No problem can be solved from the same level of consciousness that created it. ~ Albert Einstein
Mindfulness meditation is simple to explain and difficult to practice.
One popular type of mindfulness mediation is when we learn to observe our thoughts. But what does it entail to be able to observe our thoughts? And what does it imply to watch thoughts pass through our mindscreens as if they are clouds drifting through the sky? It entails a WATCHER that has some distance from those thoughts and is able to observe them impartially. And this implies that we have a CORE SELF that is not comprised of our thoughts, or at least not solely by thoughts.
What is the core self that is able to watch our thoughts? Is it something spiritual, such as a higher power? A soul? An atman? Or is it a state of being, such as samadhi, nirvana, or moksha? Or is it something divine, such as God, Ein sof, Brahman, Krishna, or universal consciousness? What about a collective unconscious? Or prana? Or love?
Maybe a better way to approach the problem is by rephrasing the question from a less spiritual and more scientific paradigm: How do we get the mind to look at the mind?
One interesting characteristic of the mind is that you cannot tell it what NOT to think about. For example, if I say, "Close your eyes. Now don't think of a pink elephant." What normally happens is that the mind puts an image of a pink elephant onto your mindscreen and then removes it.
Each time someone utters the command, "Don't think of X," our minds put X into our mindscreens and then remove it. Thus, it is easy to see why we cannot consciously weed out traumas and negatively-charged recollections from our memories. If/when our mind blocks a trauma, this is what Freud deemed a "repression," and it only occurs subconsciously. (I anticipate fellow therapists arguing that EMDR or a similar modality accomplishes something akin to "suppression," or some type of conscious reprogramming, but for most people it remains impossible to intentionally erase negatively-charged files from our mental hard drives. Just ask any diehard alcoholic.)
Must we trick the mind so that it somehow gets some insight into how it is operating?
The ancient spiritual tool of meditation (now commonly referred to as mindfulness meditation) was devised to take us beyond our thoughts and enable us to "realize" -- i.e., experience -- that we are essentially united with the divine. But we can also use this tool for its psychological effects because it allows us to temporarily dis-identify with our thoughts.
Descartes' Cogito Ergo Sum -- I think therefore I am -- proposes that we get our personal identities through our thoughts. This would not be entirely awful if our minds did not have a negativity bias.
But they do. A disproportionate percentage of our thoughts are negative.
Which is also why mindfulness meditation is such an effective psychological tool. Because by learning to impartially observe our thoughts, mindfulness meditation allows us to gain brief respites from the soundtracks in our heads. When we are able to dis-identify with our mental chatter -- even just for seconds at a time -- we are able to cultivate equanimity, peace, calm, tranquility, and non-reactivity.