The life of the mind is fragile. I have been constantly reminded of this from my time in academia. I have seen one academic after another fall prey to chronic fatique, and I learned only the other day from a brain expert that for academics, one can spend up to 75% of ones latent energy in brain work. This is why a person can completely tire out after only sitting in a chair and reading and thinking most of the day. Another aspect of this is that the mind is subject to the affective side of our lives, such that if there is a lot of emotional turmoil it become difficult not only to concentrate or focus but even just to think coherently. We are psychosomatic wholes, and we think too little about the effect of the mind on the body and vice versa. There is something to the saying 'as a person thinks, so they are' though this has degenerated into nonsense about thinking one's health issues away or 'the power of positive thinking' as if it were a panacea that culd cure all ills. It is the height of irony that Mary Baker Eddy who was one of the most unwell religious figures I know of of, touted the nonsense of mind over matter, or even illness is a mental illusion that we hear in American culture from time to time.
But there is another side to this-- namely that God has put eternity in our minds, so we will not be content with the temporal. Several small things seem to point to this. Have you noticed how when you havent seen a person for a long time and then see them again you are surprised to find them different or aged or both? Your mental image of them has not changed, even though you know rationally they have aged. Why? Or again the siren song of the brain tells us we can do things that we actually could only do when much younger. I call this the mind writing checks the body can no longer cash. It happens to me when I try to play sports, say basketball for instance. Afterwards, when I am sore and tired my body reminds my brain that I was way over optimistic about what I could manage.
The mind is something far greater than just the brain hardware, and it is truly amazing to study how the mind can rewire itself and restribute the work load when some of it has been damaged by stroke or disease. There is a sort of mental compensation faculty built in. And it is clear from Alzheimer studies that memory and remembering is a key to being a normal function person, or even to have a personality.
The ancient Egyptians were smart about many things, but not about the mind. They thought the grey matter of the brain was detritus and could be sucked out of the skull and thrown away while the internal organs were a key to the afterlife and needed to be mummified and preserved in canopic jars. The Hebrews thought that mind and the heart were intertwined. Sometimes they spoke of the thoughts of the heart, sometimes the thoughts of the mind, but the heart was seen as the control center of the personality, whereas we now know the mind is. Yet there is wisdom in what Carson McCullers used to say that the heart has 'reasons that reason knows not of'.
And finally what exactly did Paul have in mind when he exhorted us to have the mind of Christ? Its worth pondering.