Philosophy of Consciousness

Consciousness

• Consciousness is the most perplexing problem in the science of the mind.
• There's no universally accepted definition in science or philosophy, despite many attempts.
• The word "consciousness" is used differently in everyday language. It can refer to being awake/responsive, or being aware of something, or even a subjective personal experience.

The Hard Problem of Consciousness

• Chalmers coined the phrase "the hard problem of consciousness" (1995).
• "Easy problems" are cognitive functions which can be explained by cognitive models or neuroscience.
• Subjective experiences (the hard problem) accompany these cognitive functions.
• The hard problem is also known as the mind-body problem.
• It asks how physical processes give rise to subjective experience, and how the mind interacts with the physical body.
• Chalmers describes easy problems in relation to consciousness.

The Mind-Body Problem

• The mind-body problem seeks to explain how physical processes result in mental ones, and how they interact.
• Leibniz (1714) argued that machines could not explain perception, due to it being fundamentally different to mechanism.
• Nagel (1974) posed the question "what is it like to be a bat?".

Defining Consciousness

• Dehaene et al. (2014) offer several possible aspects:
  • Conscious content: what one is aware of at a specific moment
  • Conscious access: processes of becoming conscious of content
  • Conscious processing: operations applicable to conscious contents
  • Conscious report: process of describing contents
  • States of consciousness: ability to entertain a stream of contents.

Measuring Consciousness

• Modern approaches aim to identify neural correlates of consciousness (NCCs).
• Various states of consciousness are compared: e.g. asleep vs. awake; anesthetized vs. awake, cases with disorders of consciousness.
• Tools like Coma recovery scale and Glasgow coma scale help assess consciousness levels.
• Vegetative state: wake-sleep cycle (eyes open and some motor activity, eyes closed and sleep); reflexes, but no communication.
• Minimally conscious state: some responsiveness and communication.

Neural Correlates of Consciousness

• Global Workspace Theory (Dehaene, 2006): conscious states depend on global availability of information.
• Neural Darwinism (Edelman): neural structures firing in synchrony, forming the basis of brain function.
• Long-distance connections and synchronised neuronal activity are key to consciousness.
• Thalamo-cortical loops are crucial for integrating sensory input and sub-cortical activity.

Cognitive Processes Associated with Consciousness

• Re-entrant processing: feedback projections are important in consciousness, as well as prediction and comparison of input.
• Integrated and differentiated neural activity are significant for consciousness: integrated neural activity shows synchronicity across regions. Differentiated neural activity expresses complexity.

Neurological Disorders and Consciousness

• Individuals with disorders of consciousness demonstrate differences in cognitive processes and brain activity.
• Information sharing in the brain influences consciousness, particularly in centroposterior regions.
• Perturbation studies, like TMS and EEG, help to identify neural correlates. These neuroimaging technologies can assess consciousness by detecting information sharing.
• PCI, a complex indicator of consciousness, is measured reliably on individuals.

What We Know About Consciousness

• Defining consciousness remains a difficult task, although several approaches provide insights into its neural correlates.
• There is a need for correlational and causal studies for better understanding conscious experience.