Consciousness — The Origin of Self

28 min readSep 6, 2024

The self, the conscious mind (or the soul, from a spiritual perspective?) How did it originate? What fundamental conditions are necessary for the emergence of the ‘self’? Before diving deeper into this topic, let me share a few questions that have intrigued me since my school days:

Why is our vision specifically tuned to the visible spectrum of electromagnetic waves (and not to radio waves, X-rays, or infrared)?
Why do we have the capacity for reasoning?
Why do we have a distinct sense of identity? Why can’t we perceive or know what others are thinking?
Why do humans all have unique appearances (except for identical twins)?
Why do we possess exactly five senses, rather than three or seven?

This is a continuation of a series of blogs I originally wrote “Self, the Origin” on October 27, 2008, on Google Blogspot. This latest edition expands upon the original, incorporating more insights from philosophy, neuroscience and physics, including recent Nobel Prize-winning research in physics — what Einstein famously referred to as “spooky action at a distance.”

Before we dive into understanding vision, let’s first explore various philosophical perspectives on consciousness. These viewpoints provide diverse insights into the nature of reality and consciousness:

Monism emphasizes a single substance or reality (either physical or mental).
Dualism proposes two distinct substances (mental and physical).
Panpsychism suggests consciousness is a fundamental and universal aspect of all matter.
Idealism argues that reality is fundamentally mental or a construct of consciousness.
Materialism (Physicalism) holds that everything, including the mind, is fundamentally physical and governed by physical laws.

Monism

Monism is the view that everything that exists can be reduced to a single substance or reality.

Core Beliefs: Monists believe that reality is fundamentally one unified entity or substance. This substance can be either physical (materialistic monism) or mental (idealistic monism). Examples:

Spinoza’s Substance Monism: Baruch Spinoza proposed that there is only one substance, which he identified as “God” or “Nature,” and that everything else is a mode or expression of this single substance.
Material Monism (Physicalism): The belief that everything is fundamentally physical and that consciousness and mental states are manifestations of physical processes in the brain.
Advaita Vedanta: A non-dualistic school of Hindu philosophy that teaches that the individual soul (Atman) and the ultimate reality (Brahman) are one. Source: Stanford University

Dualism

Dualism is the belief that two distinct and irreducible substances constitute reality: the mental and the physical.

Core Beliefs: Dualists argue that the mind (consciousness, mental states) and the body (physical states, matter) are fundamentally different in nature and cannot be reduced to one another. There are two main types of dualism: substance dualism and property dualism. Examples:

Descartes’ Cartesian Dualism: René Descartes argued that the mind is a non-physical substance that interacts with the physical body through the pineal gland. This view posits a fundamental distinction between mind and matter.
Mind-Body Interaction Problem: The challenge in dualism is explaining how a non-physical mind can interact with a physical body, a problem that has led to various philosophical debates.
Dvaita Vedanta: A dualistic school of Hindu philosophy that maintains a strict distinction between the individual soul (Atman) and the supreme being (Brahman).
Abrahamic religions: Judaism, Christianity, and Islam believe in a single, omnipotent, and transcendent God who is distinct from His creation and interacts with the world. Belief in the soul’s immortality and its distinction from the body. The soul is believed to be judged by God after death. Source: Stanford University

Panpsychism

Panpsychism is the belief that consciousness is a universal and intrinsic feature of all matter.

Core Beliefs: Panpsychists argue that consciousness or a form of subjective experience is present at all levels of physical matter. They propose that even fundamental particles, like electrons or quarks, have some degree of consciousness, although not in the complex form humans experience. Examples:

Consciousness in Fundamental Particles: Panpsychism suggests that basic consciousness exists in all entities, from the smallest particles to the largest organisms, with the complexity of consciousness increasing with the complexity of the system.
Mind-Matter Continuity: This idea aligns with certain interpretations of quantum mechanics, where consciousness and observation play a role in the collapse of the wave function. Source: Stanford University

Idealism

Idealism is the belief that reality is fundamentally mental or immaterial and that the physical world is an illusion or a construction of the mind.

Core Beliefs: Idealists argue that what we perceive as physical objects do not exist independently of our perception; rather, reality is a mental construct. There are different forms of idealism, such as subjective idealism (reality depends on individual perception) and objective idealism (reality is a manifestation of a universal mind). Examples:

Berkeley’s Subjective Idealism: George Berkeley argued that physical objects only exist to the extent that they are perceived by a mind. His famous dictum “esse est percipi” means “to be is to be perceived.”
Platonic Idealism: Plato’s theory of forms suggests that non-material abstract forms (such as mathematical objects or moral truths) are the most real and fundamental aspects of reality, with the physical world being a shadow or imitation of these forms. Source: Stanford University

Materialism (Physicalism / Material Monism)

Materialism, or physicalism, is the belief that reality is fundamentally composed of physical matter, and all phenomena, including consciousness, are the result of material interactions.

Core Beliefs: Materialists assert that everything that exists can be explained by physical laws and processes. Mental states are seen as brain states, and consciousness is an emergent property of physical processes in the brain. Examples:

Neuroscience: Modern neuroscience often supports a materialist view by showing how mental states correlate with brain activity. For instance, emotions, thoughts, and perceptions can be linked to specific neural patterns or chemical processes in the brain.
Atoms and Molecules: Materialism posits that all objects and phenomena, including consciousness, are composed of and can be explained by the interactions of atoms and molecules governed by physical laws. Source: Stanford University

Personally, I lean more towards material monism, primarily because science is peer-reviewed and verifiable. I also have an affinity for Advaita philosophy, as it aligns closely with modern scientific principles — a remarkable feat considering these ideas were formulated thousands of years ago. Now that we have explored various philosophical perspectives on consciousness, let’s turn our attention to neuroscience. We’ll start by examining vision and understanding why human sight is specifically tuned to a certain range of the electromagnetic spectrum.

1. Why is our vision specifically tuned to the visible spectrum of electromagnetic waves (and not to radio waves, X-rays, or infrared)?

Vision

Many species perceive the world differently, using other parts of the electromagnetic spectrum. For instance, bats, dolphins, and whales rely on ultrasound signals (echolocation) to navigate their surroundings rather than seeing them as we do. Now, imagine if our vision were attuned to ultrasound or X-rays. Visualizing the world through these frequencies would be vastly different — seeing your friends as skeletons or perceiving objects as dark shapes through ultrasound. The image below illustrates the electromagnetic spectrum and its various wavelengths.

**Electromagnetic Spectrum —We call it as light**

According to the image above, human vision is tuned to a wavelength range between 10^-6 to 10^-7 meters, whereas TV and DVD remote controls operate in the 10^-6 to 10^-3 meter range, and some bats perceive in the ultraviolet spectrum between 10^-7 to 10^-8 meters. Meanwhile, your favourite FM radio station broadcasts at wavelengths between 10 and 10² meters. This raises the question: why is our vision specifically attuned to this particular range of the electromagnetic spectrum?

The table below outlines various categories of species — such as mammals, birds, reptiles, insects, fish, and amphibians — along with the corresponding electromagnetic spectrum range and details about their vision. Following this, we will explore the benefits of trichromatic photoreceptors and their evolutionary origins.

Source: Jacobs, G. H. (1996). “Primate photopigments and primate color vision.” Proceedings of the National Academy of Sciences. This source discusses the genetic basis and evolutionary history of color vision in primates, including the role of gene duplication and the advantages of trichromatic vision.

Trichromatic vision Advantages

Species with three types of cone photoreceptors, each sensitive to different wavelengths of light (short/blue, medium/green, and long/red), enjoy several evolutionary and ecological advantages:

Enhanced Color Discrimination:

Improved Foraging: Trichromatic vision allows mammals to distinguish between a wider range of colors, which is particularly advantageous for foraging. For example, primates can differentiate ripe fruits from unripe ones or from the surrounding foliage, enhancing their ability to select nutritious food sources.
Detection of Edible Plants: The ability to discern various shades of green, yellow, and red helps mammals identify edible leaves and plants, as well as detect toxins or plant parts that may be harmful.

Better Visual Contrast and Depth Perception:

Improved Navigation: Trichromatic vision enhances contrast sensitivity, helping mammals detect objects against varying backgrounds. This ability is crucial for navigating through complex environments like forests or dense vegetation.
Enhanced Depth Perception: Color differentiation contributes to depth perception by providing additional visual cues. This is particularly useful in three-dimensional environments, aiding in activities such as leaping between branches or avoiding obstacles.

Social Signaling and Communication:

Recognition of Conspecifics: In many primate species, trichromatic vision allows individuals to recognize subtle color variations in skin, fur, or facial coloration, which may be important for social signaling, mate selection, or identifying kin.
Emotional Cues: Color vision helps in interpreting emotional states or health status in conspecifics. For example, flushed or pale skin can indicate different emotional or physiological states.

Predator Detection and Avoidance:

Spotting Camouflaged Predators: Trichromatic vision enhances the ability to detect predators that might be camouflaged in foliage or other natural backgrounds. Subtle color differences can reveal the presence of a predator, providing an evolutionary advantage by increasing survival rates.
Detecting Motion: Color vision also aids in detecting moving objects, which can be crucial for spotting predators or prey from a distance.

Evolution of Three-Cone Photoreceptors (Trichromatic Vision)

The evolution of trichromatic vision, particularly in primates, involves several steps and genetic changes:

Gene Duplication and Mutation:

Origin of the Third Cone Type: The evolution of trichromatic vision in mammals is believed to have resulted from the duplication and subsequent mutation of the gene responsible for the medium-wavelength (green) photopigment.
Opsin Gene Duplication: About 30–40 million years ago, in the lineage leading to Old World monkeys and apes (including humans), a duplication of the opsin gene on the X chromosome occurred. This gene duplication event resulted in two separate genes: one coding for a medium-wavelength-sensitive opsin (green) and another for a long-wavelength-sensitive opsin (red).

Natural Selection:

Selective Advantage: The presence of two distinct opsin genes allowed for more precise discrimination between green and red hues. This color discrimination provided a significant survival advantage, particularly in tropical environments where distinguishing ripe fruits or young leaves from mature foliage could directly impact an individual’s ability to forage effectively.
Sex-Linked Evolution: The evolution of trichromatic vision in primates is sex-linked because the opsin genes are located on the X chromosome. In some New World monkey species, females are more likely to have trichromatic vision than males due to the X-linked nature of these genes.

Convergent Evolution:

Independent Evolution in New World Monkeys: Some New World monkeys (e.g., howler monkeys) also developed trichromatic vision independently of Old World monkeys and apes. This evolution is thought to have occurred through a similar process of opsin gene duplication and mutation, demonstrating convergent evolution where similar traits evolve independently in different lineages due to similar ecological pressures.
Polymorphic Color Vision: In many New World monkeys, trichromatic vision exists as a polymorphism, where different individuals possess different opsin gene variants, leading to variation in color vision capabilities within the population.

Source: Surridge, A. K., & Mundy, N. I. (2002). “Evolution of L and M cone opsin genes in mammals.” Molecular Biology and Evolution. This study covers the molecular evolution of the opsin genes responsible for color vision in mammals, detailing the genetic changes and evolutionary processes involved in the development of trichromatic vision.
Regan, B. C., Julliot, C., Simmen, B., Vienot, F., Charles-Dominique, P., & Mollon, J. D. (2001). “Fruits, foliage and the evolution of primate colour vision.” Philosophical Transactions of the Royal Society B: Biological Sciences. This research examines the ecological and evolutionary implications of color vision, particularly in primates, and highlights the relative advantages of trichromatic versus dichromatic vision.

Each type of vision provides unique advantages that are suited to the ecological niche and lifestyle of the species that possess it. Trichromatic vision offers several advantages over dichromatic vision or UV vision, particularly in specific environments and under certain ecological conditions.

Trichromatic vision provides significant advantages for species that rely on color discrimination for foraging (search widely for food or provisions), social signalling, and detecting predators or mates in complex, colorful environments. Let’s now explore how vision functions from a neuroscience perspective to understand how the eye processes visual information.

Occipital Lobe

The occipital lobe is the primary region of the brain responsible for processing visual information. It is located at the back of the brain and is the smallest of the four major lobes of the cerebral cortex. The occipital lobe plays a crucial role in interpreting the information received from the eyes, allowing us to understand and interact with the visual world.

Key Functions of Occipital Lobe

Spatial Processing (V1, V2, V3): Spatial processing refers to the brain’s ability to interpret and understand the spatial relationships between objects and navigate through and interact with the environment.
Color Processing (V4): Color processing is the ability of the brain to interpret the wavelengths of light reflected from objects, allowing for the perception of different colors.
Distance and Depth Processing (V1, V2, V3): Distance and depth processing refers to the brain’s ability to perceive the relative distance of objects from the viewer and the three-dimensional structure of the environment.
Object and Face Recognition (V4, V5, MT): Object and face recognition involves identifying and categorising objects and faces based on their shapes, patterns, and other visual features.
Information Sharing: Information sharing refers to communicating and integrating visual information processed in the occipital lobe with other brain regions (hippocampus, amygdala, etc) to create a unified perception of the environment and support various cognitive functions.

The Visual Processing Pathway in the Occipital Lobe

Visual processing in the occipital lobe follows a hierarchical pathway:

1. Input from the Eyes to the Occipital Lobe:

Light enters the eyes and is focused on the retina, where photoreceptor cells (rods and cones) convert light into electrical signals. These signals are processed by retinal neurons and transmitted via the optic nerve to the lateral geniculate nucleus (LGN) in the thalamus.
The LGN acts as a relay center, sending the visual information to the primary visual cortex (V1) in the occipital lobe.

2. Initial Processing in V1:

V1 performs the initial analysis of visual input, detecting fundamental features like edges, orientation, motion, and contrast.
Neurons in V1 are highly specialized, responding to specific aspects of the visual stimulus, such as a particular angle of a line or a specific direction of motion.

3. Intermediate Processing in V2:

V2 receives inputs from V1 and continues processing by integrating these features to form more complex visual representations.
V2 is involved in interpreting depth and stereoscopic vision, helping to reconstruct the 3D structure of the visual environment from the 2D retinal images.

4. Advanced Processing in Higher-Order Visual Areas:

V3 processes dynamic forms and contributes to motion perception.
V4 focuses on color processing and the perception of complex shapes. It helps in recognizing objects based on their color and form.
V5/MT is essential for detecting motion and understanding the spatial relationship of moving objects

Source: Kandel, E. R., Schwartz, J. H., & Jessell, T. M. (2013). “Principles of Neural Science”. A comprehensive neuroscience textbook detailing the structure and function of the visual system, including the occipital lobe and its role in visual processing.

The occipital lobe is the central hub for visual processing in the brain, starting from the initial reception of visual information in the primary visual cortex (V1) to more complex interpretations in higher-order visual areas (V2, V3, V4, V5/MT). Its role is to analyze and interpret the various aspects of visual stimuli, enabling the brain to construct a coherent and dynamic visual representation of the environment. This processing is fundamental for various cognitive functions, including recognition, navigation, decision-making, and social interaction.

The occipital lobe interacts with other regions of the brain involved in episodic memory (hippocampus), emotion (amygdala), and decision-making (prefrontal cortex) to provide a comprehensive interpretation of the visual environment, integrating it with past experiences, and emotional states, and planned actions.

Let’s now examine an illusion to gain insights into visual perception and understand how the brain processes information.

Lilac Chaser illusion

The Lilac Chaser illusion, also known as the Pac-Man Illusion, is a type of optical illusion that demonstrates several phenomena related to visual perception, including negative afterimages, color perception, and apparent motion. This illusion was first described by Jeremy Hinton in 2005 and is widely used to illustrate how our visual system processes and interprets color and movement.

Stare at the center cross for at least 30 seconds to experience the three phenomena of the illusion

The Lilac Chaser illusion works through a combination of visual phenomena that create the perception of colors and movement that aren’t actually there:

1. Negative Afterimage:

When you stare at a particular color for a prolonged period, the cone cells in the retina responsible for detecting that color become “tired” or less responsive, leading to a negative afterimage. For example, staring at a lilac dot causes the cones sensitive to lilac light to adapt or fatigue. When the dot is removed or the viewer shifts focus, they see the complementary color (green in this case) where the lilac dot was.
In the Lilac Chaser illusion, as the viewer fixates on the central point, the lilac dots around the circle appear to fade or disappear. The space where each lilac dot appears to turn green due to the negative afterimage effect.

2. Troxler Fading:

Troxler fading is a phenomenon where stationary objects in the peripheral vision fade or disappear when one fixates on a central point for a while. The brain deprioritizes the static or unchanging visual information outside the central field of focus. In the Lilac Chaser illusion, as the viewer focuses on the central point, the lilac dots around the circle gradually fade from perception due to this fading effect.

3. Apparent Motion:

The illusion of a moving green dot (where the lilac dot disappears) is also due to apparent motion, a phenomenon where the visual system perceives motion between static images shown in quick succession. As the lilac dots disappear and the negative afterimage appears in quick succession around the circle, the brain perceives a green dot moving around the circle.
This perceived motion is an example of the “phi phenomenon,” where the brain fills in gaps in the motion between the afterimages, creating the illusion of continuous movement.

4. Color Perception:

The illusion plays on color perception mechanisms in the brain. As viewers stare at the central fixation point, their perception of the lilac color adapts, and they begin to see a complementary color (green) when a lilac dot appears to disappear. This effect is intensified by the contrast between the neutral gray background and the lilac dots. Source: New World Encyclopedia — Lilac Chaser

The Lilac Chaser illusion is a fascinating example of how the brain processes visual information, combining elements of color perception, afterimages, peripheral vision, and motion perception. It effectively demonstrates the complexity of the visual system and how it integrates different types of information to create a coherent perceptual experience, even when that experience does not correspond to reality.

This provides a thorough overview of how vision functions from a neuroscience perspective and addresses our initial question: Why is our vision specifically tuned to the visible spectrum of electromagnetic waves (and not to radio waves, X-rays, or infrared)? We have explored the ecological advantages this provides to species living in a vibrant, colorful environment.

Let’s now turn our attention to the next question: Why do humans possess the capacity for reasoning? We will begin with a philosophical exploration of reasoning, examining the evolution of rational thought in human history and how it laid the foundation for modern science.

2. Why do we have the capacity for reasoning?

Rationalism and Empiricism are two major philosophical schools of thought that debate the origins and nature of human knowledge. Both offer distinct theories regarding how we come to know the world, how knowledge is justified, and what constitutes truth.

Rationalism

Philosophers like René Descartes and Baruch Spinoza emphasized the role of reason as the primary source of knowledge and truth. They argued that rational thought allows individuals to arrive at certain truths that are independent of sensory experience. Rationalism suggests that the capacity for logical reasoning is inherent in the human mind. Descartes is often considered the father of modern philosophy and a key proponent of rationalism.

Descartes famously stated, “Cogito, ergo sum” (“I think, therefore I am”), implying that the act of thinking is the most indisputable proof of existence. Although I consider myself a rationalist, I do not fully subscribe to the concept of “Cogito Ergo Sum.” I will elaborate on my viewpoint in the next part of this series, where we will explore the third question: the origin of the “self.”

Descartes argued that certain ideas are innate and not derived from sensory experience. For instance, the concept of God, mathematical truths, and logical principles are embedded in the human mind. He believed that through systematic doubt and methodical reasoning, we can achieve certainty about these innate ideas.

Descartes employed a method of radical doubt, systematically doubting everything that could be doubted until he arrived at something that could not be questioned — the existence of the thinking self. He concluded that reason, rather than experience, is the primary source of knowledge.

Baruch Spinoza, another key rationalist, believed in the unity of substance and that all things are aspects of a single, infinite substance he identified as “God” or “Nature.”

Spinoza employed a geometric method of reasoning similar to mathematics, aiming to demonstrate philosophical truths with the certainty of a geometric proof. He argued that human beings could achieve knowledge of the world through reason alone.

Spinoza distinguished between different kinds of knowledge: opinion or imagination (based on sensory experience), reason (based on logical deduction), and intuitive knowledge (the highest form, providing direct insight into the nature of reality).

Like Descartes, Spinoza dismissed the reliability of sensory experience, which he saw as misleading and incomplete, arguing instead for a rational understanding of the world as a unified whole.

Empiricism

In contrast, empiricists like John Locke and David Hume argued that knowledge and rational thought are derived from sensory experience. They believed that the mind begins as a blank slate and that rational thinking develops through the accumulation of experiences and observations.

John Locke is often considered the founder of modern empiricism. He argued that the mind at birth is a “blank slate” and that all knowledge is acquired through experience, particularly sensory experience.

Locke rejected the rationalist notion of innate ideas, contending that all knowledge derives from sensory experiences and reflection upon those experiences. He argued that if certain ideas were truly innate, they would be universally recognized and understood by all humans, which is not the case.

Locke distinguished between simple ideas (derived directly from sensory experience) and complex ideas (constructed by the mind through combining simple ideas). He emphasized the importance of experience as the foundation for all knowledge. Locke advocated for a scientific approach to understanding the world, relying on observation, experimentation, and reflection.

David Hume is known for his rigorous empiricism and scepticism. He took Locke’s ideas further, arguing that all human knowledge comes from sensory experience, and he was deeply sceptical about the possibility of certain knowledge.

Hume differentiated between impressions (vivid, immediate sensory experiences) and ideas (fainter images of these impressions in thinking and reasoning). He argued that all ideas are ultimately derived from impressions.

Science Combines Rationalism and Empiricism

Immanuel Kant’s “Critique of Pure Reason” (1781) is one of the most influential works in Western philosophy. In this groundbreaking work, Kant sought to address the central debates between the two major schools of thought in the 17th and 18th centuries: Rationalism and Empiricism. His goal was to reconcile these opposing viewpoints and establish a new foundation for understanding human knowledge, experience, and metaphysics.

**Immanuel Kant: 1724–04–22 to 1804–02–12**

Kant aimed to combine the strengths of both Rationalism (represented by philosophers like René Descartes and Baruch Spinoza) and Empiricism (represented by philosophers like John Locke and David Hume) while addressing their limitations. Rationalists argued that knowledge could be derived from reason alone, using innate ideas and deductive logic. Empiricists, on the other hand, contended that all knowledge comes from sensory experience.

Kant proposed a “Copernican Revolution” in philosophy: instead of assuming that knowledge must conform to the objects of experience (as both rationalists and empiricists had done), Kant suggested that objects of experience conform to the structures of human cognition.

Today, science utilizes both rationalist and empiricist approaches to uncover the nature of reality through reliable (mathematical) theories and verified using empirical data.

A prime example of rationalism is Einstein’s General Theory of Relativity, (published in 1915) which (mathematical equations) predicted the curvature of spacetime. This theoretical prediction was later empirically validated when the bending of light from a star was observed during a solar eclipse (in 1919) — a classic example of empiricism at work.

**Albert Einstein** **— Special Theory of Relativity (1905) and General Theory of Relativity (1915)**

Einstein posed the challenge this way: During a solar eclipse, map the positions of stars near the sun while the moon completely blocks the sun’s light, making the background stars visible. Then, these observations will be compared with the positions of the same stars when there is no eclipse. If his theory of general relativity was accurate, there would be a slight shift in the stars’ positions — a subtle change undetectable to the naked eye but measurable with precise instruments.

In 1919, English astronomers Arthur Eddington and Frank Dyson led separate expeditions to test Einstein’s theory — Eddington to the island of Principe off the west coast of Africa, and Dyson to Sobral, Brazil. The pivotal day was May 29. When their findings were revealed to the world, it fundamentally changed our understanding of the universe.

**Eddington and Dyson proved Einstein’s General Theory of Relativity in 1919**

Einstein’s General Theory of Relativity serves as a prime example of rationalism and deductive reasoning, grounded entirely in mathematics. His equations made several predictions, including the curvature of space. However, validating the theory’s accuracy required empirical evidence, which astronomers Eddington and Dyson obtained independently through their experiments. This exemplifies why physics is often regarded as the “mother of all sciences”: its foundations are mathematical, and its equations yield predictions that can be empirically tested and verified by other scientists, aligning with Immanuel Kant’s philosophy of integrating rationalism and empiricism.

The discovery of the Higgs Boson offers an even more elegant and sophisticated illustration. The scientists who formulated the equations predicting the Higgs Boson had to wait 50 years for empirical data to confirm their hypothesis.

Peter Higgs, along with other physicists such as François Englert, Robert Brout, Gerald Guralnik, C.R. Hagen, and Tom Kibble, predicted the existence of the Higgs boson in 1964. This prediction was part of the effort to explain how elementary particles acquire mass. The concept arose within the framework of the Standard Model of particle physics, specifically as a solution to the problem of spontaneous symmetry breaking in gauge theories.

**Peter Higgs predicted the existence of the “God Particle” — the particle responsible for giving mass to other particles.**

The Large Hadron Collider (LHC) took approximately 10 years to build, from 1998 to 2008. It was constructed at CERN (the European Organization for Nuclear Research) near Geneva, Switzerland, and is the world’s largest and most powerful particle collider (as of 2024).

The cost of building the LHC was approximately €4.6 billion (around $5.5 billion USD) at the time of its construction. Around 10,000 scientists, engineers, and support staff from over 100 countries were involved in the LHC project. This workforce came from various scientific institutions worldwide, collaborating on both the design, construction, and operation of the collider, as well as the analysis of the experimental data.

The search for the Higgs boson officially began when the LHC was operational in 2008. The experiments primarily conducted by two large detectors, ATLAS and CMS, took about four years to accumulate enough data to make a discovery. On July 4, 2012, CERN announced the discovery of a new particle consistent with the Higgs boson, a monumental achievement that confirmed the predictions made almost 50 years earlier.

Peter Higgs and François Englert were awarded the Nobel Prize in Physics in 2013.

I took the time to discuss various philosophical schools of thought to highlight the importance of reasoning, a skill that we, as a species, have honed over centuries.

Now, let’s examine this from a neuroscience perspective, exploring how reasoning functions and its evolutionary background.

Capacity to Reason — from a Neuroscience Perspective

The origin of rational thoughts is a complex interplay of biological, evolutionary, and cognitive factors. Rational thinking involves the ability to reason, make decisions, solve problems, and think logically, which are hallmarks of higher cognitive functioning. The development of rational thought has roots in both the brain’s structure and function and the evolutionary pressures that shaped human cognition.

**Capacity to Reason — Key Brain Components**

Prefrontal Cortex (PFC)

The prefrontal cortex is the region of the brain most associated with rational thinking and higher-order cognitive functions. It is located at the front of the frontal lobes and involves planning, decision-making, social behavior, and moderating behavior based on future consequences. The PFC is highly developed in humans compared to other species, which is crucial for our capacity for rational thought.

Anterior Cingulate Cortex (ACC)

The ACC plays a role in conflict monitoring and error detection. It helps the brain detect when there is a conflict between different thoughts or actions and initiates cognitive control to resolve the conflict. This function is essential for rational thinking, as it allows for error correction and adaptive behavior.

Hippocampus and Medial Temporal Lobes:

These regions are important for memory formation and retrieval, which are critical for rational thought. Rational thinking often involves drawing on past experiences and learned information to make decisions and solve problems

Episodic memory is a type of long-term memory that involves the recollection of specific events, situations, and experiences. It allows individuals to remember personal experiences and events, often with a detailed awareness of the time, place, emotions, and other contextual information surrounding those events. Episodic memory is contrasted with semantic memory, which involves general knowledge and facts that are not tied to personal experiences. The following neural components are engaged in different stages — encoding, consolidation, retrieval, and reconsolidation — of episodic memory.

Medial Temporal Lobe
Hippocampus
Prefrontal Cortex
Posterior Parietal Cortex
Anterior and Posterior Cingulate Cortex
Amygdala

Parietal Lobes

The parietal lobes, particularly the inferior parietal lobule (Supramarginal Gyrus & Angular Gyrus), are involved in Language, Mathematics, Numerical reasoning and Spatial awareness, which are components of rational thought processes.

Presence of Angular Gyrus in Different Species

The angular gyrus, as a distinct anatomical and functional region, is primarily a feature of the human brain and is less distinctly present in non-human species. However, analogous regions involved in similar cognitive processes exist in other species, particularly among primates.

1. Humans:

The angular gyrus is well-defined and highly specialized in humans, playing a crucial role in language, mathematics, spatial cognition, and self-awareness.

2. Non-Human Primates (Great Apes, Monkeys):

Great Apes (e.g., Chimpanzees, Gorillas, Orangutans): While the angular gyrus is not as distinctly defined as in humans, regions of the inferior parietal lobule in great apes show some specialization for spatial cognition, tool use, and social behavior. These areas can be considered homologous to the human angular gyrus, supporting functions such as understanding complex social dynamics and manipulating objects.
Monkeys (e.g., Macaques): In monkeys, the homologous region to the angular gyrus is less developed but still participates in multimodal integration and some spatial processing. However, the cognitive functions supported by this region in monkeys are more limited compared to great apes and humans.

3. Other Mammals:

In most other mammals, a distinct angular gyrus or its equivalent is not clearly defined. The evolutionary development of the angular gyrus seems to be closely tied to the emergence of complex cognitive functions, such as language and advanced social cognition, which are more pronounced in primates.
Some degree of multimodal integration occurs in the parietal cortex of other mammals, but these regions do not exhibit the same level of specialization or development seen in primates.

4. Birds and Reptiles:

Birds and reptiles do not have an angular gyrus per se. Their brains are structured differently, with different regions performing analogous functions. For example, in birds, the nidopallium caudolaterale is involved in complex cognitive functions similar to those performed by the human angular gyrus, such as problem-solving and tool use in corvids (e.g., crows, ravens).
In reptiles, the brain regions associated with higher-order processing are more limited, reflecting their less complex social structures and cognitive demands.

Source: Geschwind, N. (1965). “Disconnexion syndromes in animals and man.” Brain. Discusses the role of the angular gyrus in language and cognitive functions, including its evolutionary aspects.

The angular gyrus has evolved primarily in primates, with significant expansion and specialization in humans. This region supports complex cognitive functions, such as language processing, mathematical reasoning, spatial cognition, and social cognition.

While non-human primates have regions in their parietal lobes that function similarly to the human angular gyrus, these regions are less developed and specialized. Other mammals, birds, and reptiles do not have a distinct angular gyrus, although some have evolved different brain regions to support analogous functions.

Adaptive Advantages of Rational Thought

Problem Solving and Tool Use: The evolution of rational thought is closely tied to the development of advanced problem-solving abilities. Early humans and their ancestors needed to solve complex problems to survive, such as finding food, creating tools, building shelters, and navigating social hierarchies. The ability to think rationally and devise strategies for these tasks provided a significant survival advantage.
Social Cooperation and Communication: Rational thought is also linked to the evolution of social behaviors and cooperation. Humans are highly social animals, and effective social interaction requires understanding others’ intentions, making decisions that benefit the group, and negotiating social dynamics. These activities require advanced cognitive functions, including theory of mind (understanding others’ perspectives), strategic thinking, and ethical reasoning.
Language and Abstract Thinking: The development of language is another key factor in the evolution of rational thought. Language allows for abstract thinking and the communication of complex ideas, which are fundamental to rational reasoning. The ability to discuss hypothetical scenarios, plan for the future, and share knowledge across generations has significantly enhanced humans’ capacity for rational thought.
Cultural Evolution and Learning: Rational thought has also been shaped by cultural evolution. The transmission of knowledge, skills, and values through social learning and cultural practices has reinforced the development of rational thinking. Human societies have developed formal systems of education, scientific inquiry, and philosophical reasoning that build upon and refine innate cognitive abilities.

Evolutionary Time Scale — Prefrontal Cortex, Trichromatic Vision & Angular Gyrus

The prefrontal cortex, as part of the frontal lobe, began to evolve in early mammals over 200 million years ago during the Mesozoic era. The development of the frontal cortex in early mammals was associated with enhanced olfactory functions (sensory processes) and more complex behavioral responses, allowing for better environmental navigation and predator-prey dynamics.
65 to 55 million years ago: Expansion of the prefrontal cortex in early primates, driven by the need for enhanced motor coordination, sensory integration, and spatial navigation in complex arboreal environments.
40 to 30 million years ago: Further development and specialization of the prefrontal cortex in anthropoid primates, associated with more complex social behaviors, foraging strategies, and cognitive abilities. At the same time, Trichromatic vision also evolved in primates.
Last 10 million years: Significant specialization of the prefrontal cortex in great apes and humans, supporting advanced cognitive functions, social cognition, and abstract reasoning.
Last 2 to 3 million years: There has been significant expansion and increased specialization of the prefrontal cortex in humans, fostering unique cognitive abilities such as advanced language, symbolic thinking, and moral reasoning. The Angular Gyrus emerged in the Homo lineage around this same period, contributing to the evolution of Homo sapiens as a superior species.

The origin of rational thoughts is rooted in a combination of biological evolution, neurological development, cognitive processes, and cultural influences. The development of the human brain, particularly the prefrontal cortex, provides the structural basis for rational thinking. Evolutionary pressures, such as the need for problem-solving, social cooperation, and cultural learning, have shaped our capacity for rational thought.

Philosophical and psychological perspectives offer insights into how rational thought develops and operates, integrating both innate cognitive abilities and experiential learning. Emotions are crucial in shaping decision-making and reasoning, often in intricate and multifaceted ways. Let’s now summarize what we’ve covered so far and revisit the questions that guided our exploration.

We began this discussion with the following two key questions:

Why is human vision specifically attuned to the visible spectrum of electromagnetic waves, rather than to radio waves, X-rays, or infrared?
Why do humans possess the capacity for reasoning?

Regarding the first question, we explored the benefits of Trichromatic vision (light, the visible spectrum of electromagnetic waves, Originated in primates 30–40 million years ago) and how it aids in foraging, social signalling, and predator detection.
As for the second question, The prefrontal cortex, as part of the frontal lobe, provides the structural basis for rational thinking, began to evolve in early mammals over 200 million years ago and the significant evolutionary expansion of the Angular Gyrus/IPL(a 6–7 fold increase, Originated in Homo Lineage around 2–3 million years ago), which propelled Homo sapiens into a superior species. This evolutionary development supports complex cognitive functions, such as language processing, mathematical reasoning, spatial awareness, and social cognition.

These insights lead us to our next question: the Origin of the Self. We will delve into this topic in the next part.