Most fears are nothing but movements of thoughts. A thought is a language that we give for words, pictures and feelings. Put in a different way, a thought is just a movement of word, picture and feeling... You interpret a thought in your mind in a language that you are afraid, and you experience fear.
The process of creating fear takes place in the brain and is entirely unconscious. There are two paths involved in the fear response: The low road is quick and messy, while the high road takes more time and delivers a more precise interpretation of events. Both processes are happening simultaneously.
What happens when you are in a state of deep sleep? In that state there are no thoughts, and you experience no fear at all. If there is no thought, there is no fear. When you are in deep sleep, a snake may glide close to you, but you are not afraid of that snake in such proximity because you are not thinking about the snake. On the other hand, when you are awake, the sight of even a coiled piece of rope can fill you with fear, because you think that the rope is a snake.
Fears that are physical in their origin arise from a threat perceived in our immediate physical surroundings. For example, you may be in the jungle, and you know there are tigers in the jungle. You will genuinely be afraid. Even then, you can turn that fear into an enjoyable experience, what advertisers of adventure sports call an "adrenaline-pumping" or "hair-raising" experience. Such fear also has great survival value. Ask professional hunters and experienced trekkers, and they will tell you that it is fear that keeps them alert and alertness that keeps them alive.
You can work on reducing or eliminating your fear. If you have a fear, first understand the nature of the object that arouses it. Let us say you are afraid of your future. What you really fear is the uncertainty that surrounds events yet to happen. By living totally in the present and by planning ahead you can reduce the uncertainty and fear. If you do not know how to plan, you can take the guidance of consultants and counsellors. You cannot plan for all uncertainties but being prepared to an extent reduces your fear of uncertainties. Learn the art of enjoying it, too.
At times, even when we are thinking positively, negative thoughts and images intrude. How to prevent this?
I will begin my answer with an analogy. You have a computer and you switch it on. Windows 98 comes on. You don't want Windows 98. You get angry. You switch off the computer, and switch it on again. Still you see only Windows 98 on the screen. Then you buy a new computer, and that also displays only Windows 98. All the computers of the time work on Windows 98. Switching the computer on and off repeatedly will not change the situation. For, the built-in programming environment is Windows 98. You have to change the programming.
Similarly, the psychological programming inside you, your subconscious mind, should change before any real change can happen. Your subconscious mind comprises engrams – mental traces that have been created over life experiences. These consist of both positive and negative associations and act like computer programmes. So long as the programming remains the same, the computer will function only in the manner dictated by that programme.
Similarly, we have to change the programming of our mind. Wise thinking leads to discrimination of the good and the bad. When you have changed your programming, you start perceiving and acting positively. So it is wise thinking that holds the key to a positive frame of mind.