Overview
This lecture surveys philosophical and scientific approaches to the "hard problem" of consciousness, including theories, experiments, and foundational debates.
Approaches to the Hard Problem of Consciousness
- The "hard problem" refers to explaining subjective experience or why consciousness exists.
- Approaches include denying it can be solved, trying to solve it, focusing on "easy" problems, identifying more hard problems, denying its existence, or reframing it as a meta-problem.
Key Theories and Philosophers
- Patricia Churchland advocates eliminative materialism: some mental phenomena (like qualia) might not exist.
- Daniel Dennett argues against qualia and dualism, claiming "we're all zombies."
- Crick and Koch seek neural correlates of consciousness (NCCs) via brain scans and brain state changes.
- Penrose suggests consciousness arises from quantum effects in brain microtubules.
- Tegmark proposes consciousness as a new state of matter and a mathematical pattern.
Qualia and Thought Experiments
- Qualia are private, subjective experiences (e.g., the taste of beer).
- The "Mary" thought experiment questions if knowing all physical facts about color includes knowing what color experience is like.
- Philosophical zombies are beings indistinguishable from humans but lack consciousness.
Representational and Functionalist Theories
- Higher-order theories (David Rosenthal, Josh Weisberg, Rocco Gennaro): a mental state is conscious when it is the object of higher-order thought or perception.
- Functionalism (Hilary Putnam): mental states are defined by their functional roles; any system with similar functions could have consciousness, including machines.
Conscious vs. Unconscious Events
- Conscious events: perception, novel stimuli, voluntary attention, supraliminal stimuli, retrieved memories.
- Unconscious events: pre-perceptual processing, habituated stimuli, unattended/subliminal stimuli.
Global Workspace Theory & Contrastive Analysis
- Bernard J. Baars proposes the Global Workspace Theory: consciousness involves broadcasting information to multiple brain systems.
- Contrastive analysis/phenomenology distinguishes conscious from unconscious processing.
Attention and Perception
- Treisman's Feature Integration Theory: perception involves pre-attentive processing followed by focused attention.
- Visual search experiments illustrate differences between conscious feature detection and conjunctive search.
- Inattentional blindness: failing to notice unexpected objects (like a gorilla in a ball-passing video).
- Cocktail party phenomenon: selective attention to one conversation among many.
- Dichotic listening shows how we process attended vs. unattended information.
Key Terms & Definitions
- Hard problem — the challenge of explaining why and how subjective experience arises.
- Qualia — private, subjective experiences of perception.
- Philosophical zombie — hypothetical being indistinguishable from a human but without consciousness.
- Higher-order theory — consciousness arises when a mental state is the object of higher-order thought or perception.
- Functionalism — mental states are defined by their functional roles, not by their substance.
- Global Workspace Theory (GWT) — consciousness emerges from widespread sharing of information across the brain.
- Inattentional blindness — failure to notice visible stimuli when attention is elsewhere.
Action Items / Next Steps
- Review Global Workspace Theory and contrastive analysis in next reading.
- Reflect on the difference between conscious and unconscious mental events.
- Prepare for discussion on thought experiments (Mary, philosophical zombie).