What Is Consciousness?
Consciousness is that little voice in your head that says, “Hey, I exist.” Not the voice that reminds you to buy milk or tells you your ex’s new haircut looks like a failed hedge sculpture, the deeper one. The voice that knows you are you. Without it, you are just a well dressed houseplant with a credit card.
Ancient and Historical Views
Humans have been trying to pin down consciousness for as long as we have had enough of it to realize it was there. The ancient Egyptians thought it lived in the heart, not the head. Aristotle believed it was tied to a kind of vital heat in the chest. Buddhist and Hindu philosophers debated it more than two thousand years ago, with some insisting that consciousness was the only real thing, and others wondering if it existed at all. Historians estimate that over 80 percent of ancient cultures tied consciousness to some spiritual force or deity.
Then came the Enlightenment, when scientists and philosophers started poking at the question like it was a weird bug in a jar. They wondered how awareness could make us invent language, compose symphonies, declare human rights, and because we are nothing if not consistent, immediately find new and improved ways to wage war. Consciousness is basically the engine behind all of human history. Without it, there would be no cities, no novels, and no late night arguments on the internet about who the best Batman is.
What We Know Today
What do we actually know now? More than we used to, far less than we want. You cannot have consciousness without a functioning brain. Destroy the brainstem and awareness is gone in 100 percent of cases1. That three pound lump of tissue between your ears is only 2 percent of your body weight, yet it hogs about 20 percent of your total energy just to keep your sense of “me” running.
Neuroscientists have identified the default mode network, the mental autopilot that hums along when you are daydreaming or reflecting on yourself. Anesthesia can drop global brain connectivity by roughly 40 percent, which lines up perfectly with your awareness fading to black2.
Modern Theories of Consciousness
The big names in modern consciousness research all have their camps, and all have their critics.
- Christof Koch has spent decades searching for the neural correlates of consciousness, the precise brain activity patterns that go with particular experiences3. Critics say his approach risks confusing correlation with causation.
- Giulio Tononi’s Integrated Information Theory tries to give consciousness a score, Phi, based on how well information is woven together in the brain4. Critics point out that you can calculate a Phi score for systems that do not seem conscious at all5.
- Stanislas Dehaene’s Global Workspace Theory treats consciousness like a mental broadcast slot. Skeptics say this might describe information sharing without addressing why it feels like anything to be you.
- Anil Seth’s controlled hallucination model says perception is a best guess shaped by past experience. While it explains illusions, proving all perception is hallucinatory risks sliding into philosophy.
- David Chalmers identified the “hard problem” of consciousness6: why neural activity produces subjective feeling. Critics argue that once we know the mechanisms, the mystery dissolves.
Near-Death Experiences (NDEs)
Then there is Dr. Bruce Greyson, who has been studying near death experiences for over 40 years7. Greyson is at the University of Virginia’s Division of Perceptual Studies8, known for researching phenomena that resist mainstream scientific models. His work centers on thousands of accounts from people who were clinically dead or nearly so, many of which share striking similarities9.
Other research hubs include:
- The Center for Consciousness Studies (University of Arizona)
- Center for Brain and Cognition (UC San Diego)
- Mind and Life Institute (Massachusetts)
- Institute of Noetic Sciences (California)
- Human Consciousness Project (global)
- NYU Langone Medical Center, where Dr. Sam Parnia has led large-scale studies of cardiac arrest survivors10
The Controversy
Roughly 10 to 20 percent of cardiac arrest survivors report an NDE11. Among these:
- ~80% describe seeing a bright light
- ~60% report profound peace
- 20–35% report a life review
Skeptics attribute this to oxygen loss, neurotransmitter surges, and chaotic memory firing. Believers counter with verified details patients sometimes describe, such as surgical instruments or room conversations during clinical death12.
Shifting and Fragile Consciousness
Consciousness is far from fixed.
- Deep meditation can change prefrontal cortex activity by up to 22%.
- Staying awake for 24 hours lowers cognition like a 0.10% blood alcohol level.
- Babies begin with a blurry version that sharpens over time.
- Brain injuries, dementia, and psychiatric conditions can warp it drastically.
Mental health impact: Depression (280+ million globally) dampens mood networks; Anxiety disorders (31% of U.S. adults) crank up threat detection; Psychosis (3 in 100 people) hijacks consciousness entirely. Traumatic brain injury affects 5.3 million Americans, yet studies show their inner lives remain rich and complex.
Consciousness vs. the Soul
Consciousness and the soul are not the same thing. Consciousness is your daily backstage pass to existence. The soul, in religious tradition, is eternal. Consciousness can be shut off with anesthesia in 95% of surgeries within 40 seconds. If the soul exists, it seems immune to propofol.
Reincarnation Research
Dr. Ian Stevenson at the University of Virginia documented 2,500+ cases of children claiming past life memories13. Famous examples include:
- James Leininger, who described details of a WWII fighter pilot’s life later confirmed historically.
- Shanti Devi, a girl in 1930s India who recalled a previous family, home, and hidden details later verified.
Skeptics argue chance, coaching, or hidden memory. Proponents say details are too specific to dismiss.
The Unresolved Mystery
A three-pound lump of gray matter produces Shakespeare, space travel, TikTok, and your 2 a.m. cold pizza craving. Some believe we’ll crack the code; others think consciousness is a fundamental property of the universe, like gravity.
And the rest of us? Just trying to drink coffee without spiraling into existential crisis, listening to that inner voice saying, “Hey, I exist,” and wondering who’s listening.
Invitation to Readers
If you have thoughts, theories, or questions about any of this, I would love to hear them. Leave a comment below and I will personally respond. If you want to dig deeper or reach out directly, visit my website at boulderpsychiatryassociates.com
FOOTNOTES
1. Crick & Koch, “The problem of consciousness,” Scientific American 267 (1992), pp. 152–159 ↩
2. Koch et al., “Neural correlates of consciousness,” Nature Reviews Neuroscience 17 (2016), pp. 307–321 ↩
3. Koch, “Neural correlates of consciousness,” Scholarpedia 1 (2004), 1740 ↩
4. Tononi & Koch, “Consciousness: Here, there but not everywhere,” Phil. Trans. R. Soc. B 370 (2014) ↩
5. Tononi, Integrated Information Theory, MIT Press (2012), pp. 147–178 ↩
6. Chalmers, “Facing up to the problem of consciousness,” Journal of Consciousness Studies 2 (1995), pp. 200–219 ↩
7. Greyson, “Near-death experience: Clinical implications,” Revista de Psiquiatría Clínica 34 (2007), pp. 116–125 ↩
8. Greyson, “The near-death experience scale,” Journal of Nervous and Mental Disease 171 (1983), pp. 369–375 ↩
9. Greyson, “Dissociation in people who have NDEs,” The Lancet 355 (2000), pp. 460–463 ↩
10. Parnia et al., “AWARE—A prospective study,” Resuscitation 85 (2014), pp. 1799–1805 ↩
11. Greyson, “Incidence and correlates of NDEs,” General Hospital Psychiatry 25 (2003), pp. 269–276 ↩
12. Lange, Greyson & Houran, “Rasch scaling validation of a core NDE,” British Journal of Psychology 95 (2004) ↩
13. Stevenson, Twenty Cases Suggestive of Reincarnation, University Press of Virginia (1966) ↩
