Hannah Critchlow - Consciousness

We are all unique. Each person on this planet holds their own, highly individual sense of reality shaped by their distinct set of past memories. As a result, we all experience the world, and respond to it, in our own way. This individualized experience underpins the essence of consciousness: to be aware of our surroundings, hold a subjective view of the world, and then interact with the environment with our own perspective.

How such consciousness arises has been debated for centuries. Traditionally, this was the domain of philosophers, working mainly in the realm of the theoretical. Recent technological advances have, however, made it possible to produce objective measures of consciousness, to visualize its development and to observe what happens as it fails; scientists have joined in the study.

As we understand more precisely how the brain operates, it would seem inevitable that we should get closer to a straightforward explanation of consciousness. Yet, paradoxically, for many this knowledge increases the allure and mystique of the phenomenon, challenging our current definition of consciousness as perhaps too simplistic. Our increased knowledge also produces pressing ethical considerations are other animals, or even plants, conscious? Can we create conscious robots? If so, should they have the same legal rights as humans? Can we enhance our own levels of consciousness? Is it possible to invoke a shared collective consciousness? And as we understand more about the nature of consciousness, what are the ramifications for the concept of free will? Perhaps even our ability to ponder and debate these issues forms a part of what it means to be conscious

As they tried to understand how consciousness forms, philosophers were first fascinated by the question of where in the body it arose.

In the fourth century BC, Aristotle reasoned that since the heart is vital for life, consciousness must originate there. Around 500 years later Galen, the Greek physician, surgeon and philosopher, moved upwards. He conducted numerous dissections and, as his anatomical knowledge grew, so did his appreciation for the brain. Galen believed that consciousness lived in the clear, colourless liquid that surrounds and cushions this organ. Galen called it the psychic pneuma, a magical fluid that acted as the breath of life and instrument for the soul.

In the sixteenth century AD, Descartes continued with Galens hypothesis that consciousness arose in the brain, but focused its source on the tiny pineal gland located at the brains centre. He believed this structure opened when you looked up so that animal spirits of memory were permitted entry. He reasoned that looking to the ground closed off these memory spirits, thereby allowing deep conscious thought. Descartes argued that the physical world (the chair you are sitting on, the apple you are eating) is entirely separate to the non-physical world of your individual perceptions and sensations (the feeling of the cold, hard seat on your legs, the satisfying crunch of the apple as you take your first bite, the fresh smell and sweet taste that you experience). He proposed that the pineal gland allowed communication between these two worlds to enable you to experience sensations and form your unique view of the world. This theory is known as Cartesian dualism reflecting the idea that the body and the mind occupy separate realms.

In order to probe the nature of consciousness, philosophers would conjure up thought experiments: using imagined scenarios to uncover the nature of reality.

One of the most famous thought experiments on consciousness is What is it like to be a bat?, debated by the philosopher Thomas Nagel in 1974. He argued that since consciousness is the ability to form a subjective view of the world, it is useful to imagine being something. For example, if you want to know if a table is conscious, then ask yourself, what is it like to be a table? Most people would concur that a table cannot feel or think, that it is simply a physical item and so does not hold a unique view of the world. A table is just unconsciously there.

But what about a bat? Can you imagine what it might be like to fly around the night sky, relying on echoes to navigate, eating bugs, then sleeping upside down? What would it be like to be a bat? If you can start to answer this, then bats are conscious, Nagel argued. What about a bamboo plant? A fruit fly? A bumble bee? A cucumber? Or a computer? Can you imagine being these? If so, perhaps they are also conscious.

Nagel took this thought experiment a step further by suggesting that if you were able to metamorphose into a bats body, you would still not be a true bat because you were not born a bat. You would retain your human perspective and therefore could never possess a bona fide bat mindset. You would be more like a manbat, with a bat body and human mind.