Overview
This lecture critiques the explanation that ghosts are spirits and explores alternative scientific explanations for ghost experiences, focusing on physical, psychological, and environmental causes.
Problems with the Spirit Explanation
- Seeing objects requires light bouncing off atoms, but if ghosts aren't made of atoms, it’s unclear how we could see them.
- If ghosts were made of atoms, they couldn ’t pass through walls, as reported in many encounters.
- Ad hoc reasoning is used when people claim ghosts are made of “ectoplasm” or unknown forms of energy to save the spirit theory.
- Introducing extra entities without independent evidence makes theories less simple, violating the criterion of simplicity.
- Ghosts are often reported wearing clothes, but it doesn’t make sense for clothing to have spirits or appear in ghost form.
Alternative Explanations for Ghost Experiences
Sleep Paralysis and Narcolepsy
- Many ghost encounters happen as people are falling asleep or waking up and often involve an inability to move.
- Sleep paralysis occurs when the body is immobilized during REM sleep, sometimes while the person is still conscious.
- REM sleep mixed with consciousness can blend dream imagery with reality, explaining some ghost experiences.
- Narcoleptics, who enter REM sleep quickly, report more ghost experiences, supporting the sleep paralysis explanation.
Environmental Factors
- Studies at famous haunted locations in England found cold drafts, electromagnetic activity, and other environmental anomalies at sites where ghost experiences are reported.
- Instruments detected environmental changes in locations considered haunted, matching where people sensed “ghostly” presence.
Electromagnetic Fields
- The "God Helmet" experiment showed that electromagnetic stimulation of the brain can cause ghostly or spiritual experiences in 80% of participants.
- More ghost reports occur during sunspot cycles, which alter Earth's magnetic field.
Sound Waves and Infrasound
- Infrasound (below 20 Hz) can cause physical sensations and visual distortions, including vibrating objects and eyeballs, leading to ghostly experiences.
- Wind, thunderstorms, and appliances can naturally produce such infrasound.
Pareidolia and Pattern Recognition
- The brain is wired to detect patterns, sometimes seeing faces or figures where none exist (pareidolia).
- Auditory pareidolia can make people perceive voices or music in random noises, such as from a fan.
Key Terms & Definitions
- Ad hoc reasoning — Creating additional assumptions to save a theory without independent evidence.
- Sleep paralysis — Temporary inability to move or speak while falling asleep or waking up, often with hallucinations.
- REM sleep — Rapid eye movement sleep; deepest sleep stage with vivid dreaming.
- Pareidolia — Tendency to perceive a meaningful pattern, such as faces, in random stimuli.
- Infrasound — Sound waves below the threshold of human hearing, sometimes causing physical and perceptual effects.
Action Items / Next Steps
- Review the criteria of adequacy for evaluating theories, especially simplicity.
- Read up on sleep paralysis, electromagnetic field effects, and pareidolia for deeper understanding.