Could a conscious mind exist without a human brain? If not, then what about your robot, your pet dog, your soul and your God?

Which is really you: your mind or your brain?

That’s not an easy question to answer, because while the brain is the central processing unit of your nervous system that can be seen, touched and measured (if the skull is opened), the mind is less tangible. Yet, your mind seems incredibly real to you, being your own mental experience of life.

And while we often use the words ‘mind’ and ‘brain’ interchangeably, on digging deeper, we find that they represent different components of the same system.

Our bodies and brains are part of the objective physical world, whereas our minds and consciousness are in the subjective mental world. Confusion reigns as to the relationship between the two. Neither is reducible to the other. Yet, they are undeniably connected, as neurosurgeons are well aware.

How can the physical world of the brain and its circuits possibly be connected to a non-physical entity such as the mind? Science cannot envisage such a connection. This proposed “gap” between the physical and mental worlds, between the body and the mind, was famously identified by Rene Descartes in the 17th century. His idea bolstered the hope, widespread at the time, and still today, that the mind could somehow survive the death of the body.

Materialists would claim that there is no gap, because only the physical world exists: the mental world is just an illusion. The material brain and the body are in full control behind the scenes in every individual, as part of a deterministic world of cause and effect. Yet, many of us have a hard time accepting that our minds and consciousness are illusions.

More recently, cognitive scientists and philosophers have argued that the mind and the brain are two sides of the one coin; that the mind emerges as a higher order phenomenon from the physical processing in the circuits of the brain and body. They cite the hardware circuits and software programs in a computer as examples of linked physical and mental processes. But this analogy for the brain and the mind does not work very well. While it is true that a computer can answer mental questions through its electronic circuits, it needs to be programmed by humans to do so. It cannot, yet, initiate novel actions for which it has not been programmed or prepared — a necessary, but not sufficient, condition for the existence of consciousness.

A school of thought does hold that a future supercomputer of comparable complexity to the human brain, capable of parallel processing and learning, would possess consciousness as an emergent phenomenon. This is the ultimate endgame of AI researchers, although they are still a long way from that goal, if it is achievable at all.

Neuroscientist Michael Gazzaniga, in his 2018 book entitled “The Consciousness Instinct”, further pursues the idea that the mind and the brain are two sides of the same coin. Whither goes the mind, so goes the brain, and vise versa. There is no need to postulate a gap between them: there is no gap. They are not two but one, observed from two different perspectives; from the inside, and from the outside, respectively.

Quantum physics holds that a photon (the basic unit of light) can behave simultaneously as a particle and a wave. It only becomes one or the other through the process of observation and measurement. This is called complementarity, and holds also for the electron, the basic unit of electricity, and other sub-atomic particles.

To apply this analogy in our case, we need only to look at what happens during measurement and observation in the brain and the mind respectively. When neurosurgeons measure what is happening in the brain during mental activity, they detect only electrical pulses. Their instruments cannot capture subjective mental experiences.

On the other hand, when you or I observe what is happening inside our heads through introspection, we are unaware of any electrical pulses. We detect only subjective mental experiences, and we are able to convey them to others through language, art or music.

It is not known how the living brain might achieve this double act from a single performance. Yet, its architecture is rich with possibilities: more so than within the copper and silicon circuits of today’s computers. Witness the plethora of electrochemical processes, occurring down to the level of the single atom or molecule, within a network comprising billions of neurons and connecting synapses.

The phenomenon, whatever its origin, may have something to do with the inherent subjectivity of living things. Gazzaniga points out that life, even in primitive form, has many properties not possessed by inanimate objects. From the very beginning, life has been self-sustaining, self-initiating, self-replicating, self-evolving and self-aware (in the sense of knowing its own boundaries). Even single-celled creatures, such as bacteria, for billions of years, have had the ability to copy themselves, to copy instructions to copy themselves, and to adopt improvements in order to better survive and evolve. Today’s computers are yet to match even a single-celled creature in this regard, despite their awesome information processing and computing powers.

If the above model for the mind is valid, then it tells us something about whether we have free will; or whether, like the other physical objects in the universe, our destinies are determined by a chain of cause and effect reaching from our bodies all the way back to the Big Bang.

Yet, if in fact our minds and our brains are two sides of the one coin, then any initiative taken by our minds would be mirrored by physical processes in the neurons of our brains, as they implement our instructions. This implies that we have free will to modify our world, for better or for worse, within the limits placed on us by events beyond our control, our inherited DNA and our early environmental conditioning.

What about animals? Most dog-owners would challenge the view that dogs do not have a conscious mind of their own. Given the self-centred nature of all life, and in particular the similarities between the brains of humans and other mammals, it is probable that a continuum of gradually expanding consciousness stretches from the lower to the higher life forms.

Would it be possible then for a mind to work without a brain? For this model of the mind, no: not without some kind of physical entity that acts like a brain.

Otherwise the mind does not have a conduit through which to interact with the real world. For a mind to see it, there must be an eye. For a mind to act on it, there must be a body. For the wind to propel a ship, there must be a sail. For a TV signal to produce a moving picture, it must be pulled down from the airwaves, fed into a receiver and projected onto a screen.

For a mind to think, there must be a brain.