“Our brain is simply a vehicle for formless awareness to function in form. It is kind and wise to learn to use it well.”
~ Kathleen Singh, The Grace in Aging, 121
1. Life Above All Else
The primary default function of our brain is to keep it and our body alive.
Almost everything the brain does, from winnowing down input from our senses so that 99% of what we encounter can be processed – albeit unconsciously, to the constant monitoring of the environment for threats, to the ongoing modulation of arousal states – these brain functions have all evolved with the primary purpose of keeping us alive. To the brain, death is perceived as the enemy, one to be kept at bay by almost any means necessary for as long as possible. To see the unfortunate consequence of this vulnerability of our collective brains, visit a senior care facility. Or watch crows when one of their own dies. Or better yet, read this account of what happens when a good neuroscientist’s brain goes bad.
To countermand this limitation of the brain – its inability to fathom the strangeness of unbeing – many spiritual traditions offer practitioners specific information about death. Often what’s offered is guidance for what practitioners can expect once the body dies. So, for example, Tibetan Buddhism offers The Eight Cycles of Dissolution as a description of what to expect upon leaving this life. Catholicism instructs that those who die in sin are dispatched to the Hell Realms, while those who die in God’s grace receive eternal salvation. Neuroscientists believe that something happens – The First Law of Thermodynamics applies – they’re just not sure what. And it may be different for every one of us, just as every one of our living brains and bodies are different.
But what happens to us while we’re living and our brain-built concerns about death genuinely become a non-issue? One measure of death as a non-issue might be our degree of self-transcendence. It turns out there are specific networked brain regions that correspond with our degree of self-transcendence. Might our personal concerns about dying dissolve into self-transcendence simply by organically rewiring those areas? And if so, how might we best go about that rewiring?
2. Our Brain Uses Words to Navigate the Consensus-Reality World
Between 18 to 24 months, the language areas of the brain become available for understanding and generating language. These are generally thought to be Broca’s Area and Wernicke’s Area, located in the left hemisphere (corresponding areas in the right hemisphere are thought to process the “Deep Structure” of language). How we learned these areas are associated with language understanding and generation was through research on patients who had Broca’s and Wernicke’s areas damaged. 
People who are unable to understand written or spoken language are diagnosed with Wernicke’s Aphasia. We are able to put thoughts into words and generate speech courtesy of Broca’s Area, which is considered the brain’s scriptwriter. When Broca’s area is damaged, we lose the ability to express language.
Once language comes online, it mediates direct contact with the world. We begin to attach words to people, places and experiences. We begin to construct a life-narrative. That narrative uses words which store easily as memories. Those memories and that narrative begin to define – and significantly limit – who we think we are. Who would we be without our personal narratives, our unique personal histories? Especially since much of what our brain is designed to pay most attention to are people, places and experiences where hyper-arousal or threats to life are involved, making them all most memorable.
3. Our Brain Constantly Time Travels.
In the 1970’s the comedian Flip Wilson made The Church of What’s Happening Now a national meme. Members of the church lived life according to The Ram Dass Principle: Be Here Now. Divinity/Spirituality can only be found in the now – in the present moment. Unfortunately, thanks to the Prefrontal Paradox (email me – floweringbrain@gmail.com – if you’re interested in the explanatory slideshare), many of our brains lack sufficient bandwidth and connectivity to continually take up residence in The Church of What’s Happening Now. 
In order to keep us alive, the brain generates all kinds of words that either take us back to the past or have us thinking about the future in ways intended to insure our survival. It generates thoughts like: How can I make more money? How can I get healthier? How can I have more friends? How can I learn more about spirituality and the brain?– all oriented towards making things different and hopefully better and contributing to a longer life at some time in the future.
So, there you have three ways the brain undermines spirituality. If you want a few hundred more, here’s a link to a dozen recent books on Neuroscience & Spirituality. They’re filled with words about death and a better future that you may find to be an interesting distraction. I certainly did.
Oh, and lest I forget, here’s another Enchanted Loom on spirituality – my friend, Kathleen Singh’s wonderfully readable book, The Grace in Aging.
Catholicism doesn’t see the Hell realms as being after death but exists now. Eternal life is also now – not something which will happen after death. Perhaps you might want to consider the insights of Mystical Theology in contributing to this theme. Sin in Catholicism is only considered to be “missing the mark”. The mark is unconditional love. We are created from love and are born to act from love but we are “crucified” in our stage of evolution between having being seeded with a desire for the “Divine” and yet controlled by the unconscious needs of the false self – power, control, needs for approval, respect, security and survival – all driven by our instinctive unfulfilled emotional needs.
I very much like the reference you make to the thinking mind takes us away from reality and who understanding who we are – our spiritual dimension and only reality in being.
Thanks, Dierdre, for taking the time to post. One revelation I’ve taken away from a number of the brain and spirit books on the list is that there is really no such thing as Catholicism (or Buddhism, or Judiasm, etc). There are only individual people, each interpreting and practicing their own unique take in any moment on this thing they identify Catholicism, Buddhism, Judiasm, etc.