Critical Thinking or How to be a Really Good Pain in the Ass

1
Critical Thinkingor How to be a Really Good Pain
in the Ass

• Scientific Reasoning
• Scire to know

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Time Line
• Big Bang 12 15,000,000,000 years ago
• Prokaryotes 3,500,000,000 years ago
• Sexual reproduction 1,000,000,000 years ago
• Multicellular organisms 750,000,000 years ago
• Vertebrates (bony fish) 395,000,000 years ago
• Land reptiles 350,000,000 years ago
• Primates 65,000,000 years ago
• Australopithecines 7,000,000 years ago
• Homo sapiens 2,000,000 years ago
• Agriculture 10,000 years ago
• Personal computer 25 years ago

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Do you agree with the methods that scientists
  have used to reach their conclusions?
• Why are scientists entitled to hold the beliefs
  which they hold? Are they justified?
• Are scientists good authorities?
• If you disagree with this, you must show how some
  hidden premises are lacking in acceptability,
  relevance or sufficiency

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• The Influence of Science
• Are you reading by artifical light (V IR) or by
  natural light (e mc2)?

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• How is steam produced?
• IF we could come up with a better way of creating
  electricityTHEN we would be likely to create
  less pollution from burning fossil fuels or
  nuclear waste

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Y2K scenario (or the Blackout of August/2003)
• No lights, radio, TV, toaster, cooker, washer,
  dryer, air conditioning, heating, movie, stores,
  stereo, well pumps, telephone, computer, car,
  bus, plane

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Scientific subjects can be separated into two
  distinct areas
• Theoretical knowledge of the universe
• Invention, development and use of technology

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Theoretical knowledge of the universe
• Will the universe expand forever?
• What happened in the first few nanoseconds?
• Are quantum theory and general relativity
  incompatible?

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Invention, development and use of technology
• Do cigarettes cause lung cancer?
• What causes global warming?
• Should we clone humans?
• Whats wrong with GM corn?

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• A Well Informed Skeptic is a Dogmatists Worst
  Nightmare
• We need some way to understand the complex and
  diverse world in which we live
• Scientific knowledge is characterized by
  universality and objectivity
• Scientific knowledge has a track record of
  success in predicting novelty
• Scientific knowledge possesses the greatest
  explanatory power of all our current methods of
  knowledge
• Therefore science is the best method for
  attaining knowledge that we humans have

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• The trickle-down effect of scientific information
• Professional journals, conferences
• Scientific American, Discovery, The Sciences
• The Globe and Mail, Toronto Star
• CNN, The Discovery Channel, Nova
• The school playground

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Q. Do we need to be scientists to understand
  scientific reasoning?
• Does an art critic need to be an artist?
• Does a hockey commentator need to have been a
  player?
• Could Howard Cosell fight?

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Causality is not Correlation
• A correlation is a statistical relationship
  between two variables, A and B. The correlation
  may be
• Positive grade students who take piano lessons
  do better in math than those who dont
• Negative grade students who watch a lot of TV
  tend to do badly in math tests
• Neutral Blue eyed people score the same in math
  tests as brown eyed people.

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Causality suggests correlation
• There are two types of causal condition
• Constant or necessary condition IF combustion
  occurs THEN oxygen must be present (i.e. Oxygen
  is necessary for combustion)
• Variable or sufficient condition Dry leaves and
  oxygen require ignition before they combust.

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Combined or Total Cause
• The set of necessary and sufficient (constant and
  variable) conditions
• The fire was caused because oxygen was present
  and the leaves were ignited

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• A controlled experiment may allow us to establish
  a causal relationship
• The subjects of the experiment are divided into
  two groups, the Test or Experimental Group and
  the Control Group which statistically represent
  the population of concern to the experimenters
• The outcome of the experiment is inferred by
  comparing the test group with the control group

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Experimenters have to be sensitive to the
  possibility that an experiment may be tainted,
  biased, affected by the subject or otherwise have
  its objectivity reduced. This can be done by
  blinding an experiment, which mean that the
  subjects and possibly the researchers do not know
  which is the test and which the control group

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Often a placebo is given to the control group to
  enable researchers to distinguish trial outcomes
  from other outcomes of the experiment

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Scientific explanations Induction
• We infer that past events are a guide to future
  events
• We move from observing particular events towards
  inferring generalizations
• We move from general accounts to particular
  accounts of a phenomenon
• Induction is not logically watertight, as is
  deduction, but it frequently works

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Explanations Why do things behave the way they
  seem to?
• Hypotheses
• Models
• Theories
• Laws

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Hypotheses are educated guesses
• Models are analogies
• We compare the unfamiliar to something that is
  familiar
• A model may be abstract (e mc2)
• A model may be physical (the orrery)
• A model may be a map

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• A theory is the strongest type of scientific
  explanation
• The Big Bang theory
• Einsteins theories of special and general
  relativity
• Quantum theory
• Darwins theory of evolution through natural
  selection

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• A scientific law, or law of nature, is a rule by
  which (some part of) the universe functions
• Newtons laws
• Keplers laws of planetary motion

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Scientific Methodology
• There are and have been many forms of scientific
  methodology
• Memes transfer information across groups and
  across cultures
• Some survive, some get lost or destroyed
• The memes of science which survive over time form
  scientific methodology

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Scientific methodology
• We make an observation of the phenomenon
• We then speculate about the causes of the
  phenomenon and form hypotheses
• We make predictions about what would happen if
  the hypothesis were correct
• We conduct experiments, make observations and
  collect data

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• We compare the data to the prediction and make
  one of three assessments
• If the data matches the prediction we assume the
  hypothesis is confirmed
• If the data does not match the predicted outcome,
  the hypothesis is disconfirmed (falsified)
• We may suspend judgement (more research needed!)
  if we cannot decide between the two previous cases

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• We must consider if there is some competing
  hypothesis which would appear to present an
  equally plausible explanation of the phenomenon
  and the experimental data, and determine which
  hypothesis seems more plausible

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Critical Thinkingor How to be a Really Good Pain
in the Ass
Observation
Hypothesis
Prediction
Experimentation/Data collection
Confirmation
Falsification
Suspend Judgement
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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Example of Scientific Reasoning The case of the
  missing dinosaurs
• Observation There are no dinosaurs alive on
  earth
• Observation The fossil record indicates that 65
  mya dinosaurs rapidly became extinct
• To be explained What caused such a rapid
  extinction?

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Three dinosaur hypotheses
• Disease
• Meteor
• Ice age
• Q. Which is the correct hypothesis?

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• What predictions can we make from each
  hypothesis?
• Disease We may find signs of bacteria or viruses
  in dinosaur or other fossils from 65 mya
• Meteor We may find traces of non-earth elements
  in the fossil record
• Ice Age We may find indicators of rapid climate
  change in the fossil record

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Data Luis and William Alvarez have found traces
  of iridium dating from 65 mya at many sites
  around the world

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• We are more justified in accepting the meteor
  hypothesis than either of the other 2

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Scientific Claim Analysis (p. 106)
• Observation
• Hypothesis (educated guess)
• Prediction(s)
• Experimentation/Data collection
• Observation
• Confirmation
• Falsification
• Suspend Judgement
• Competing Hypothesis

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Scientific Studies Asking the right question(s)
  (p. 109)
• Who conducted the study?
• What was the motivation for the study?
• Who funded the study?
• What was the methodology of the study?
• Is the study repeatable?

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Causal Fallacies in Science
• Confusing cause and effect
• Every time I take my umbrella to work it rains
• So my taking my umbrella causes it to rain
• Common cause
• The babys been crying all night, the same as she
  did a week ago when we gave her strained pears.
• It must be the pears we gave her tonight which
  made her cry.

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• More Scientific Fallacies
• Post hoc ergo propter hoc
• Every week I put the garbage on the curb and then
  the truck comes round to collect it, so my
  putting the garbage out must cause the garbage
  truck to come round
• Air raid sirens prevent tornadoes!
• Homer Simpson buys a rock
• Wear a clown suit when you drive!

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Pseudoscience
• Astrology
• Phrenology
• Telekinesis
• Water dowsing
• Clairvoyance

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Critical Thinkingor How to be a Really Good Pain
in the Ass

• Fallacy of Argumentum ad Ignorantiam
• Scientists have not shown astrology to be false
• Therefore, astrology is true
• It is the responsibility of the person making
  such a claim to provide proof that it is true,
  not to assume it