All three of these qualities get their focus from what the Buddha called yoniso manasikara, appropriate attention. Notice: That’s appropriate attention, not bare attention. The Buddha discovered that the way you attend to things is determined by what you see as important: the questions you bring to the practice, the problems you want the practice to solve. No act of attention is ever bare. If there were no problems in life you could open yourself up choicelessly to whatever came along. But the fact is there is a big problem smack dab in the middle of everything you do: the suffering that comes from acting in ignorance. This is why the Buddha doesn’t tell you to view each moment with a beginner’s eyes. You’ve got to keep the issue of suffering and its end always in mind.
Otherwise inappropriate attention will get in the way, focusing on questions like “Who am I?” “Do I have a self?”—questions that deal in terms of being and identity. Those questions, the Buddha said, lead you into a thicket of views and leave you stuck on the thorns. The questions that lead to freedom focus on comprehending suffering, letting go of the cause of suffering, and developing the path to the end of suffering. Your desire for answers to these questions is what makes you alert to your actions—your thoughts, words, and deeds—and ardent to perform them skillfully.
Mindfulness is what keeps the perspective of appropriate attention in mind. Modern psychological research has shown that attention comes in discrete moments. You can be attentive to something for only a very short period of time and then you have to remind yourself, moment after moment, to return to it if you want to keep on being attentive. In other words, continuous attention—the type that can observe things over time—has to be stitched together from short intervals. This is what mindfulness is for. It keeps the object of your attention and the purpose of your attention in mind.
Popular books on meditation, though, offer a lot of other definitions for mindfulness, a lot of other duties it’s supposed to fulfill—so many that the poor word gets totally stretched out of shape. In some cases, it even gets defined as Awakening, as in the phrase, “A moment of mindfulness is a moment of Awakening”—something the Buddha would never say, because mindfulness is conditioned and nirvana is not.
These are not just minor matters for nitpicking scholars to argue over. If you don’t see the differences among the qualities you’re bringing to your meditation, they glom together, making it hard for real insight to arise. If you decide that one of the factors on the path to Awakening is Awakening itself, it’s like reaching the middle of a road and then falling asleep right there. You never get to the end of the road, and in the meantime you’re bound to get run over by aging, illness, and death. So you need to get your directions straight, and that requires, among other things, knowing precisely what mindfulness is and what it’s not.