Consciousness – the difference between a rock and The Rock. It is a concept we struggle to define concretely despite it being something we all feel like we understand.
Imagine one day, on your state-sanctioned daily jog, you meet a humanoid robot. As you converse, it responds as a human would. When you talk about your interests, it too shares its own. When you crack a joke, it laughs. When you lob an insult about its creator, it frowns. And no, this isn’t a high-functioning engineering student.
But do the above responses make a robot truly conscious?
Many would argue that this robot is not conscious. It was simply programmed to act like a human – stimuli such as your voice and surroundings are its inputs, while its speech and actions are its outputs. It was never properly aware of its thoughts, never really had its own interests, and certainly did not feel any amount of genuine happiness or anger when talking to you.
However, there is a conflicting argument – consciousness is subjective and can only truly be felt from the inside. Even though other people are conscious, there is no way for you to experience what it is like when they think a thought or feel an emotion. You can only observe their actions and behaviour. This argument draws on the long-standing philosophical ‘problem of other minds’ , and it applies here: If all you can do is observe the behaviour of the robot from the outside, how can you be sure that it does not experience consciousness?
Such dilemmas make characterising consciousness particularly tricky, but also explain our great fascination with it and the moral and philosophical discourse it has spawned for much of human history.
Consciousness can be broadly categorised into two realms. Firstly, it encompasses the simplistic sense of being awake – that we can perceive, interact, and communicate with others and the environment.
Importantly, it also concerns having awareness – the subjective feeling of seeing an image, hearing a sound, or thinking about something . When we mention ‘consciousness’ henceforth, it is this second aspect that we refer to. A lack of this awareness is what makes artificial intelligence like the humanoid robot feel, well, artificial!
Where does consciousness come from?
Is consciousness non-physical?
Physical processes, such as contracting an arm muscle, can often be explained through cause-and-effect relationships. However, there is currently no clear cause-and-effect relationship we have identified that explains how our brains generate consciousness. We cannot even objectively describe conscious experiences, such as ‘seeing red’ or ‘feeling happy’, because unlike your arm, consciousness is not a tangible object that can be examined or explained. It is rather the lens that we examine through – it’s what allows us to feel those muscles contracting.
This predicament has led to much convoluted literature being written on the topic – digging through it makes one appreciate how far away we are from adequately identifying a physical process that explains consciousness instead.
A simpler explanation, one that pops up in many religious and philosophical schools of thought, is that there exists a non-physical mind that generates consciousness – the ‘soul’. This mind is responsible for our reason, perception and so on, while the brain is physical and thereby just a means to exercise the intentions of the mind. The figure below depicts how people are often divided on these beliefs.
Individuals’ beliefs about consciousness – The majority of subjects have the dualist view that the brain and mind are two separate entities. Most view the mind as being fundamentally non-physical, believe in the existence of a soul that is separate from the body, and that a spiritual part of us transcends life. Although ‘soul’ and ‘mind’ are sometimes used interchangeably, the soul is also thought of as an entity that can exist independently of the brain. 
Under scientific scrutiny, it feels like a cop-out to attribute consciousness to a non-physical entity just because we cannot explain it. If consciousness is non-physical, then why do substances that influence our cognition, like alcohol, alter our conscious experiences?
Although used metaphorically, misattributions of conscious thought are even engrained in language. Take the phrase: ‘follow your heart’. While it’s something I was never told as a child, the fact remains that the heart is definitely not doing any thinking and it is insulting to suggest the brain outsources one of its most elegant functions to a sack of muscle that beats every so often until you eat too much McDonalds.
Whether we are dualists or religious or whether we believe in the soul or not, the robot seems artificial because consciousness feels like it should be made of more than just matter – more than the purely physical circuits that govern the robot’s actions. Thus, it was never aware of its thoughts, never had its own interests, and certainly didn’t feel any amount of genuine happiness or anger when talking to you, or so we think…
Is consciousness physical?
The contrary argument poses that consciousness arises purely from our brain’s activity. While it resolves the above questions and makes more sense in today’s scientific world, it has some unsettling implications.
If consciousness can purely arise from matter, then what gives us the right to say the robot does not experience a form of it? After all, consciousness can still only be felt from the inside, so if we design a robot that is as complicated as our brain or is able to mimic its activity, doesn’t that make it conscious?
This material point of view has undoubtedly gained traction due to advancing neuroscientific research. We’ve even developed computing systems that attempt to mimic the electrical networks in our brains called neural networks. But exploring the biological mechanism that gives rise to consciousness presents its own challenges and questions – is the whole brain involved or is it just specific areas? Do some special ‘consciousness cells’ start firing away?
The Neurobiology of Consciousness
The brain is made up of billions of cells called neurons. Hopefully, you knew that before clicking on an article from Youth NEURO Australia. These neurons can be thought of as light bulbs wired together in very extensive and complicated circuits. During the past few decades, the development of technologies such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) has allowed us to study the brain by visualising the activity of these circuits.
By showing us exactly when and where these light bulbs are flicking on and off, fMRIs and PET scans help us see which parts of the brain are most active when an individual sees an object, thinks of something, or feels a certain emotion. Finding the neural correlates of consciousness (NCC), that is, the minimal neuronal mechanisms sufficient in producing these specific perceptions , has been the holy grail of research on the topic. This is a bit of a mouthful, so to properly understand this, let’s look at an example from one of my own experiences.
You saw your crush. You thought about asking her out. What happened next has been blacked out by your mind for it's own sanity. These three experiences are said to have a unique NCC; a unique set of neurons fired when you had each of these three specific conscious perceptions.
Not all parts of the brain are responsible for generating the sights, sounds, and sensations as we experience them. For example, injuries to the cerebellum, an area best described as the Tasmania to the brain’s mainland Australia, have little effect on consciousness and its contents. One rare case reported most cognitive function was preserved in a woman whose brain failed to develop the part entirely .
The posterior cortex is a hot zone for the NCC
Image Credit: Mesa Schumacher as cited in 
Meanwhile, the parietal, occipital and temporal regions in the posterior cortex are significantly correlated with a variety of conscious experiences, and are hence considered ‘hot zones’ for the NCC, as seen in the above image. Even when small parts are damaged or removed, it manifests in intriguing conditions like prosopagnosia – the inability to recognise faces. Conversely, these regions can be electrically stimulated during neurosurgery to creepily elicit these experiences, such as seeing faces when they are not actually present or getting the urge to move a limb .
An incomplete approach
Where our physical approach to consciousness falls short is that our studies about the neural correlates of consciousness, as its name suggests, are correlational. As any pseudoscientist won’t tell you, correlation does not equal causation and we have a long road ahead in determining why exactly these physical neural mechanisms produce experiences that seem to be so rich and subjective.
The seemingly intangible phenomenon of consciousness, including that of you – the only reader who has reached this point, thanks Mum, remains elusive. The ‘hard problem of consciousness’ still remains: Why aren’t we just like programmed robots? Why is there “something it feels like” to see the colour green?
While we cannot answer that just yet, cognitive neuroscience is rapidly advancing to bridge the gap between biology and philosophy. But reality is probably just a simulation so none of this matters anyway, right?
 Avramides A. Other Minds. In: Zalta EN, editor. The Stanford Encyclopedia of Philosophy. Summer 2019 ed: Metaphysics Research Lab, Stanford University; 2019.
 Zeman A, Coebergh JA. Chapter 31 - The nature of consciousness. In: Bernat JL, Beresford HR, editors. Handbook of Clinical Neurology. 118: Elsevier; 2013. p. 373-407.
 Koch C, Massimini M, Boly M, Tononi G. Neural correlates of consciousness: progress and problems. Nature Reviews Neuroscience. 2016;17(5):307-21.
 Koch C. What Is Consciousness?. Scientific American [Internet]. 2018 [cited 2 May 2020];318(6):60-64. Available from: https://www.scientificamerican.com/article/what-is-consciousness/