Last year while teaching a month-long silent meditation retreat with several other vipassana teachers, we were faced with what to do about a yogi who was not fully participating. He wasn't showing up for the sittings or attending the dharma talks, and he was avoiding scheduling an individual interview. One of the retreat managers even observed him leaving the retreat center on two occasions. I volunteered to talk to him and assess whether he should be asked to leave.

When I inquired about his retreat experience, he told me that although he had been sick, the retreat had been going fine. But as we talked, his story became much more complex. He was suffering from an illness that doctors said would likely kill him in the next six months, and he had come to this retreat to try to make peace with his circumstances.

"Why then haven't you come into the hall or taken an interview with a teacher?" I asked, after expressing my sympathy for his condition. His answer was surprising. He had previously been hospitalized twice, each time not knowing if he would survive. During the first stay, his meditation practice had been immensely comforting. He had been in a room by himself with a window looking out onto a tree and had spent many hours meditating with nature as his object of concentration. During his second hospitalization, he shared a room with another patient. His view of the outdoors was blocked by a screen, and the other patient played the television and radio constantly. He tried repeatedly to meditate but couldn't calm his mind in that environment. He was an emotional mess the whole time he was there.

His family and friends, who had been inspired by his equanimity during his first hospitalization, responded to the frustration he felt during his second stay by urging him, "Just use that meditation stuff you did last time." As a result, he felt as if he had failed both himself and those he cared for. His confidence completely eroded, and he doubted himself and his ability to meditate.

He had hoped that coming to this retreat would restore his faith in himself. Instead he was so paralyzed with self-doubt that he could not participate. He did not feel worthy of going into the meditation hall. His doubt was leading him further into fear, which only brought about more uncertainty. His story was heartbreaking. The reason he had left the retreat was to go to a nearby hospital for his required twice-weekly injections. He had been too embarrassed to tell any of the teachers.

I told him how glad I was that he had come and that we would explore his doubt together. Over the next three days, we deconstructed doubt, seeing its many faces and the stories it creates. He began to understand that the emotional turmoil he experienced during the second hospital visit was due to circumstances and did not represent some measure of his worth or his meditation practice. After a lot of work, he came to see doubt for what it is and was able to break free from its insidious power. He was able to come into the sitting hall and do the practice, and once again he found comfort in meditating.

You too are most likely on intimate terms with doubt. Although your circumstances are probably not as extreme as this man's, you may be just as caught in its feverish grip. It is not wise to underestimate the power of doubt, for it is one of the major infections of modern life. It often moves stealthily, gradually worming its way into your nervous system.

Once doubt is established, it creates chaos in your mind. Because there is a tendency to identify with it, you become a person of doubt. The ensuing uncertainty can then lead to indecisiveness, powerlessness, or a feeling of being separated from your Self.

Faces of Doubt

Doubt presents many faces, some of which are quite subtle. You may experience it as nonspecific anxiety, as if there is something you have forgotten to do or have done incorrectly. Doubt may be felt, yet unrecognized, as exaggerated or everpresent distress over a decision you have to make, or a vague sense that you have failed or that life isn't as you thought it would be.

These subtle symptoms reflect the dilemma of modern life: the absence of feeling grounded in something greater than your own ego structure. It is for this reason that doubt is both an existential challenge and a spiritual hindrance.

The Buddha taught that doubt is one of five hindrances that arise in the mind, clouding your judgment, limiting your ability to act, and causing great emotional disquiet. The first is sensual desire of any sort; the second is aversion to a person, situation, or something about yourself. The third, sloth and torpor, is the inability to initiate action, while the fourth, restlessness, is just the opposite - the mind is so restless and anxious with worry that it cannot settle down. The fifth hindrance is doubt. I sometimes call doubt the mother of all hindrances because when it is in control of your mind, there is not enough energy to engage. You find you have no heart for facing difficulties.

Skeptical Doubt

All doubt is not the same. I have observed that there are at least three different kinds - skeptical, nihilistic, and reactive doubt - and they vary greatly in impact. Skeptical or inquiring doubt can often be beneficial. For instance, in many spiritual traditions you are encouraged to be skeptical of blindly accepting beliefs and to explore through your own direct experience what is true. "Be a lamp unto yourself," said the Buddha. Likewise, yogis in Patanjali's tradition in India still go into the forest to discover spirit for themselves, and the same is true of the Desert Fathers in the Christian tradition. Skeptical doubt in spiritual and psychological exploration, as in science, can be healthy and useful.

Inquiring doubt uses mindfulness for investigation. Mindfulness practice helps overcome doubt because it acts with the confidence that it is possible "to know," or be mindful of how things are in any given moment. Or if you encounter a situation where all you know is confusion, then with mindfulness at least you have the clarity to know that you do not know. This distinction between knowing and knowing you do not know is surprisingly grounding and can stop doubt from working its way into your nervous system.

This insight leads to the first step in working with doubt: cultivating "don't know mind," which dispels the myth that you are always supposed to know, never to be in doubt. Likewise, you can examine your mind to see if you have an expectation that you should be perfect, which prevents you from realizing that painful mistakes are part of living life. New knowledge creates new uncertainties, so that which is causing you doubt can be appreciated because it signifies new possibilities to learn about yourself.

Nihilistic and Cynical Doubt

The second kind of doubt is nihilistic, and its close relative, cynical doubt. You probably know someone who is caught in these types of doubts; they're negative, suspicious, convinced that everyone and everything is inherently flawed or exploitive. This is not genuine doubt; it is a belief system disguised as doubt. It is dogma. It is much easier to recognize in another than in yourself.

If you continue with your inner work, you inevitably encounter spiritual doubt. At some point you will be called upon to recognize that somewhere within you there exists the debilitating voices of nihilism and cynicism. They are there no matter how well they are hidden by your optimism and trusting nature. Even now they affect your thoughts in small and large ways, but as you open to deeper possibilities for yourself, they will become more active. Only by bringing into consciousness the part of you that disbelieves do you free yourself from doubt's unconscious power over you. You can explore the truth of this for yourself: Simply allow your voices of cynical and nihilistic doubt to sit on the cushion with you, and get to know them. Treat the hurt and fear you find fueling these voices with compassion and loving-kindness, but use your skeptical doubt as a tool to question the validity of the nihilism or cynicism.

Reactive Doubt

The third kind of doubt is a condition of the reactive mind, and it is the primary subject of the Buddha's teaching on hindrances. It comes up both in daily life and in cultivating the inner life. It can be doubt about your own ability or worth, that of others, the teaching, or your practice. When reactive doubt is present, it is very hard to ever get started, to commit, follow through, apply effort, or practice. The unresolved emotional, career, and lifestyle questions that plague you are the result of reactive doubt, which is why the work you do on the cushion directly translates to your daily life.

Reactive doubt arises from causes and conditions. It may be from disappointment, uncertainty, an experience of failure, or an old belief about yourself. What matters is that you realize it is impersonal: You are not that doubt; it is not you. It is simply a mental state that has arisen because the right conditions were present, just as a rainstorm is created when the proper elements are present. When the causes abate, both doubt and rainstorm dissipate on their own. Therefore it is helpful to understand the causes and conditions, to see them clearly, and to treat yourself kindly while they are present.

Use your mindfulness practice to recognize doubt as just doubt. Label it as a thought that is generating emotions and bodily sensations, and see how it starts to proliferate into many other thoughts and stories. Once you start to see doubt clearly, it breaks up the solidity of the experience and becomes much less formidable a mind-state. With mindfulness you come to see that all your doubts are waves of uncertainty about what is true now or in the future, which manifest as words, images, and bodily sensations.

It is crucial that you not believe stories your mind tells. Use doubt to doubt your own doubt. Adopt the mantra: "This doubt is neither me nor mine; it is impersonal. It arises from causes and conditions, and it will pass with the passing of those causes and conditions." Treat doubt as a messenger, a call for change, or an opportunity to practice living with uncertainty.

Understanding that doubt is impersonal and arises due to conditions leads you to a second insight: that clinging or grasping in the mind is what gives doubt so much power to overwhelm you. You may be resistant to this idea at first, arguing that it is the uncertainty that causes your mind to start contracting. But upon closer examination, you can see for yourself that doubt and grasping mind have separate origins, even though they are often present together. Grasping is the hopeless insistence that life be controllable according to your wants, while doubt is the uncertainty that arises because life is unpredictable and often painful. When the mind insists on control and refuses to surrender to the truth that doubt is an inevitable part of life, resistance, contraction, and clinging come into being as mind-states. And when the mind contracts, doubt changes from being an unpleasant discomfort to suffering.

The insight of the truth of grasping is vital to working with doubt. You can prove this to yourself by watching your own mind when doubt arises. You may discover that you demand assurance that if you risk what you value, you will be rewarded. You may find that you are unable to accept that much of life is unknowable or that you are filled with aversion to failure because of what others will think of you or how you will regard yourself. Each of these attitudes represents the mind contracting around uncertainty. Each in its own way seeks to deny that risk, failure, and not knowing the right thing to do are an intricate part of life. It is not possible to experience the joy and beauty of life without also embracing our ignorance, the frailty of our efforts, and the frequency of our failures. Once you begin to accept these difficulties as a condition of life, your tolerance for uncertainty grows. You become calmer when doubt arises, and you suffer much less. And best of all, doubt ceases to have so much control in your life.

Doubt is an unavoidable part of the life experience. The stories of spiritual masters are filled with doubt, as are the biographies of men and women who have been great contributors to society. It follows then that there is no reason to fall into self-judgment when your own doubt appears. The judgment just becomes one more story, yet another layer of doubt that will ultimately have to be released.

A third insight necessary for working with doubt is that life is always changing, so your sense of what is important and the nature of your abilities is always out of date. Therefore, your anxiety about the future is misplaced. Much of it is based on your past - who you once were and what you once perceived to be important. When the future arrives, you will most certainly be different, as will the circumstances of your life. Mark Twain once said: "My life has been filled with terrible misfortunes - most of which have never happened." This insight helps you to be at ease with your doubt, to take advantage of the energy of your anxiety without being caught in the stories your mind creates.

On meditation retreats when fear arises around doubt, I often suggest that yogis stay concentrated on what they do know, in addition to practicing mindfulness and compassion. But you can also do all these practices in your daily life. It may be as simple as following your breath, or it may mean staying with your honest wish for more clarity or peace in your life. In addition to observing the tendency of thought to proliferate, you can use humor to refuse to let doubt set your mood. Or give it a name and greet it by that name when it arises. Likewise, you can ask who it is that doubts. Also, whose voice is your doubting voice? Or if your doubt comes with lots of images, notice the existence of these internal movies and ask yourself: Who creates the images? Why are they to be believed?

It is critical to understand that once strong doubt takes hold in the mind, all your other anxieties will join in. You may have a strong feeling of uncertainty about your job or your relationship. Either of these would be difficult enough to work with on their own, but if you watch carefully, you will see that your mind flits to other anxieties, large and small - to your health, your self-worth, whether or not to purchase a new car, or when to take a vacation. Once you start to observe it closely, you may realize just how ridiculous the mind can be and how independent of your wishes it is.

The antidote for doubt is faith. Faith, from the view of direct experience of spiritual truth, is not the same as belief. As meditation teacher Sharon Salzberg says in her new book, Faith (Riverhead Books, 2002), faith is a verb, an active willingness to suspend judgment and to see for yourself what is true. You can overcome doubt by having faith in your teacher, the teachings themselves, the practice, or whatever it is that inspires you to action.

As you start to work with your doubts through mindful inquiry, you will find that you begin to have insights, and these insights will give you confidence. They are a verification of your faith that doubt can indeed be worked with. You will begin "to know that you know" and that you do not have to be defined by your doubts.

For some people there is another problem that might seem unimaginable, and that is doubt denial. One yogi once put it this way: "I have such a strong aversion to doubt that I can't even allow it to arise. I simply am unable to recognize when I am caught in doubt. What do I do?" The phenomenon of denying your own experience of doubt is surprisingly widespread. There is such a sense of fear that if you let doubt in at all, you will be overwhelmed; therefore, you never directly notice it.

Denial of doubt often gets reinforced by those around you. It may be because they need to believe in you as the strong one. By avoiding your doubt, they do not have to experience their own. There are certainly times when a healthy denial is called for because if you were to focus on how bad a situation looked, you would be frozen in place. So you deliberately look away. This is the skillful use of placing your attention.

But a sustained pattern of denial is not wise. It forces you not to look at the full range of possibilities. It allows you to continue getting in deeper when your intuition is telling you to stop, and it prevents you from being an authentic person. I have seen so many people do great damage to themselves and others because they denied their doubts.

Doubt Sensations

If you cannot recognize doubt, the thing to do is to pay attention to your bodily sensations. You will discover that your body reacts in recognizable ways when strong doubt arises. It may be fluttering in the stomach, burning of the eyes, or body tension as though you were resisting or pushing against a force. You may feel pinpricks in the palms of the hands or numbness somewhere in the body. Each doubt has its own energetic expression. It may manifest as lack of energy, anxiety, fuzzy thinking, vagueness, or not feeling very present.

Each person has different sensations, but they tend to reappear each time there is strong doubt. Once you've identified these sensations and energetic states, you can know when doubt is present and be mindful of it, without believing there is any need to do something about it. Once your nervous system realizes you can handle the truth of how things are, you will gain more facility at recognizing doubt.

Remember that doubt is not just a difficulty; it is also your ally. It is there to let you know that there is uncertainty, so that you can weigh your choices and be prepared for things not going well. Many times doubt is suggesting that you should change course or reconsider trust. Other times doubt is your conscience telling you that something wrong is going on - it may be a violation of your values, an ethical wrong, or it may be a transgression against spirit. This is particularly true when there is another person involved, and even more so if it involves business, political, or other organizational activity. When people try to manipulate you with fear or unreal promises, it is your healthy, skeptical doubt that is asking you to look again. In these instances you may fall into doubt denial because you do not want to pay the price of doing what you believe to be right.

Sometimes doubts can seem unceasing, causing you to become intensely discouraged. When this happens, it is sometimes fruitful to ask yourself: Am I clinging to an old view of myself or of how life is supposed to be? Does this view or attitude need to die? To allow such deep change, to go forward in the face of doubt, requires trust in life itself and great courage on your part.

The poet Rainer Maria Rilke put it this way: "We have no reason to mistrust our world, for it is not against us. Has it terrors, they are our terrors; has it abysses, these abysses belong to us; if there are dangers at hand, we must try to love them. . . . we must hold to the difficult, then that which now still seems to us the most alien will become what we most trust and find most faithful. . . . Perhaps everything terrible is in its deepest being something helpless that wants help from us" (Letters to a Young Poet, New World Library, 1992). Rilke is suggesting that we open to and trust in the mystery of life, even in those moments of our deepest, darkest doubts.

This is what the man on the retreat was able to do with his illness. He realized that his illness was not going to magically disappear, nor was there much possibility of avoiding pain and death in his future. But he had also discovered that despite his doubts about his ability to bear the future, the wonder of life was still available to him. The requirement is just to be present for what is arising in this moment - doubts included.