Down the rabbit hole
Indulge me for a moment, will you? I value your opinion. Your opinion, as in, one which has arisen from your mind. I would assume. It would seem unusual to consider that, perhaps, your thoughts are not your own. Stranger still to ponder the possibility that they did not arise from your mind. I digress – or maybe not. For it is this dilemma which I wish to pick your brain on.
The mind. The brain. You. Are they one and the same; entwined?
What do you think? Again, assuming it is you thinking. Assuming you feel certain enough to agree with this.
Really, with what certainty can we say anything?
You may be wondering who “I” am. I am but you, of course! I kid, but not entirely. Think of me as the brain; your brain if you wish. An excellent name I gave myself, if you ask me.
Before we spiral any deeper into this chasm that is consciousness – because that is what this is about, is that not what this, life, is all about? – I must disclose a few things.
One, I do not expect you to have answers to these questions I pose.
Because two. We do not have answers.
I apologise that I have not come bearing the answers to our existence, that I have not yet unpicked these questions of “who?”, “how?”, “why?”. I come offering an alternative. I wish to present to you these entangled threads of consciousness: of what we currently know, of what we hope to know and of where we can proceed from here.
Then it’s back to you. You get to decide what you think (again, with the thinking). Maybe, for you and the workings of your inner mind, consciousness and all it entails will be revealed in full clarity. Maybe not. You certainly won’t know unless you try.
A brief neural memoir
Many a Nobel prize has been awarded for discoveries relating to the nervous system: from the morphology of neurons (Golgi and Cajal 1906) and their electrical signalling properties (Eccles, Hodgkin and Huxley 1963), to the nature of information processing in the visual system (Hubel and Wiesel 1981) (1). Despite some obvious gaps remaining in what is known about the brain (ahem, that slight issue of consciousness), the field of neuroscience has rapidly progressed over the last century. Gone are the days of thinking I was nothing more than a cooling mechanism for the blood, as Greek philosopher Aristotle once believed (2). How dismissive of my intellect! I assure you, I have far more important things to be doing. Generating the experience of “you”, as one small matter.
The techniques developed to study the brain have also rapidly advanced. It was not until the invention of microscopes in the 19th century that the neuron doctrine even came about. Pioneered by Santiago Ramón y Cajal, this is the (now) well-accepted concept that the nervous system is made up of discrete cells known as neurons, challenging older theories which proposed a continuous neural network (3).
Today, neuroscientists have the ability to appreciate my anatomical and functional complexity at a huge range of temporal and spatial resolutions. Whole-brain connectivity can be studied using functional magnetic resonance imaging (fMRI), while the electrical activity of single neurons can be recorded using patch-clamp electrode technology. Not to mention optogenetics, chemogenetics, viral transduction: while the available experimental techniques are still unable to address all our brainy questions, the field of neuroscience has never been in a better position to get closer to answers.
The potential of neurons
Neurons: those special, excitable cells that make up the squishy entity I seem to be.
The mechanisms of how neurons detect, generate and transmit signals have been described in utmost precision. When I talk of excitable cells, I am not referring to a bunch of cheerful, eager neurons. Excitability, in this context, refers to the fact that neurons can respond to a sensory stimulus by generating and propagating electrical signals, known as action potentials.
Clearly, I am made up of slightly more than two neurons cheerfully signalling to each other back and forth. Try 86 billion, between the cortex and cerebellum combined (4). Yet, despite our deep understanding of neural signalling mechanisms, this has yet to reveal an explanation for consciousness. Individual neurons in isolation, it would appear, don’t hold the answers we want.
In turn, a focus of neuroscience research has been on the wider “neuronal correlates of consciousness”, the minimal neuronal mechanisms that are sufficient to generate a conscious experience (5). This relates broadly to the generation of consciousness itself, but also to studying the neural underpinnings of specific conscious experiences. For example, which collective neural substrates support the process of visual object recognition. This is often a focus of fMRI studies, which examine brain activity in an attempt to pin-point where in the brain a particular cognitive function may be performed.
Fancy techniques aside, some of the most fundamental insights into my regional specialisations have arisen from careful observation following selective lesions or damage to the brain. The critical, yet specific role of Broca’s area in speech production was discovered in 1861 by surgeon Paul Broca’s observations of his patient “Tan”. Tan had lost his ability to produce meaningful speech, yet was still able to comprehend speech; Broca identified a lesion in Tan’s left frontal lobe post-mortem, drawing the conclusion that this region is selectively involved in speech production (6).
But what does all of this show us?
Perhaps the only thing that neuroscientists can agree on, is that conscious experience is fundamentally, in some way, somehow, related to my activity: the brain. In turn, the activity of the brain is related to the activity of neurons; firing and signalling and transforming information.
A lot is known about neurons. Less can be said about specific cognitive functions, yet we can see correlations between the regional brain activity and particular conscious experiences.
Here lies my problem. The elephant in the room. How do we get from individual neurons to conscious experience?
A map with no destination
Enter “The Connectome” and the Human Connectome Project: a collective attempt to map the neuronal connections of the human brain, in an effort to connect structure to function (7). And in turn, for our purposes, to ideally connect this to consciousness.
The rationale is that by modelling and trying to “build” a brain using a bottom-up approach, we may therefore understand the mechanisms of how cognitive functions arise.
I’m sure it will come as no surprise that this isn’t the simplest of tasks. To measure, record and model billions of neurons and synapses requires techniques, time, and resources that are incredibly hard to come by in sufficient quantities. Excitingly, scientists have recently managed to successfully map a whole brain. That is, of a fly (8). With 3016 neurons and 548000 synapses, this was no simple feat. In case you had forgotten my own complexity, however, let me remind you of my 86 billion neurons, and estimated 1.5 x1014 total synapses in the cortex alone (4).
Progress has also been made on the human front, nonetheless. It was recently announced that a cubic millimetre of human temporal cortex has been completely reconstructed using electron microscopy, involving 1.4 petabytes of electron microscopy data (1000 Terabytes or one quadrillion bytes) (9). One cubic millimetre down, approximately a million to go.
Putting practicalities aside, let us suppose we do, one day, manage to map and model an entire human brain, in all its intricacies. What now? What does one actually do with this data, and how would this allow us to better understand how consciousness arises?
Up until now, we have been following the train of thought that consciousness, somehow, results from the activity of neurons, yet does not arise from the activity of individual neurons. This leads us to the notion that perhaps consciousness is due to the collective, computational activity of neurons working together – that with enough complexity, and enough information processing, together this will lead to the first-person experience of being “you”.
Does this actually make sense? You tell me.
Wishful thinking and conscious rocks
The notion that, at a certain level of complex neuronal signal processing, a first-person perspective of “being you” (i.e. consciousness) arises is often termed “strong emergence” or “magical emergence” (10).
With what we currently know about the properties of neurons, there is fundamentally no reason why this should happen. The “property” of consciousness, which cannot be predicted from the principles of how individual neurons function, seemingly just emerges. Consciousness, therefore, must somehow be greater than the sum of its parts, only emerging when neurons interact as a wider network.
Maybe, the answer to this is merely that we don’t understand the mechanisms of neurons as well as we think we do. It could be that we have missed a fundamental property of how neurons operate and upon discovery of this, it would suddenly be completely explicable how consciousness arises.
Or maybe, computation and neural signalling is not all there is to it.
An alternative line of thinking is that rather than consciousness being a property that “arises”, it is a basic constituent of the universe that is missing from our current model of standard physics (11). That is, consciousness has been present all along and exists in everything.
The philosophical view of ‘panpsychism’ embraces this idea to the extreme, proposing that everything within the universe is, to some degree, conscious (12). As in yes, that rock over there might just be conscious. Other theories suggest that consciousness only emerges in a recognisable form in certain conditions or at some critical threshold; myself and all my neurons apparently being one such example of the “right” conditions.
Theories of consciousness don’t just stop at computation and fundamental properties of the universe. Quantum physics, microtubule computations, electromagnetic fields; all have been proposed as part of this web of “why” (13). While some theories arguably veer more towards pseudoscience than well-founded scholarship, they all make one thing clear. At this stage, just about every idea remains fair game in the quest for answers.
Pondering hard, or hardly pondering?
The question of consciousness is far from limited to the field of neuroscience. Philosophers too have long wracked their brains in an attempt to rationalise and unpick this problem.
What unites the work of neuroscientists and philosophers alike, along with the many theories of consciousness, is that nothing provides a satisfactory explanation for why consciousness should emerge from the activity of neurons.
Philosopher David Chalmers has termed this the “hard problem”.
“Why should physical processing give rise to a rich inner life at all? It seems objectively unreasonable that it should, and yet it does” (14).
If consciousness is simply the result of high-level processing and the computational activity of neurons, why would we even need to be conscious? If all the brain is doing is computation, and thus everything can be done via computation, there would appear to be no purpose in having a subjective experience of being “you”.
Whichever side of consciousness we may be inclined to take, computational, fundamental, or otherwise, the fact remains. We cannot seem to move beyond mere description, to explanation. We have not solved the “hard problem”.
A final conundrum, and a sole certainty
Physicist Emerson M Pugh once made the somewhat sceptical remark that “if the human brain were so simple that we could understand it, we would be so simple that we couldn't.” (15)
Is the reason that we have yet to understand consciousness simply, frustratingly, that we are not meant to?
Logical conundrums aside, I rest my case. I hope I have given you some food for thought, or at the very least, not set off too dramatic an existential crisis.
Somewhere between the neural wirings of the brain and the experience of consciousness lies an answer, regardless of whether we are destined to find it out.
Make of this what you will.
And if nothing else, let me try reassuring you once again with the wisdom of René Descartes.
“Cogito, ergo sum”
“I think, therefore I am” (16).
If you are here, and you are thinking, you are conscious. You, my friend, are you.
References
Nobel Prizes in nerve signaling. Nobel Prize Outreach. September 16, 2009. Accessed October 18, 2025. https://www.nobelprize.org/prizes/themes/nobel-prizes-in-nerve-signaling-1906-2000/.
Rábano A. Aristotle’ s “mistake”: the structure and function of the brain in the treatises on biology. Neurosciences and History. 2018;6(4):138-43.
Golgi C. The neuron doctrine - theory and facts. 1906. p. 190–217. https://www.nobelprize.org/uploads/2018/06/golgi-lecture.pdf
Herculano-Houzel S. The human brain in numbers: a linearly scaled-up primate brain. Front Hum Neurosci. 2009;3:31. doi: 10.3389/neuro.09.031.2009
Koch C, Massimini M, Boly M, Tononi G. Neural correlates of consciousness: progress and problems. Nature Reviews Neuroscience. 2016;17(5):307-21.
Broca area. Encyclopedia Britannica; 2025. Accessed October 18, 2025. https://www.britannica.com/science/Broca-area
Elam JS, Glasser MF, Harms MP, Sotiropoulos SN, Andersson JLR, Burgess GC, et al. The Human Connectome Project: A retrospective. NeuroImage. 2021;244. doi: 10.1016/j.neuroimage.2021.118543
Winding M, Pedigo BD, Barnes CL, Patsolic HG, Park Y, Kazimiers T, et al. The connectome of an insect brain. Science. 2023;379(6636). doi: 10.1126/science.add9330
Shapson-Coe A, Januszewski M, Berger DR, Pope A, Wu Y, Blakely T, et al. A petavoxel fragment of human cerebral cortex reconstructed at nanoscale resolution. Science. 2024;384(6696). doi: 10.1126/science.adk4858
Chalmers D. Strong and Weak Emergence. In: Clayton P, Davies P. The Re-Emergence of Emergence: The Emergentist Hypothesis from Science to Religion. Oxford University Press; 2008.
Kitchener PD, Hales CG. What Neuroscientists Think, and Don’t Think, About Consciousness. Frontiers in Human Neuroscience. 2022;16. doi: 10.3389/fnhum.2022.767612
Goff P, William Seager, and Sean Allen-Hermanson. Panpsychism. The Stanford Encyclopedia of Philosophy. Summer 2022.
Seth AK, Bayne T. Theories of consciousness. Nature Reviews Neuroscience. 2022;23(7):439-52. doi: 10.1038/s41583-022-00587-4
Chalmers D. Facing up to the hard problem of consciousness. In: Shear J. Explaining Consciousness: The Hard Problem. MIT Press; 1997.
Pugh GE. The Biological Origin of Human Values. Routledge & Kegan Paul; 1978.
Descartes R. Principles of Philosophy. 1644.
Entwined
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