Because all the evidence come from voluntary testimonials, so this is not a scientific method, which is based on testing a product over a set number of volunteers all of them put under the same experimental conditions. Unfortunately, this type of experiment is not easy or cheap to carry out. I also believe that in any experiment there could be bias involved, so experimental results are not always reliable.
I do believe Paraliminals work and I bought them on faith that they would work. Lots of forum participants appear to show that they gain benefits from them. I have gain some benefits from them.
