"Mind Over Matter" is how thought processes can influence our physical reality. To understand how this works, we need to define what "Mind" is and the relationship of Mind and thought to "Matter".
One definition of Mind I found online is, "the element of a person that enables them to be aware of the world and their experiences, to think, and to feel; the faculty of consciousness and thought". The Mirriam Webster Dictionary defines Mind as, "the element or complex of elements in an individual that feels, perceives, thinks, wills, and especially reasons". And the Free Online Dictionary calls the Mind, "The human consciousness that originates in the brain and is manifested especially in thought, perception, emotion, will, memory, and imagination." The brain is the human organ most often associated with consciousness and the Mind. However, this definition does not explain experiences such as remote viewing, near death experiences, psychic and paranormal phenomena, and past life memories. Research done on people who have had near death experiences has shown that the brain is inactive during the experience. Or, in the case of remote viewing, psychic, paranormal and past life memories, there is no way to explain how the information entered the brain to create the experience.
Another definition of Mind is that it is the space and time in which thought and feeling exists, and that the brain is an instrument that perceives thought and emotion and uses these elements to create what we experience as physical reality.
Your brain receives signals from your body - the five physical senses - and uses this information to create a 3D image in the Mind. This 3D image is what we experience as physical reality. One way to understand this is to look at how the eyes and brain work together to create vision. Light enters the eye through the pupil and lens. An upside down mirror image is received at the back of the eye. The brain must then take this image and turn it right side up. Also, the image created by the eye is like a photo taken by a camera. It is two dimensional. The brain must also interpret the signals from the eye and convert them to a 3D image. It is this 3D image, created by the brain, that you actually "see". seeing diagram
Humans have experiences that cannot be explained by activity in the brain. Therefore, the Mind must include the brain but not be limited by it. To understand how this can happen, let's take a look at what human thought and human emotion or feeling might be.
Human thought is a process that takes place in the Mind and gives shape or form to our experience. The form that thought takes includes things like words and images. What we call feeling or emotion is actually the substance that allows us to perceive the thoughtforms in our Mind. When we perceive something in our Mind, it is the substance or feeling that gives the thoughtform color, taste, texture, sound, etc.
Some call this "energy and information"; feeling being the "energy" or substance, and thought being the "in-formation".
Mind is the space-time that contains all potential and manifested thoughtform and feeling (or substance). We choose the thoughts and feelings that create our physical life experience - even the brain, which perceives our creations. Mind is "over" matter in the sense that all matter is contained within the Mind. Mind Over Matter can be a mind-boggling subject. I mean think about it. We perceive physical reality with the brain. But the only way to perceive the brain is with the brain. So the brain, and body, is itself a 3D image created in the Mind! How can we possibly know what is real?! Here is what I have learned from my own experience.
Within the Mind is the brain and body, and there is also a Heart. Heart with a capital "H" because I'm not just talking about the physical pump we have all seen pictures of.
This Heart has a zero point, and it creates a torroidal electromagnetic field that send energy and information to the brain and every cell in your body. This zero point seems to be "The Seat of the Soul" - the connecting point or gateway through which non-physical energy and information emerge into and manifests as our physical reality. When we say "mind over matter" what we are referring to is that matter is within us — within the Mind. We are more than Mind of course. We are not isolated bodies subject to the whim of external forces. Everything that we perceive within the Mind is within who we really are. And we can choose the thoughts and feelings that give substance to what we perceive.