Anything that involves invoking the powers of the whole mind requires conviction. Conviction, as I use the term, means to hold something to be true without evidence.
The reason is complex, but it boils down to the way the preconscious mind chooses what to present to the conscious mind. If you believe something, their is a natural tendancy to ignore data that contradicts the belief, and to find data that fills it. This is not prejudice, or closed mindedness. Rather, it is a way for us to make sense of our world. When the inner mind believes something is impossible, it presents options to the conscious mind to lead towards that proof.
What Paul Sheele seems to advocate on the tapes is something more than just belief. It's expectancy. Don't believe that PhotoReading works, or might work for you. expect it to work. But, remain flexable enough that if it doesn't work, you can figure out how to fix it (including the fix of using the gaurentee).