(The more I study this topic the more I find how daunting it is. So I see I'm pretty ambitious with this undertaking. I could have just put a link to other MUCH better articles, from MUCH more established writers. Buuuut this gives me a chance to process these concepts. And it also gives others out there a sense of how I think about - and teach on - mindfulness.)
I find it interesting that there is not a universally agreed upon definition of mindfulness. Probably because it is meant to be directly experienced through one’s own body, mind, and sense faculties. Since everyone’s direct experience does and will vary, a dictionary definition is really just a sign post pointing toward a felt experience of mindfulness. Yet, we all must start somewhere.
Here are three definitions of mindfulness, (One, a modern-day psychological definition, and the others come from two traditional Buddhist texts) and my brief commentary on each one.
Mindfulness-Based Stress Reduction (Jon Kabat- Zinn) says...
...Mindfulness is the awareness that arises from paying attention on purpose in the present moment non-judgmentally.
I feel this is a great entry-way into understanding mindfulness. It covers a lot, and one can get "far" with just these instructions. However, it can be misleading if you one does not inquire further. Common questions arise, such as "How does the act of planning fit into this if I'm just supposed to be in the moment all the time?" or "If I'm being non-judgmental, how do I make sure I don't become a door mat?" Note Kabat-Zinn's own extrapolations on this definition do a good job of addressing these questions and many more. So I'm not faulting him at all for not including them in his definition. Just bringing mindfulness to the number of judgements we make in a day can be very insightful. So to live in the present, non-judgmentally is no small order!
Let's see what some older texts say about mindfulness
Nagasena was an Indian Buddhist
scholar and awakened being who lived around 150 BCE. He has a longer definition that sounds much different and gets more at the quality of discernment and ethical behavior.
Mindfulness, when it arises, calls to mind wholesome and unwholesome tendencies, with faults and faultless, inferior and refined, dark and pure, together with their counterparts....mindfulness follows the courses of beneficial and unbeneficial tendencies: these tendencies are beneficial, these unbeneficial; these tendencies are helpful, these unhelpful. Thus, one who practices yoga [meditation, in this context] rejects unbeneficial tendencies and cultivates beneficial tendencies. (I plucked this from B. Alan Wallace's wonderful YouTube video, "The Buddhist Science of Mind" Day 1, time-stamped ready to watch here for your convenience if you'd like to hear his comments on this definition.)
Again, though he doesn't say it outright, he implies what Kaba-Zinn states plainly: PAY ATTENTION. Pay attention to the skillful and unskillful components of your behavior. Because that's why most of us come to mindfulness anyway, right? To change our behavior in some way. So Nagasena is saying, to change your behavior, you must understand the positive and negative sides of it well. We must understand clearly what we do that causes our own suffering, and what we do that doesn't. This is more difficult than it seems.
So, authentic mindfulness not only has us paying attention to our body, speech, and mind now, in the moment. It also requires us to bear in mind (and this is another important definition of mindfulness, to bear something in mind) the potential outcomes for our present behavior. This could be called "prospective mindfulness." So mindfulness is not just about what's happening now, but also about being mindful of what may come in the future. Likewise for the past and reflection, or "retrospective mindfulness." Because even thoughts of the past and future are happening NOW, aren't they?
The last definition comes from the classic must-read Buddhist text on the 4 Foundations of Mindfulness, said to have been spoken by the historical Buddha himself (translation by Thanissaro Bhikkhu) over 2,500 years ago. Here he highlights aspects of mindfulness that can often be overlooked, aspects that go beyond just being "in the now." (I've edited for pronouns/gender to be more inclusive) Oh, and this is the refrain to the text, so this is from the section on mindfulness of the body.
"There is the case where a practitioner remains focused on the body in & of itself — ardent, alert, & mindful — putting aside greed & distress with reference to the world...their mindfulness that 'There is a body' is maintained to the extent of knowledge & remembrance. And they remain independent, unsustained by (not clinging to) anything in the world. This is how a practitioner remains focused on the body in & of itself."
Here he is emphasizing in this refrain of the text that mindfulness ought not be separated from ardency and alertness. It is not a time to "zone out" when we practice meditation. When we focus our attention on an object, we are right there with the object without adding additional commentary, opinions, judgements, critiques, and so on. When the mind wanders, we are alert enough to notice ardent enough to bring our attention back lest we fall in passive mindfulness. Somewhat like a game of mental "whack-a-mole." Mindfulness is also entwined with non-greed and non-hatred to anything in the world (putting aside greed & distress with reference to the world). Even if we are purposefully being present, if we are wanting our experience to be different than it is, then it's not true mindfulness. Presence, attention, and also acknowledgement on their own is not mindfulness. This is why from mindfulness teachers you hear almost ad nauseum the instruction to remain with your experience, "as it is...as it is." It's a powerful instruction in just six letters.
Additionally, I've found that as we remain with things as they are we strengthen the quality of discernment. Thus, we are more prepared to take Nagasena's advice and bear in mind the wholesome and/or unwholesome results of our present actions or inactions. We know when to be with things as they are and we know when we must take action (e.g. shift our posture, add more salt to the soup, or make that difficult phone call). This means that mindfulness becomes the thread that ties seamlessly together the fabric our life, whether we are sitting or moving. I can move quickly to get to a work meeting, while still bringing mindfulness to the experience of moving quickly, or rushing even. So the totality of our experience - thoughts, feelings, and physical sensations - are fair game for mindfulness to arise to the fore.
If these last two definitions feel a bit more difficult to grasp or lofty, mindfulness practice doesn't have to be. We can look around. Notice the light and colors. Take a moment to listen to sounds, whether near, far, clear or faint. Feel our bodies, toes, and the delicate way our clothes rest upon our skin. Objects of smells and tastes of course are not excluded from ways to infuse mindfulness into our lives. Finally, thoughts and feelings are present in the moment as well. Whether its internal dialogue or a subtle feeling of anxiety because you're reading this and it's past your bed time. Whatever you're experiencing, either through your senses (seeing, feeling, hearing, smelling, and tasting) or within your own mind, THAT is your present moment experience, your life! It's possible to rest right there.
Mindfulness practice can be profoundly simple and overwhelmingly expansive. Joseph Goldstein wrote a 422 page book on mindfulness, appropriately titled, Mindfulness. So the path is yours and yours alone. Whether a one-sentence definition suffices for you or a 422 pager does, it is really about what is helpful for you.
I hope this article was helpful for you.