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Consciousness: the story on HearLore | HearLore
Consciousness
In 1643, the English poet John Milton used the word conscious to describe not a human mind, but a grove of trees, marking the first recorded instance of the term applied to inanimate objects. This linguistic shift from describing shared human knowledge to describing an internal state began centuries before the modern scientific study of the brain. The word conscious derives from the Latin conscius, meaning to know together, originally referring to a secret shared between two people. By the 17th century, philosophers like Thomas Hobbes were using the term to describe when two or more men know the same fact, yet the concept of an inner life known only to the self was still taking shape. The first philosopher to use the Latin word conscientia in a way resembling modern consciousness was René Descartes, who wrote of internal testimony in 1651. Descartes proposed that consciousness resided in an immaterial realm called res cogitans, distinct from the physical world of res extensa. He suggested that the interaction between these two realms occurred within the pineal gland, a small structure in the brain that he believed was the seat of the soul. This dualist view, which separated mind from body, dominated philosophical thought for centuries, yet no alternative solution has ever gained general acceptance. The mystery of how a physical brain produces a subjective experience remains the central problem of consciousness studies today.
The Stream Of Experience
William James, writing in 1890, described consciousness not as a static object but as a stream, a continuous flow of thoughts and sensations that cannot be divided into discrete parts. Before James, philosophers treated the mind as a collection of separate elements, but James argued that the mind was a process of constant change. He noted that the word content had been recently invented to replace the word object, suggesting that the mind was not a container holding things, but a dynamic activity. James introduced the concept of the stream of consciousness, which included continuity, fringes, and transitions, to explain how we experience the world. This view contrasted sharply with earlier theories that viewed consciousness as a series of isolated mental states. James also recognized the difficulty of describing psychological phenomena, acknowledging that commonly used terminology was a necessary starting point for more precise scientific language. His work laid the foundation for modern psychology, influencing how we understand the relationship between the inner world of thought and the outer world of perception. The stream metaphor remains a powerful tool for understanding the fluid nature of human experience, even as neuroscientists seek to map the specific neural correlates of consciousness.
The Hard Problem Of Being
Common questions
When did John Milton first use the word conscious to describe inanimate objects?
In 1643, the English poet John Milton used the word conscious to describe a grove of trees, marking the first recorded instance of the term applied to inanimate objects.
Who was the first philosopher to use the Latin word conscientia in a way resembling modern consciousness?
René Descartes was the first philosopher to use the Latin word conscientia in a way resembling modern consciousness when he wrote of internal testimony in 1651.
What year did Thomas Nagel publish the paper What Is It Like To Be A Bat?
In 1974, the philosopher Thomas Nagel published a paper titled What Is It Like To Be A Bat, introducing the idea that consciousness is defined by the subjective character of experience.
When did Roger Penrose and Stuart Hameroff propose the orchestrated objective reduction theory?
In 1994, physicists Roger Penrose and Stuart Hameroff proposed the orchestrated objective reduction theory, suggesting that consciousness originates at the quantum level inside neurons.
Which animals have been observed to pass the mirror test for self-awareness?
Humans older than 18 months, great apes, bottlenose dolphins, orcas, pigeons, European magpies, and elephants have all been observed to pass the mirror test for self-awareness.
What are the two most widely accepted altered states of consciousness?
The two most widely accepted altered states are sleep and dreaming, each associated with distinct patterns of brain activity, metabolic activity, and eye movement.
In 1974, the philosopher Thomas Nagel published a paper titled What Is It Like To Be A Bat, introducing the idea that consciousness is defined by the subjective character of experience. Nagel argued that there is something it is like to be a conscious organism, and that this subjective experience cannot be fully explained by objective physical processes. This became known as the hard problem of consciousness, distinguishing the question of how the brain works from the question of why it feels like something to be that brain. David Chalmers later expanded on this distinction, separating phenomenal consciousness, which is raw experience, from access consciousness, which is the ability to report and reason about that experience. Chalmers argued that while access consciousness can be understood in mechanistic terms, phenomenal consciousness remains a mystery. The problem of other minds adds another layer of complexity, as we can only observe the behavior of others, not their internal experiences. Philosophers debate whether we can ever truly know if another person, or even a philosophical zombie, has consciousness. Daniel Dennett has argued that the concept of a philosophical zombie is incoherent, suggesting that consciousness is entirely reflected in behavior. Despite these debates, the hard problem remains unsolved, with no consensus on how mental experience can arise from a physical basis.
The Theater Of The Mind
In 1988, cognitive psychologist Bernard Baars proposed the global workspace theory, using the metaphor of a theater to explain how consciousness works. In this model, conscious processes are represented by an illuminated stage, while unconscious processes form a broad, unlit audience. The theory suggests that the brain integrates inputs from various unconscious networks and broadcasts them to the rest of the brain, creating a unified experience. This global workspace allows for the integration of information from different sensory systems, explaining how our experience seems unified despite being composed of many separate parts. Stanislas Dehaene and Lionel Naccache have since expanded on this theory, providing evidence for the role of the prefrontal cortex in conscious awareness. The theory also addresses the binding problem, which asks how the brain links information from different parts of the brain into a single experience. Gamma oscillations, high-frequency brain activity, have been proposed as the mechanism that binds these disparate signals together. Rodolfo Llinás suggested that consciousness results from recurrent thalamo-cortical resonance, where specific and non-specific thalamocortical systems interact in the gamma band frequency. This model provides a framework for understanding how the brain creates a coherent narrative from the chaos of sensory input.
The Quantum Mind Hypothesis
In 1994, physicists Roger Penrose and Stuart Hameroff proposed the orchestrated objective reduction theory, suggesting that consciousness originates at the quantum level inside neurons. They argued that quantum processes occurring within microtubules, the cytoskeleton of neurons, account for creativity, innovation, and problem-solving abilities. Penrose published his views in the book The Emperor's New Mind, claiming that quantum phenomena play a role in human cognition. The theory gained new life in 2014 with the discovery of quantum vibrations inside microtubules, yet it remains highly controversial. Critics have pointed out flaws in Penrose's interpretation of Gödel's theorem and his conclusion that quantum phenomena are essential for consciousness. In 2022, an experiment led by Catalina Curceanu suggested that quantum consciousness is highly implausible, as empirical evidence contradicts the notion of wave function collapse in the brain. Despite these challenges, the theory continues to attract attention, with some theorists arguing that classical physics is intrinsically incapable of explaining the holistic aspects of consciousness. The debate over quantum mind theories highlights the difficulty of bridging the gap between the physical and the subjective, as no quantum mechanical theory has been confirmed by experiment.
The Evolution Of Awareness
The emergence of consciousness during biological evolution remains a topic of ongoing scientific inquiry, with opinions divided on when and how it first arose. Some argue that consciousness emerged exclusively with the first humans, while others suggest it appeared with the first mammals, birds, or even reptiles. Donald Griffin proposed a gradual evolution of consciousness, while Peter Godfrey Smith has explored the origins of consciousness in molluscs. The survival value of consciousness is still debated, with some arguing it is a by-product of evolution, as Thomas Henry Huxley suggested in his essay on animal automata. William James objected to this view, arguing that consciousness must have had a survival value itself, as it could only have been efficacious if it provided an adaptive advantage. Karl Popper developed a similar evolutionary argument in The Self and Its Brain, suggesting that consciousness allows an individual to make distinctions between appearance and reality. This ability would enable a creature to recognize the likelihood that their perceptions are deceiving them and behave accordingly. The integration consensus suggests that phenomenal states integrate neural activities and information-processing that would otherwise be independent, solving the classic problems of differentiation and unity. However, it remains unclear why any of this information is conscious, as many kinds of information can be disseminated and combined without consciousness.
The Mirror And The Self
In the 1970s, Gordon Gallup developed an operational test for self-awareness known as the mirror test, which examines whether animals can differentiate between seeing themselves in a mirror versus seeing other animals. The classic example involves placing a spot of coloring on the skin or fur near the individual's forehead and seeing if they attempt to remove it, thus indicating that they recognize the individual they are seeing in the mirror is themselves. Humans older than 18 months, great apes, bottlenose dolphins, orcas, pigeons, European magpies, and elephants have all been observed to pass this test. Contingency awareness, the conscious understanding of one's actions and their effects on the environment, is another factor in self-recognition. A study in 2020 involving transcranial direct current stimulation and magnetic resonance imaging supported the idea that the parietal cortex serves as a substrate for contingency awareness. The mirror test has become a standard tool for studying self-awareness in non-human animals, raising questions about the nature of consciousness across species. The test also highlights the importance of the medial temporal lobe and age in the brain processes during contingency awareness and learning. While the mirror test provides a practical way to assess self-awareness, it does not fully explain the subjective experience of consciousness, leaving the hard problem of consciousness unresolved.
The Altered States Of Mind
There are some brain states in which consciousness seems to be absent, including dreamless sleep or coma, while others can change the relationship between the mind and the world in less drastic ways. The two most widely accepted altered states are sleep and dreaming, each associated with distinct patterns of brain activity, metabolic activity, and eye movement. During ordinary non-dream sleep, people who are awakened report only vague and sketchy thoughts, and their experiences do not cohere into a continuous narrative. During dream sleep, in contrast, people who are awakened report rich and detailed experiences in which events form a continuous progression, which may however be interrupted by bizarre or fantastic intrusions. Thought processes during the dream state frequently show a high level of irrationality. Both dream and non-dream states are associated with severe disruption of memory, which usually disappears in seconds during the non-dream state and in minutes after awakening from a dream unless actively maintained. Altered states can also be produced by drugs or brain damage, leading to changes in thinking, disturbances in the sense of time, feelings of loss of control, and changes in emotional expression. The entropic brain theory suggests that the brain in primary states such as rapid eye movement sleep, early psychosis, and under the influence of psychedelic drugs, is in a disordered state. Normal waking consciousness constrains some of this freedom and makes possible metacognitive functions such as internal self-administered reality testing and self-awareness. These altered states provide a unique window into the nature of consciousness, revealing how the brain constructs our experience of reality.