What is mindfulness?

Kabat-Zinn, if you haven’t heard of him, is a famous teacher of mindfulness meditation and the founder of the Mindfulness-Based Stress Reduction program at the University of Massachusetts Medical Center.
First of all, mindfulness involves paying attention “on purpose”. Mindfulness involves a conscious direction of our awareness. We sometimes (me included) talk about “mindfulness” and “awareness” as if they were interchangeable terms, but that’s not a good habit to get into. I may be aware I’m irritable, but that wouldn’t mean I was being mindful of my irritability. In order to be mindful I have to be purposefully aware of myself, not just vaguely and habitually aware. Knowing that you are eating is not the same as eating mindfully.

Let’s take that example of eating and look at it a bit further. When we are purposefully aware of eating, we are consciously being aware of the process of eating. We’re deliberately noticing the sensations and our responses to those sensations. We’re noticing the mind wandering, and when it does wander we purposefully bring our attention back.

When we’re eating unmindfully we may in theory be aware of what we’re doing, but we’re probably thinking about a hundred and one other things at the same time, and we may also be watching TV, talking, or reading — or even all three! So a very small part of our awareness is absorbed with eating, and we may be only barely aware of the physical sensations and even less aware of our thoughts and emotions.

Because we’re only dimly aware of our thoughts, they wander in an unrestricted way. There’s no conscious attempt to bring our attention back to our eating. There’s no purposefulness.
This purposefulness is a very important part of mindfulness. Having the purpose of staying with our experience, whether that’s the breath, or a particular emotion, or something as simple as eating, means that we are actively shaping the mind.

Left to itself the mind wanders through all kinds of thoughts — including thoughts expressing anger, craving, depression, revenge, self-pity, etc. As we indulge in these kinds of thoughts we reinforce those emotions in our hearts and cause ourselves to suffer.
By purposefully directing our awareness away from such thoughts and towards some “anchor” we decrease their effect on our lives and we create instead a space of freedom where calmness and contentment can grow.
http://www.wildmind.org/applied/daily-life/what-is-mindfulness

You are not your thoughts. Our thoughts take us away from being here now. If I am thinking about the past, or worried about the future, I am a prisoner of my thoughts. When I take a moment to observe myself having thoughts, I am no longer the thoughts. I get to be and observe at the same time. That’s why if I continue to come back to my breath which always occurs in the here and now, it draws me into the present. And from that vantage point I can observe as past and future attempt to draw me away from the moment. This paying attention to the here and now, to the breath, to the observing one’s thoughts without being critical or judgmental is what many people call Mindfulness. But what is mindfulness?

Mindfulness is a word. Nothing more, nothing less. As a word it is a symbol or a sign. As a sign or symbol it points to a way of looking at life in general and one’s own life in particular. Mindfulness points one in the direction of being aware of the present moment.
Mindfulness points to: Being aware of and paying attention to the moment in which we find ourselves. Our past is gone, our future is not yet here. So what exist between them is the present moment. If I can observe and not get caught up in my thoughts, it is all that I have. The here and now, the present is the link which holds what was and what will be. My past was a series of present moments which brought me to this present moment. My future should it happen will be a series of present moments effected by only present moment in which I am now living, being, doing, observing, being aware or unaware, and attentive or unattentive.

While mindfulness is a generalization about paying attention and being aware in the present moment , it occurs only in the individual. That individual makes a choice to be in the moment and be aware of what is happening in the present moment. In that choice is a realization.
You are not your thoughts. Thoughts take us away from being here now. If I am thinking about the past, or worried about the future, I am a prisoner of my thoughts. When I take a moment to observe myself having thoughts, I am no longer the thoughts. I get to be and observe at the same time. That’s why if I continue to come back to my breath which always occurs in the here and now, it draws me into the present. From that vantage point I can observe as past and future attempt to draw me away from the moment.

This paying attention to the here and now, to the breath, to the observing one’s thoughts without being critical or judgmental is what many people call Mindfulness.
http://www.mindfulness.com/

Fundamentally mindfulness is a simple concept. Its power lies in its practice and its applications. Mindfulness means paying attention in a particular way: on purpose, in the present moment, and nonjudgmentally. This kind of attention nurtures greater awareness, clarity, and acceptance of present-moment reality. It wakes us up to the fact that our lives unfold only in moments. If we are not fully present for many of those moments, we may not only miss what is most valuable in our lives but also fail to realize the richness and the depth of our possibilities for growth, and transformation.
— “Wherever You Go, There You Are” by Jon Kabat-Zinn. p.4

The millions are awake enough for physical labor; but only one in a million is awake enough for effective intellectual exertion, only one in a hundred millions to a poetic or divine life. To be awake is to be alive. I have never yet met a man who was quite awake. How could I have looked him in the face? We must learn to reawaken and keep ourselves awake, not by mechanical aids, but by an infinite expectation of the dawn, which does not forsake us in our soundest sleep.
— “Walden” by Henry David Thoreau.

I am learning slowly to bring my crazy pinball-machine mind back to this place of friendly detachment toward myself, so I can look out at the world and see all those other things with respect. Try looking at your mind as a wayward puppy that you are trying to paper train. You don’t drop-kick a puppy into the neighbor’s yard every time it piddles on the floor. You just keep bringing it back to the newspaper. So I keep trying gently to bring my mind back to what is really there to be seen, maybe to be seen and noted with a kind of reverence.
— “Bird by Bird” by Anne Lamott

So, mindfulness will not conflict with any beliefs or traditions — religious or for that matter scientific — nor is it trying to sell you anything, especially not a new belief system or ideology. It is simply a practical way to be more in touch with the fullness of your being through a systematic process of self-observation, self-inquiry, and mindful action. There is nothing cold, analytical, or unfeeling about it. The overall tenor of mindfulness is gentle, appreciative, and nurturing. Another way to think of it would be “heartfulness.”
— “Wherever You Go, There You Are” by Jon Kabat-Zinn. p.6