|The Human Brain, Home of our existence and the Writer of our stories.|
“What if I told you that this world around us, this richly textured world, were all just an illusion constructed in your head?” asks eminent neuroscientist David Eagleman in the brilliant documentary The Brain with David Eagleman.1 He then questions, “What if I said that the real world has no smell or taste or sound? What if I said there’s no color?” and then concludes, “If you could perceive reality as it really is out there, you wouldn’t recognize it at all.” Indeed, this richly detailed world that we see around us and experience every day is in fact one of the marvelous constructs of our brain.
The human brain, weighing around three pounds and residing in our skulls, is the home to our very existence. Though isolated from the physical world, our brain provides us with the ability to perceive reality through our sensory modalities.1 This idea is expressed further by neuroscientist Anil Seth in his 2017 TED talk titled “Your brain hallucinates your conscious reality.” According to Seth “our conscious experiences of the world around us, and of ourselves within it, are kinds of controlled hallucinations that happen with, through and because of our living bodies…. We don’t just passively perceive the world, we actively generate it… When we (collectively as a society) agree about our hallucinations, we call that reality.”2 This phenomenon of the brain generating our reality has fascinated neuroscientists of all generations with modern neuroscience continuing to illuminate many new facts about ourselves every day.
We use our brain without giving it much thought. Only if a function of one of its regions is lost do we truly understand the devastating effects it can have on human lives. This is brought out by the curious case of Charles Joseph Whitman.
Whitman was an engineering student at the University of Texas. On August 1, 1966, Whitman murdered his wife and mother.3 He then headed to the University of Texas at Austin, where, after climbing the tower, he started shooting at innocent civilians, killing fourteen people before he was shot down.3
What makes this case even more curious is Whitman’s suicide note, in which he wrote, “I do not really understand myself these days. I am supposed to be an average reasonable and intelligent young man. However, lately (I cannot recall when it started) I have been a victim of many unusual and irrational thoughts.”4 He also requested an autopsy be done on him after his death to find any visible physical disorder.4 His wish was granted.
On autopsy, Whitman had a tumor of the brain known as glioblastoma multiforme, which was impinging on a region of the brain known as the amygdala.5 The amygdala affects decision making and the processing of emotional reactions and the tectonic shifts in his character were likely due to this tumor.5
This example points out how the thinking mind cannot be separated from the physical brain. Outside of the field of science, philosophers have also wrestled with this concept. Descartes was one of the strongest proponents of what is referred to as Dualism in the philosophy of mind, and believed an immaterial soul residing in the pineal gland was exercising its functions over the rest of the body. He detailed this concept in his famous Meditations on First Philosophy and Passions of The Soul.6,7 Cartesian Dualism did have its critics, even in the era of Descartes. A modern criticism is the lack of evidence of any immaterial soul affecting the workings of the physical brain.8
Many other approaches have been taken to tackle the problem, such as the Identity Theory, which identifies mental states – thinking, feeling etc. – as being causally linked to brain processes e.g. pain being equivalent to C-fibers firing.9 Another influential theory, Functionalism, compares the brain to a computer in which mental state depends on the inputs it receives (stimuli) and the output it gives (our responses to these stimuli).10
Yet to be tackled is the problem of consciousness. The philosopher Thomas Nagel very rightly wrote in his famous 1974 article, What is It Like to Be a Bat? that “Without consciousness, the mind-body problem would be much less interesting. With consciousness, it seems hopeless.”11 The philosopher David Chalmers described our conscious experience beautifully in 2014 when he said, “Right now you have a movie playing inside your head. It’s an amazing multi-track movie. It has 3D vision and surround sound for what you’re seeing and hearing right now, but that’s just the start of it. Your movie has smell and taste and touch. It has a sense of your body, pain, hunger, orgasms. It has emotions, anger and happiness. It has memories, like scenes from your childhood playing before you. And it has this constant voiceover narrative in your stream of conscious thinking. At the heart of this movie is you, experiencing all this directly. This movie is your stream of consciousness, the subject of experience of the mind and the world.” 12
According to David Chalmers, the problem of consciousness is that it involves a subjective experience, being not like lightning, which can be objectively explained as the movement of charges.12 The real problem is how neural firings inside our physical brain give rise to this rich inner movie we experience as consciousness.12
Chalmers takes a radical approach to the problem. He suggests that consciousness is a fundamental building block of the universe, like mass, space, or time. This would not do away with applying scientific method to consciousness, but rather help open new scientific approaches to dealing with this mysterious phenomenon. He believes we would then have to figure out the fundamental laws governing consciousness just like the physical laws governing mass, space and time, opening a new dimension into the exciting research being done on this topic.12
Whatever the solution, objective or not, who we are has always remained a fascinating mystery. Indeed, we must stop and wonder, what a magnificent organ resides in our skulls that not only generates our reality but grants us the ability to question it at the same time. Truly mesmerizing.
- The Brain with David Eagleman 2015.
- Seth A. Your brain hallucinates your conscious reality 2017.
- Books. T-L. Mass murderers. Alexandria, Va.: Time-Life Books; 1993.
- Whitman C. Whitman Letter. Austin American Statesman: Austin American Statesman; 1966.
- Report to the Governor, Medical Aspects, Charles J. Whitman Catastrophe. Austin American Statesman1966.
- Descartes R, Cottingham J. René Descartes: Meditations on first philosophy: With selections from the objections and replies. Cambridge University Press; 2013.
- Descartes R. The passions of the soul. Hackett Publishing; 1989.
- Scott C. Dualism and Mind Internet Encyclopedia of Philosophy Iep.utm.edu.
- Smart JJ. Sensations and brain processes. The Philosophical Review. 1959:141-156.
- Putnam H. The nature of mental states. Readings in philosophy of psychology. 1980;1:223-231.
- Nagel T. What is it like to be a bat? The philosophical review. 1974;83(4):435-450.
- Chalmers D. How do you explain Consciousness? 2014.
JALEED AHMED GILANI, MBBS, is a recently graduated doctor from Ziauddin University, Karachi, Pakistan and has a deep interest in clinical neuroscience.