If you have been around this forum for any length of time than you are probably well acquainted with the meaning and application of F.U.D. For the vast majority of us, ph-ud (my phonetic spelling!) needs no defining, but for those who are unfamiliar the acronym stands for Fear, Uncertainty, and Doubt. That hideous three-headed hydra. Many of us live underneath its dark cloud almost constantly, none of us are entirely immune from its debilitating effects. From a psychological perspective, however, the latter of the three poses the greatest threat (This is my opinion, of course. Someone may think that of fear, another of uncertainty). One may still act in the face of fear or act even though uncertain about a result. Doubt, however, is a “whole new kettle of fish.†Uncertainty is a nuisance, fear a menace, but doubt is the great destroyer. Doubt is the mortal enemy of achievement and almost always makes failure certain. While fear and uncertainty must be dealt with, doubt must be defeated. Plagued with self-doubt, one is incapable of clear thinking and a clouded or obscure judgment will most assuredly lead to an undesirable outcome, even where the outcome is inherently uncertain. Let’s use an analogy. Analogies are always helpful.
In sports, uncertainty is intrinsic to the competitive process. Unless an outcome has been determined beforehand (e.g., throwing a game) no one can be absolutely certain that one person or team will win over and against another. “Any given Sunday,†as the phrase goes. One may speculate, run a statistical regression analysis and factor probabilities (as of late it is de rigueur to include fancy stats in sports casting), or even rest assure on the grounds that one’s team never loses on a full moon—that is believe in sports mysticism. But just like playing the market, one can’t be entirely certain. In a similar vein, fear is often “redirected†or “channeled†in an attempt to allow an athlete or team to “harness†its power—in effect, to use fear as a motivational tool.
But, how can one “harness†the power of doubt? How does one believe in success while at the same time doubting their ability to achieve it? The old proverb states that the “double-minded man†is unstable in all his ways…not the fearful man, or the uncertain man. It is the “double-minded,†the doubting man that stands on unstable ground. Instability of any kind must assuredly give way under pressure. The body responds to fear by engaging the adrenal cortex and flooding the body with adrenaline, activating the so-called fight or flight response. But doubt, akin to despair, saps the body of all vigor, turns the blood cold, and extinguishes the fires of intention and action. It is immobilizing. Fear strikes suddenly, but doubt is a brooding phantom. It is fear that has been nursed and has become a mental crutch, and just as you must abandon the crutch in order to walk fully erect and unencumbered naturally, you must abandon the crutch of doubt if you are to navigate along this long and uncertain path.
If you’ve been at this oldpremed thing for any length of time, or have given serious consideration to the task you are preparing to undertake than you already know that this race, to again borrow language from the ancients, “is not given to the swift, neither to the strong,†but to him or her who will endure until the end. In order to make it to that proverbial end, however, you must first understand the nature of and then eradicate any shred of doubt—not once and for all, but continually. Armor your mind with whatever weapon you can find or assemble and the moment that you are besieged with the enemy of doubt vanquish it or, count on this, it will vanquish you.
Indeed. He hasn’t destroyed me yet. I hope he never will. But right now, after failing a chem class doubt is one step ahead of me 
Good post.
Wow, what excellent and informative post!!!
Thanks.