What is Reality?
It’s one of humanity’s oldest and most intriguing questions.
What is real? Is the world around us real or a construction of our imagination? What does it mean to be ‘real’?
These interrogations have been with us since the dawn of time and have gained importance with the advent of Artificial Intelligence, Virtual reality, and Enhanced reality.
As science and technology advance, the scientific fields have come up with ever more incredible theories of what reality truly is, such as the Quantum consciousness theory by Roger Penrose and Stuart Hameroff, or the Simulation hypothesis popularized by Nick Bostrom.
It seems we can no longer believe in our senses. What is real and what isn’t? How can we be sure?
Entertainment questioning our sense of reality is increasingly popular
According to the Oxford Dictionary, the definition of “reality” is: 1) The quality or state of being real. 2) Real existence; what is real rather than imagined or desired. 3) The aggregate of real things or existences.
However, beyond mere etymology, the answer to the question ‘What is reality?’ is not as straightforward or reassuring as we would like it to be.
Because, the more we advance in our understanding of the cosmos and the forces that shape it, the more complex that the answer gets.
Here we examine briefly the topic of reality from the perspective of philosophy, psychology, neurology, physics, and mathematics.
Philosophy
Probably no other discipline has devoted more time and effort untangling the mystery of what reality is.
From its inception in ancient Greece, philosophy has been trying to answer the question of reality, proposing different concepts which have developed in parallel to our understanding of the world.
Classical philosophy stated that reality is related to existence and the essence of the human being. In the Age of Enlightenment, Rene de Descartes’ statement, “I think, therefore I am”, became the pillar to explain consciousness, conditioning reality to direct experience.
Philosophy addresses two aspects of reality: the nature of reality itself, and the relationship between the mind (expressed in language, culture, etc.) and what we perceive as real.
Ontology (what exists by itself) and Epistemology (what we know about these things and the limits of our knowledge) are the tools used by philosophers to explain reality.
Some philosophers establish a difference between reality and existence, adding a layer of complexity to describe the world around us.
In addition, while accepting the notion that our perception of reality is shaped by external factors, most philosophers reject the notion of reality as described by physics or mathematics.
For example, in his essay “Philosophy on Mathematics and Reality”, Professor Raymond Tallis explains that “the world of physical laws -which enables predictions or quantities- is a world of quantities without qualities”, passing on to explain why a mere numeric description of reality is not accurate or complete.
Almost every philosopher has addressed the issue of reality in one way or another. Through the centuries, new theories have emerged to explain the many different concepts involved in the subjects of consciousness and reality.
However, no single approach seems to satisfy everyone, and the question of what reality is still remains open to new interpretations.
Psychology
“The concept of reality has no meaning without a point of reference (...). It is our mind that projects on things the concepts we have of them, giving meaning to the universe, creating at every moment the existence of reality in which we live.” - John Maxtell
The basis of reality in psychology is based on the concept of ‘consciousness’. We are real because we are ‘conscious’ of being real.
However, reality is also a delicate balance between our perception of the physical environment around us, and the perception of our inner self (our thoughts, memories, feelings, concepts, etc.).
Rene Magritte, “Decalcomanie”
According to psychology, human consciousness is constructed upon three layers: the conscious (our thoughts, actions and awareness of the present, which represent 10% of our consciousness), the subconscious (the actions and reactions we realize when we think, representing 50-60% of our consciousness), and the unconscious (our memories and the deep recess of our past, representing 30-40% of our consciousness).
These structures work together to construct our personal picture of what we call ‘real’.
In addition, Freudian psychology established the ‘reality principle’, which is the ability of the mind to assess the reality of the external world, and to act upon it accordingly.
We construct reality based on our senses, but also on our expectations learned through direct experience deeply ingrained in our minds. For instance, when we jump we expect to fall back to the ground, not float up indefinitely, as it would happen in dreams.
In fact, dreams and memories have an important role in our perception of reality.
Dreams, Reality and Imagination
“In sleep, fantasy takes the form of dreams. But in waking life, too, we continue to dream beneath the threshold of consciousness, especially when under the influence of repressed or other unconscious complexes.” - Carl Jung
‘Dreams are my reality’, sang Richard Sanderson in the 1980s hit song. However, the mental processes entailed in dreaming and perceiving reality are not too distant from one another.
Have you ever felt that your imagination and your dreams were truer than life itself? This is probably because both reality and imagination are processed by the same areas in the brain.
Dreams are generated by networks in the brain similar to those used to recall memories and construct scenarios when we are awake. In this process, the hippocampus combines different elements of memory into a coherent whole.
The hippocampus is involved in storing episodic and declarative memories, and studies suggest that it uses these memories to construct imagined events and scenarios.
In addition, the prefrontal cortex is less active during REM sleep -the ‘dreaming state’ sleep-, which explains why the images in our dreams often lack in logic.
Recent studies suggest that dreaming is part of a continuum of constructive thought continuously generated across waking and sleeping states.
Thanks to the significant advances in neurology in recent years, we are starting to comprehend how the brain creates ‘reality’, and how our perception of reality is linked to imagination and dreaming.
An interesting hypothesis posits that imagination and the perception of reality use the same neural pathways in the brain, but that imagination is a weaker form of perception.
Researchers think that probably the frontal cortex -the brain region in charge of planning and logical analysis- evaluates the level of intensity of these two activities by applying a ‘reality threshold’ to decides which one is ‘real’.
However, the mechanism is still unclear and requires more research.
Memories are also tightly linked to both our perception of reality and our dreams.
Much of what we do and perceive on a daily basis relies on memories stored since infancy: how to stand up, how to walk, how to move our hands, how to recognize faces and distances, etc.
For instance, we are able to watch a film and understand it because we learned from an early age how to string the different sequences and cuts into a unified continuum. The process is stored in our memories, and we access it automatically, but someone who has never watched a film before would have a hard time understanding what they see.
In a 1990 study, neuroscientists discovered that regions of the brain which were thought to be active only during sensory perception -actively seeing, listening, etc.- were also active during memory recall.
However, the brain handles and processes the information from these two activities very differently.
Moreover, the fabric of memories is fragile, and one difficult to track for veracity.
As demonstrated by researcher Elizabeth Loftus, memories can be induced through suggestion, even in people with excellent memory.
In addition, susceptible people, those with fragile mental states or suffering borderline disorders can also develop the false memory syndrome - the creation of a reality around a false memory.
Understanding how these mechanisms work in the brain may also help explain disorders such as hallucinations, aphantasia, hyperphantasia, schizophrenia, and dream-reality confusion (the inability to distinguish whether an event occurred during waking state or as part of a dream).
Salvador Dali, "The Persistence of Memory".
Neurology
“Reality is whatever your brain tells you it is” - Dr. David Eagleman
For neurologists, reality is a construction of the brain based on the interpretation of our sensorial input. The brain extracts patterns from the electrochemical signals sent by our senses, processes them, and assigns them meaning, thus creating our subjective world.
We assume that our senses are correct, even though there are subtle differences of sensitivity between individuals. For instance, my mother had a scarf in a borderline hue that she called ‘blue’, but I saw it as ‘green’, and we could never settle the argument.
Thus, the reality of each person is slightly different depending on the sensorial sensitivity of each. In addition, certain conditions such as hyperacusis (extreme hearing), synesthesia (seeing colors in numbers, letters, and sounds), or being color blind underline further these differences in perception.
In addition to our sensorial differences, our senses can be easily deceived because our brain processes sensory inputs based on expectations.
Optical illusions are a good example of this.
All lines are perfectly straight
Our senses work at unison and depend on each other to capture our perception of ‘reality’, each one providing an additional clue of the environment around us.
But while the external stimuli play a fundamental role in our perception of reality, it is the correct processing of these which produces our sense of ‘reality’.
For instance, we hear a bird sing in the garden. Our ears capture the pitch and frequency and transmit this information to our brain, which determines how loud it is and how far the bird might be. Also, in order to understand what we hear, we must access our mental sound bank and correctly determine that it is bird song, not any other sound. In addition, if we have stored knowledge about different types of bird song, we might access our memory of the type of bird that is singing.
All of these happens instantly - or so it may seem to us. But in fact, each of these perceptions run at a different speed, and it takes no less than 1/10 of a second for our brain to come up with the most appropriate “answer” to the impulses sent by our senses.
The brain is very deft at evaluating the impulses sent by our senses, cataloguing them correctly almost instantly. But the senses can be deceived rather easily, so our sense of reality is permanently shifting, rearranging, and self-correcting.
Physics
“Space-time itself and its physical properties are also a construction of the brain.” - Dr. Donald Hoffman.
Although an ever-present topic of study for centuries, the study of reality in physics has taken a phenomenal leap in the last five decades.
In the 17th and 18th centuries, classical Physics was content to enunciate reality in terms of physical reality. If we were able to determine the specific positions, volume, and velocities of a thing, we considered it ‘real’.
In the 19th century, after the apparition of the field concept and its application to electromagnetic and gravity forces, this concept expanded to include the value of the object’s field.
In the 20th century, scientists discovered that human vision is limited to a small area of the light spectrum, with the same being true about our hearing and smelling capabilities.
Scientists discovered that the world beyond our physical boundaries (as perceived and experienced by birds, insects, and non-human mammals) is rich in very different stimuli to those we are used to.
These discoveries showed that ‘reality’ was a much broader concept than the one we thought possible, but they were still not enough to shatter the conviction of reality based on physical evidence.
Human senses only perceive a fraction of the available information in the universe.
Below, a starling seen through human eyes, and seen as other starling sees it.
The comforting certainty of physical reality was finally shattered in 1927 when Werner Heisenberg formulated the uncertainty principle.
This one stated that it’s impossible to know the velocity and the position of a particle at the same time - the particle could be on point A or point B, and it’s impossible to know with certainty which one -, establishing the basis of Quantum mechanics.
According to Quantum mechanics, reality in the Universe is ambiguous, always hovering between possibilities. Things only become definite when a suitable observation forces it to settle on a specific outcome (which can’t be predicted). Based on this theory, we could say that a cat is not a cat until we decide it’s a cat.
In recent years, the Superstring theory has garnered much attention by proposing the Holy Grail of physics: the unification of the General Relativity and the Quantum Mechanics theories. However, instead of the 3 spatial dimensions and 1 time dimension we’re all used to perceive, the Superstring theory states that there would be 9 different spatial dimensions and 1 time dimension.
If this is not enough to make your jaw drop, M-Theory goes even further, positing 10 spatial dimensions and 1 time dimension, for a total of 11 different space-time dimensions.
If these theories are correct, the Universe around us would be composed of much more than we can perceive with our limited physical senses.
Perhaps Einstein was correct when he stated: “For we convinced physicists, the distinction between past, present, and future is only an illusion, however persistent.”
Orthogonal projections of hypercubes
Mathematics
“Our Universe is a grand book written in the language of mathematics” - Galileo Galilei.
Reality has long been studied and described by mathematicians since the dawn of times, but recent theories have come to revolutionize the idea of what “reality” is.
Among several other scholars and mathematicians proposing new theories on reality, M.I.T. professor Max Tegmark proposes that our universe isn’t just described by math, but that it is math.
The universe in this theory would be a giant mathematical object, part of a multiverse so huge that it would dwarf all other multiverses debated to exist.
In his book, “Our Mathematical Universe: My Quest for the Ultimate Nature of Reality”, professor Tegmark explains that we usually equate mathematics with arithmetic; but mathematics go beyond mere calculations and numbers, studying abstract structures such as geometric shapes, and patterns in nature, such as those in motion, gravity, electricity, magnetism, light, heat, radioactivity, etc.
These patterns are summarized by the laws of physics and can be described using mathematical equations.
Equations and numbers are natural hints of mathematics we find in nature. But while most physicists agree that nature can be described by mathematics, professor Tegmark proposes a bolder concept.
Based on the external reality hypothesis, which states that there is an external physical reality completely independent of humans, professor Tegmark posits that, for a description of the universe to be complete and accurate, it must be defined according to non-human concepts or constructions.
In this case, the sole possible form of coding would be mathematics since, unlike words or symbols, it is completely abstract and therefore universally understood.
The Mathematical Universe Hypothesis also states that our external physical reality is a mathematical structure. As such, we do not invent mathematical structures - we discover them and invent the notation to describe them.
Although this theory may seem unsettling, Professor Tegmark assures that accepting it demotes the notions of randomness, complexity, and change to mere illusions. This theory also implies a collection of parallel universes so vast that it would force us to relinquish our most ingrained notions of reality.
Other mathematicians who have recently explored the notion of a mathematical universe and our perceived reality include Dr. Mary Leng in her book “Mathematics and Reality”, and Frederic Patras in his study “Mathematics and Reality”.
Video: Is Reality a Mathematical Structure? (3:47")
From atomic particles and language to the concept of space-time, all the constructions we have built to measure and explain the universe around us are based on our limited human perception, since these are the paradigms that we understand.
But the universe is vast and much more complex than the human experience.
We may know the light spectrum contains waves we can’t perceive, and there are sounds we will never be able to hear. There might even be additional dimensions that we can’t perceive with our senses or even begin to imagine.
In addition, each individual can only perceive a fraction of the world around us. In order to get the full picture of reality, we need to combine a multitude of different perspectives.
Our reality is shaped by our senses, but at the same time reality is much more than what our senses can perceive.
To Learn More
*For a brief but comprehensive glance at the Simulation hypothesis popularized by Nick Bostrom, watch this illustrative video (26 min): https://www.youtube.com/watch?v=zmRTC6xhis4
*To read more about how our brains shape our reality, read the book “The Brain: The Story of You”, by Dr. David Eagleman.
*You can also watch the following episode from the PBS series “The Brain”, also with Dr. Eagleman. (56:44"): https://youtu.be/C8k-lrJrldw
Sources: “The Book of Philosophy”. Dorling-Kindersley Ltd.(2011). “The Fabric of the Cosmos”. Brian Greene. Vintage Books (2004). Quanta Magazine, Psychology Today, BBC, ScienceDirect.com, Medium.com, PhilosophyNow.org, eLifeSciences.org, Wikipedia.
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