Conscious mind creates doubts. It also creates fear of the unknown. It is the inherent characteristic of the conscious mind to create doubts and subsequent insecurity. Doubts are based on the level of consciousness. On a sunny morning, when basking in the warm rays, the conscious mind is sure that its morning and there is sunshine. But, a person who sleeps inside a blanket with curtains blocking rays from entering the room can never be sure of the situation outside his windows. His mind speculates. So, the available data and the level of consciousness creates the doubt.
Doubts block progress. Doubt about anything is a hindrance. Those who dare has always found some result. Sometimes it is just a mediocre experience. Sometimes its blinding truths. It is certainly good to be brave. The roots of doubts rest in inertia (Tamas). The more tamasic a person is, the more doubts he will have.
Reasonable risks always helps progress and self esteem. Foolish risks often ruin the man. Reasonable risks are stemmed out of the intellect. Foolish risks are offsprings of emotions. What ever gets born out of intellect has longivity while every action born out of emotion usually carries the seeds of catastrophes.
All doubts will vanish with higher awareness. When we have doubts about the weather outside, just open the curtains and look outside. Likewise, whenever doubts arise, do the action and do not resort to speculation. The best way to beat doubts and even inertia is by resorting to ACT.