How we pay attention to the present moment largely determines the character of our experience and, therefore, the quality of our lives.
Although the claim seems to annoy believers and atheists equally, separating spirituality from religion is a perfectly reasonable thing to do. It is to assert two important truths simultaneously: Our world is dangerously riven by religious doctrines that all educated people should condemn, and yet there is more to understanding the human condition than science and secular culture generally admit.
Some well-established truths about the human mind: Our conventional sense of self is an illusion; positive emotions, such as compassion and patience, are teachable skills; and the way we think directly influences our experience of the world.
It seems to me that I spend much of my waking life in a neurotic trance. My experiences in meditation suggest, however, that an alternative exists. It is possible to stand free of the juggernaut of self, if only for moments at a time. A true spiritual practitioner is someone who has discovered that it is possible to be at ease in the world for no reason, if only for a few moments at a time, and that such ease is synonymous with transcending the apparent boundaries of the self.
Unlike the doctrines of Judaism, Christianity, and Islam, the teachings of Buddhism are not considered by their adherents to be the product of infallible revelation. They are, rather, empirical instructions: If you do X, you will experience Y. The teachings of Buddhism and Advaita are best viewed as lab manuals and explorers' logs detailing the results of empirical research on the nature of human consciousness.
It is true as a matter of conscious experience that the reality of your life is always now.
Being mindful is not a matter of thinking more clearly about experience; it is the act of experiencing more clearly, including the arising of thoughts themselves. Mindfulness is a vivid awareness of whatever is appearing in one's mind or body--thoughts, sensations, moods--without grasping at the pleasant or recoiling from the unpleasant. With practice, mindfulness becomes a well-formed habit of attention, and the difference between it and ordinary thinking will become increasingly clear. Eventually, it begins to seem as if you are repeatedly awakening from a dream to find yourself safely in bed. No matter how terrible the dream, the relief is instantaneous. And yet it is difficult to stay awake for more than a few seconds at a time.
From the contemplative point of view, being lost in thoughts of any kind, pleasant or unpleasant, is analogous to being asleep and dreaming. It's a mode of not knowing what is actually happening in the present moment. It is essentially a form of psychosis. Thoughts themselves are not a problem, but being identified with thought is. Taking oneself to be the thinker of one's thoughts--that is, not recognizing the present thought to be a transitory appearance in consciousness--is a delusion that produces nearly every species of human conflict and unhappiness. The feeling that we call "I" is itself the product of thought. Having an ego is what it feels like to be thinking without knowing that you are thinking.
Scientific research on the various types of meditation is just beginning, but there are now hundreds of studies suggesting that these practices are good for us. Again, from a first-person point of view, none of this is surprising. After all, there is an enormous difference between being hostage to one's thoughts and being freely and nonjudgmentally aware of life in the present. To make this shift is to interrupt the processes of rumination and reactivity that often keep us so desperately at odds with ourselves and with other people. No doubt many distinct mechanisms are involved--the regulation of attention and behavior, increased body awareness, inhibition of negative emotions, conceptual reframing of experience, changes in the view of "self," and so forth--and each of these processes will have its own neurophysiological causes. In the broadest sense, however, meditation is simply the ability to stop suffering in many of the usual ways, if only for a few moments at a time. How could that not be a skill worth cultivating?
For beginners, I usually recommend a technique called vipassana.
Gradual Versus Sudden Realization
Dualistic mindfulness--paying attention to the breath, for instance--generally proceeds on the basis of an illusion: One feels that one is a subject, a locus of consciousness inside the head, that can strategically pay attention to the breath or some other object of awareness because of all the good it will do. This is gradualism in action. And yet, from a nondualistic point of view, one could just as well be mindful of selflessness directly.
The whole of Advaita reduces to a series of very simple and testable assertions: Consciousness is the prior condition of every experience; the self or ego is an illusory appearance within it; look closely for what you are calling "I," and the feeling of being a separate self will disappear; what remains, as a matter of experience, is a field of consciousness--free, undivided, and intrinsically uncontaminated by its ever-changing contents.
Dzogchen: Taking the Goal as the Path
The practice of Dzogchen requires that one be able to experience the intrinsic selflessness of awareness in every moment (that is, when one is not otherwise distracted by thought)--which is to say that for a Dzogchen meditator, mindfulness must be synonymous with dispelling the illusion of the self. After I was introduced to the practice of Dzogchen, I realized that much of my time spent meditating had been a way of actively overlooking the very insight I was seeking.
Dzogchen is not vague or paradoxical. It is not like Zen, wherein a person can spend years being uncertain whether he is meditating correctly. The practice of recognizing nondual awareness is called trekchod, which means "cutting through" in Tibetan, as in cutting a string cleanly so that both ends fall away. Once one has cut it, there is no doubt that it has been cut. I recommend that you demand the same clarity of your meditation practice.
Unfortunately, to begin the practice of Dzogchen, it is generally necessary to meet a qualified teacher. Tulku Urgyen is no longer alive, but I'm told that his sons Tsoknyi Rinpoche and Mingyur Rinpoche generally teach in his style, and many other Tibetan lamas teach Dzogchen as well.
The Paradox of Acceptance
Embracing the contents of consciousness in any moment is a very powerful way of training yourself to respond differently to adversity. However, it is important to distinguish between accepting unpleasant sensations and emotions as a strategy--while covertly hoping that they will go away--and truly accepting them as transitory appearances in consciousness. Only the latter gesture opens the door to wisdom and lasting change. The paradox is that we can become wiser and more compassionate and live more fulfilling lives by refusing to be who we have tended to be in the past. But we must also relax, accepting things as they are in the present, as we strive to change ourselves.