the parts of nervous-system work that make no such demand.