book science knowledge

The Skeptics' Guide to the Universe


  • The essence of skepticism --> How to we know what to believe and what to doubt?
  • How do we know anything?
  • Things this book aims to teach:
    • How our brains fail us
    • How we prefer simple/clean stories
    • How bad our memory is
    • How biases impact our thinking
    • Failures of society
    • Imperfections in the institutions of science, learning, and journalism
  • Cynicism is cheap
    • It holds back progress
  • Skeptics combine science, philosophy, psychology, and all the flaws/biases of being human to evaluate claims and beliefs

1. Scientific Skepticism

  • See also: Critical thinking
  • Term was coined by Carl Sagan
  • Approach to knowledge that prefers beliefs and conclusions that are reliable and valid over anything comforting or convenient
  • Scientific skeptics rigorously apply science to reason about their thoughts and opinions
  • Different from philosophical skepticism
    • Philosophical skepticism is a position of almost permanent doubt
      • Can we actually know anything?
      • What is the nature of knowledge itself?
  • Start with doubt and try to separate truth from fantasy, wishful thinking, biases, and tradition
  • Tools used to parse reality:
    • Respect for knowledge and truth
      • Try to be as reality-based as possible
      • Subject claims to a rigorous process of evaluation
      • The world is knowable due to the laws of nature
    • Promotion of science
      • Science is the only legitimate way to investigate and understand the natural world
      • We must defend and spread the use and understanding of scientific methods
    • Promotion of reason and critical thinking
    • Science vs pseudoscience
      • Seek to expose pseudoscience
      • You must understand how science can go wrong
    • Ideological freedom / free inquiry
      • Science and reason can only flourish when ideology is not imposed
    • Neuropsychological humility
      • We must know how we deceive ourselves, the limits of our perception and memory, the biases and fallacies of our cognition, and how to mitigate all these flaws
    • Consumer protection
      • Expose fraud and deception
      • Combat misinformation

2. Memory Fallibility and False Memory Syndrome

  • See also: Perception, Self-deception
  • Memories are constructed from our imperfect perceptions filtered through beliefs, biases, and morphed over time
    • They are the stories we tell ourselves
  • We give preference to things we perceive that reinforce continuity
  • Declarative memory
    • Explicit memory
    • Factual knowledge stored in long-term memory
    • Consciously recalled
    • Episodic memory
      • Autobiographical memory
      • Memory of events in our lives
    • Semantic memory
      • Factual memory about the world
      • Two components stored separately
        • Truth status of something (is it true or false?)
        • The source of the memory
  • Procedural memory
    • Implicit memory
    • Automatic
    • Involves learning to do motor tasks (throwing a ball, etc.)
  • It's always good to be skeptical of our own memories

Memories are Malleable

  • Memories are flawed during construction and get worse over time
  • Recalling a memory involves reconstructing and updating it
  • "Lost in the mall" study
    • People were given a pamphlet that contained memories from childhood
    • 3/4 memories were true
    • 29% "remembered" the false story with vivid detail
  • Many adults can be convinced they committed a nonexistent crime after just three hours of police interrogation
  • We often contaminate each other's memories if we discuss them
    • Court room witnesses can't meet because of this

False Memory Syndrome

  • Construction of false memories
  • Accomplished through:
    • Guided imagery
    • Hypnosis
    • Suggestion
    • Group pressure

3. Fallibility of Perception

  • Perceptions are not a passive recording of the world
    • Optimized for functionality
  • Your brain "patches" blindspots in your vision
    • Only the fovea records images in details
      • The fovea is very small
  • Our brains project movement into the future to account for delays in processing time
  • Alien hand syndrome
  • Inattentional blindness
  • Change blindness

4. Pareidolia

5. Hyperactive Agency Detection

  • Coincidence
  • Tendency to interpret events as if caused by a conscious agent instead of natural forces or chaotic events
    • Often leads to conspiracy theories
  • May be important to the development of religion

6. Hypnagogia

  • Hypnagogia
  • Often paired with sleep paralysis
    • ~8% of people experience sleep paralysis
  • "maere" is Old English for "female demon who suffocates people in their sleep"
    • This is where "nightmare" is derived from

7. Ideomotor Effect

  • Subtle muscle movement driven by expectation
  • This is how dowsing rods work

8. Dunning-Kruger Effect

  • Duning-Kruger effect
  • Overconfidence bias
  • Always assume you know a little less than you think you do

9. Motivated Reasoning

  • The biases process of defending something we are emotionally attached to
  • Triggered by cognitive dissonance
  • We need to make concerted effort when thinking about things related to ideology
    • Factual beliefs about the world shouldn't be a source of identity (they may need to be updated/changed)
  • Always remind yourself that the people disagreeing with you are people
    • They have reasons to believe what they do just like you do
    • Everyone has their own narrative