Consciousness is a term that is quite intuitive to every human being, yet if you are to ask anyone to provide you with a definition, you would receive a broad and fuzzy description. The Oxford Languages dictionary defines consciousness as “The fact of awareness by the mind of itself and the world”. However, this simplification does not do justice to the large collection of literature that has been built on the subject.

Many schools of thought have provided a variety of competing ideas that aim to better understand what it is that gives rise to the process through which we experience our surroundings and our mind’s inner mechanisms. The most unsettling part is not that we can’t seem to discover the precise answers to our sentience, it is the fact that we don’t even know what are the questions we should be asking.

What is consciousness? Why is it, evolutionarily speaking, beneficial for consciousness to develop? Where is the line between a conscious system and a non-conscious one? Is it even possible to objectively determine whether anything is conscious?

To begin answering these questions, we should first note that the term ‘consciousness’ gets thrown around under multiple distinct meanings. The Standford Encyclopedia defines two general ideas: Creature consciousness and State consciousness. The former has to do with the level of awareness we associate to an external creature, while the latter is the notion we use to describe the mental state that a being is currently in. The Standford page goes into much deeper detail that I can possibly explore in this post, and I recommend you give it a read if your want a nice introduction into this field of philosophy.

Creature consciousness and the issue with definitions

Lets say we define consciousness as awareness of one’s environment and it’s internal states. Perhaps a simpler way to explore consciousness is by trying to compare the levels of consciousness of different entities. On the one side, everyone would agree that a simple stone is not at all conscious. However, what about a mouse? Ok, maybe a mouse is conscious enough to deserve the term, but what about a spider? Spiders are capable of navigating their surroundings, as well as being aware of their inner biological needs. So maybe we can squeeze spiders under the ‘consciousness’ umbrella? What about single-celled organisms? What I’m getting at here is that maybe this form consciousness can be seen as a spectrum with inanimate objects on one side and complex intelligent beings on the other. Maybe over many small incremental steps, evolution has climbed this scale from inanimate unicellular processes, to somewhat-conscious simple multicellular organisms, to the complex intelligent apes we are today.

The youtube channel In a Nutshell has a very nice video on this very idea. The first step towards consciousness is possibly a unicelullar being capable of reacting to the level of food in its environment. Reacting to inner states such as the level of hunger can yields advantages in the evolutionary process. Furthermore, being aware of your surroundings, as well as building an inner representation of the world around you allows for navigating towards food sources. Soon after, we start having complex creatures with ever-more developed cognitive functions that will eventually resemble organisms that we more traditionally refer to as ‘conscious’.

But this definition is not without its controversy. Some have argued that under this definition a simple transistor would meet the most basic interpretation of consciousness, since the transistor is aware of its inner state and reacts to the environment according to this inner state. We, of course, don’t go around treating transistors as if they were conscious beings, but it makes you wonder what other systems fit this definition of consciousness. Another example of a type of edge case to this definition are superorganisms such as bee colonies. One can argue that a bee colony meets the criteria for consciousness. The colony is aware of its biological needs and desires, and reacts accordingly given its surroundings. On the other hand, human society behaves in a similar way, but we wouldn’t go around referring to our cities as conscious beings.

This brings me to another issue with consciousness: We have trouble pinpointing where consciousness is localized. You yourself, a conscious creature, are here thanks to the thing you call a brain. However, the brain is just a collection of neurons, which we wouldn’t refer to as individual conscious entities. So where do YOU exist? Are you the network of neurons that make up your brain? Are you the electrical pattern continuously firing in your brain? Perhaps both? Unfortunately there is no easy answer to these questions, and every attempt to search deeper into this issue only brings forth further questions.

Say, for instance, that we consider the cognitive processes that go on in someone’s mind to be correlated with some measure of being conscious. Is it correct to say that consciousness is located in the brain? And if so, which regions of the brain are necessary for consciousness? The information processing necessary for plenty of motor responses that we exhibit don’t necessarily take place in the brain at all. Whenever you accidentally burn yourself, the information perceived at your limbs travels to the spinal cord, where an action is automatically taken before the signal is even able to reach your brain. These kinds of evidence seem to imply that the collection of matter that gives rise to consciousness has very fuzzy borders. This issue, however, have even weirder implications.

Take a person, let’s call him Adam, who had a serious brain injury that lead to him having anterograde amnesia and thus losing the ability to create new memories. He carries around a notebook where he writes down all important information he wants to recall later in the day, and for all intents and purposes, he is able to lead a normal day-to-day life. Lets take another person, Bob, who has never suffered from such an injury and is able to recall memories normally using his brain. We could argue that Adam’s notebook is equivalent to the part of Bob’s brain responsible for storing memories. Is this notebook part of the conscious entity that makes up Adam? At the end of the day, part of the internal state of Adam lives in the notebook.

If you think the previous example is some far-fetched edge case, think again. In philosophy, the idea of enactivism claims that cognition is not exclusively tied to the workings of an ‘inner mind’, and that a mind, if able to, will prefer to push cognitive processes outside of the brain. This is exactly what we see happen in daily lives when we, for example, push simple mathematical operations onto our calculators. The same could be said about hiring a secretary, part of your cognition could be said to live within your secretary. Now, one could argue that these examples are not permanently part of someone’s cognitive workspace, and so calling it part of that person’s consciousness is not fair. However, I want you to think about the ever-increasing level of reliance we have on our smartphones. They are becoming ever-present in our lives. Our smartphones are already learning about our needs and desires, about the way we think and behave… how long until they become an indistinguishable part of our minds?

State consciousness and the subjective experience

The other concept that people refer to with the word ‘consciousness’ is the subjective experience that a conscious being possesses. This kind of consciousness is a lot more problematic to define, and there is no consensus among schools of philosophy on the nature of this experience.

There are a lot of different theories regarding the nature of state consciousness. Dualism is one such doctrine. Dualism says the mental and the physical are two separate entities. In some sense the experience of being conscious happens in another plane of existence and it is not subject to the laws of nature. This idea has obviously been highly criticized for a variety of reasons.

First, there is no way to know what is meant by such alternate plane or that it even exists altogether. Another problem is best expressed through the analogy of ‘The Ship of Theseus’. Take a brand new wooden ship which, slowly over the years, has more and more of its wooden parts being replaced. If all pieces of the original ship are eventually replaced, is it still the same ship? Does your consciousness stay the same over time?

This leads to a whole other range of questions. What defines your subjective experience? If dualism says that the mental is separate from the material, can a subjective experience exist irrespective of the current material? A very interesting research project is that of OpenWorm. The idea goes as follows: Take a roundworm and map all of its neurons and muscles. Next, simulate all of those connections. Results show that the simulated worm behaves the same as a real roundworm. However, this begs the question, does the simulated worm experience the same subjective mental state as the real worm when it was mapped? Can the same consciousness exist across different materials?

Another branch of philosophy that looks into state consciousness is the doctrine of materialism: “the world is entirely physical”. Modern neuroscience tends to fall under this doctrine since its philosophy revolves around the mind emerging from the brain. It is really hard to be a dualist given the overwhelming evidence showing that changes in the brain lead to changes in awareness being reported by the participant (stimulation, drugs, injuries, …). However, this gets us no closer to understanding what consciousness is. After all, we can’t directly observe someone’s first-person experience of the world by looking at their brain, we have to take their word for it. On the other hand, one can’t simply claim there is no such thing as a subjective experience, as that would be hypocritical. It is undeniable that YOU yourself experience such subjective state.

There is a famous thought experiment going by the name of “The philosophical zombie” that aims to show that it is in fact impossible to prove that state consciousness exists on anyone except for yourself. It could very well be the case that everyone around you are simply ‘empty shells’. They might exhibit complex behaviour, but at the end of the day they are zombies acting according to some predetermined inner rules. You obviously know that YOU yourself experience consciousness, but no form of interaction with anyone else will ever provide definitive proof of whether they posses a subjective experience.