Can I? Will I be able too? What if I fail? You have the training, skills, and knowledge necessary to accomplish a task or conquer a challenge, but a doubt or a fear of failure keeps you from moving toward your desired outcome. Sound familiar? The Self-Help world is filled with advice and technologies to render every doubt into a certainty. I know of at least a dozen NLP (neuro-linguistic programming) and hypnotic techniques that are sure-fire recipes for eliminating doubt. Understandably, a life filled with certainty has an appeal, but let us not toss the doubt baby out with its old bathwater. The skill of proper doubting is an extremely useful resource.
Of course entertaining a doubt might not be the perfect activity while firewalking or approaching a potential dance partner; a doubt is a very useful thought to have when considering ones perceived barriers and weaknesses. Like a procrastinator that never gets around to putting something off, a person that gets into the habit of doubting his doubts might just find doubts silver lining.
Think of something you know, or truly believe to be true. A classic example would be the sun is going to come up...