Many of us are concerned about trying to live in the present moment rather than being caught up in the past, living in memories, or dwelling on the future, with our plans, fantasies, and anticipations. But the bare fact is that there IS only the present moment and you cannot live anywhere else. All of our experiences of self and world arise exclusively through our senses - visual, auditory, or somatic, subjective or objective. And our sensory experiences can ONLY arise in the now. Where else COULD they arise? You can certainly experience a memory of a past event, but that memory arises in the present moment as a visual and/or verbal thought. It can have no other existence than as a present-moment sensory event. The same is true of our fantasies, plans, and anticipations of the future. Thoughts of the future exist now and only now. So the question is not "how can I live more in the present moment?" but rather why do we have the impression that we don't when there is, in plain fact, no other option? Let's try to answer that question in some different ways.
We get the impression that we have somehow exited the present moment when our (present moment) experience of mental talk, mental image, and emotional body sensations becomes overwhelming, drowning out other sensory streams (especially external sight, sound, and touch sensations) and drawing our full attention into the content of the narrative we weave about the remembered past and fantasy future world. We can call up compelling images and speech that we weave into a narrative of a past that is no more and a future that has not yet occurred, but we also evoke emotional body sensations to go with the show in mind space. When we imagine an emotionally charged event from the past or the future - say for example an angry interaction with someone - our bodies conjure up the correct associated metabolic changes. We actually mimic in the present moment, the physical changes that "go with" our memories and fantasies. It is this combination of the powerful imagination and the body's emotional habits that cause these seeming lapses into past and future to draw us into a state of trance-like semi-consciousness.
A fundamental insight that comes from careful, consistent examination of our perceptions of self and world is that our sense of a separate, static "thing" called a self or a personal identity is not what it seems. We habitually weave together the threads of sensory input into a fabric of a separate identity, stuck together with craving, aversion, and unconsciousness. One of the emergent perceived properties of this congealed illusory self is a sense of permanence, a sense of an enduring personality that travels from a past into a future. In the direction of the past we construct a narrative to codify our personal history, to preserve a sense of where we have been and what we have done, to create a kind of experiential wake in the world. In the direction of the future, we project plans, fantasies, and expectations about the world and our place in it. Of course these narratives about the past and expectations of the future can only exist as sensory experiences in the present moment. But because we attach to them emotionally, they have an inordinate power to compel our attention to the point where we lose the ability to experience them as the present moment sensory experiences they truly are. It is rather like an hypnotic trance in which we imagine ourselves inhabiting our mental constructs of a durable self identity existing in a past and future.
Let's look at it from another angle. In his book Maps of Meaning, J.B. Peterson wrote the following:
"The unknown surrounds the individual, like the ocean surrounds an island, and produces affect, compels behavior, whenever it shows its terrible but promising face. Culture is constructed in spite of (in cooperation with, in deference to) this omnipresent force, and serves as a barrier, quelling emotions, providing protection against exposure to the unbearable face of God."
You can replace the word "culture" in this quote with "sense of static personal identity" and the statement remains perfectly true and relevant to our inquiry here. All of our sensory experience is unfolding in the present moment out of the great unknown. We have no way of actually KNOWING what that omnipresent unknown holds for us in even the next second. It could be some kind of tremendous benefit or it could be some tragedy. Both possibilities always exist. A big part of our success as a species derives from our ability to make some predictions about what is likely to emerge from the unknown. We really are not very good at it, in an objective sense, but we try to convince ourselves in hindsight that we are because it is comforting. The unknown is frightening and believing that we have some kind of handle on predictions, that we have a reliable set of expectations, for the future makes things less frightening. So we develop an emotional attachment to our perceived understanding and memory of what happened in the past (though it is always just a pale shadow of the reality) and to our expectations and predictions of the future (no matter how bad our track record). Because we have such strong emotional attachments to our "knowledge" of past and future, it is easy for those thoughts and emotions to dominate our sensory experience, making it seem as if we have somehow occupied the past or the future in our minds. And yet, all of our narratives and things we "know" about the past, and all of our expectations and predictions for the future exist ONLY as sensory events in the present moment.
We can also think about this in terms of Perceptual Control Theory (PCT). According to PCT, we all develop and maintain a vast, multi-level internal model of what self and world SHOULD be like - from the very basic sense of what it should feel like to stand vertically without falling over to the very abstract and complex sense of what it should feel like to be respected by your peers. We constantly compare the internal model of what our experience of self and world "should" be with what we are actually detecting in our sensory experience in the present moment. It is a vast network of negative feedback loops. As long as the internal model and actual sensory experience match, the system is quiet. But if the actual sensory experience in the present moment doesn't match the internal model, an error signal is generated that motivates action intended to correct actual perception so that it matches the internal model. If, for example, your inner ear detects your posture deviating from the (expected) vertical, an error signal is generated that induces the muscles in your feet and legs to adjust their tension until the perception of your posture matches the internal model of verticality. The same system operates at all levels of perception and the corresponding internal model. When the error signals arise, that generates a feeling of discontent, if at low intensities, or outright terror at high intensities (imagine the effect of the perception of being unable to breathe). If the trigger sensitivity is habitually too low and/or the error signal intensity is habitually too high, we suffer unnecessarily over perceptions that don't match our internal model. The result is a high level of emotional attachment to the internal model of what self and world are supposed to be like. Consequently, the sensory experience of the internal model and its error signals begins to predominate over the other sensory experiences of the moment. And because the internal model is necessarily based on past remembered experience and necessarily concerns itself with expectations about what the unfolding world should be, this hyper-focus on an overly sensitized internal reference model and its negative feedback systems creates an impression of being "out" of the present moment
Why does it matter? First of all, just as a matter of personal mastery, we should be able to focus our attention where we want it and be able to ignore aspects of sensory experience that are not serving our purposes. In my own history, one of the events that pushed me into a serious mindfulness practice was frustration with this lack of concentration power. I was on a hike in a beautiful natural environment but my attention kept drifting into an internal narrative, making it difficult for me to enjoy what I really wanted to enjoy. The habit of being drawn into memories, plans, fantasies, etc. detracts from the fulfillment available with a fully-conscious engagement with the presently unfolding world.
Additionally, our memories of the past are not very accurate. They tend to be highly truncated, distorted, and biased towards negativity (which do you remember more clearly, all of the nice things people have said to you or the mean ones?). And our expectations, plans, and fantasies of the future tend to be inaccurate as well. Both memories and plans for the future also tend to arise in a highly repetitive, redundant manner, which is usually just a waste of our attention.
But most importantly, it is within that semi-trance state in which we identify most deeply with the illusion of the static, separate "thing" called a self or personal identity that we suffer the most. So what to do? Practice mindfulness of course! But how does that help? In a number of different ways.
When we build out concentration power, we are better able to focus on whatever aspect of our current sensory experience we deem to be relevant. That might be a memory, plan, or fantasy. But it might be the scenery in front of our eyes, or the voice of the person talking to us, or the feeling of a loving touch. Concentration power allows us to choose.
Our sensory clarity practice increases the richness, the complexity, the volume of our sensory experience as it is unfolding moment by moment. As this process matures, the sights and sounds of the world around us, and our body sensations (emotional and not) begin to occupy ever more "space" within the finite capacity of our perceptual circuitry, relative to our mental constructs, leaving less and less opportunity for a sense of separate self, with its illusory duration in time, to fixate. In other words, as our experience of the unfolding world in all of its glory grows, there is less room for a compelling internal narrative.
Elsewhere on this site I have discussed in some detail how the succession of traumas large and small in our lives contribute to a network of emotionally reactive scar tissue that distorts out perceptions, interferes with our fulfillment, and drives us to unskillful action. It is also the source of the emotional "juice" that helps to make the memories, plans, fantasies, judgements, opinions, etc. so compelling, so able to "fix" us and turn us into sleepwalkers. As we systematically turn the light of consciousness inward and greet whatever arises with equanimity we sooth, heal, and release the stored trauma and in so doing, drain away from our internal narrative the power to fixate us.
And so, through our practice of mindfulness, we restore thinking processes to their proper place as useful tools rather than distracting, annoying, misleading, and hypnotic influences.