The document discusses sources of knowledge and errors in thinking that can distort critical thinking. It explains that knowledge comes from both rationalism, which sees knowledge coming from reason, and empiricism, which sees it coming from sensory experience. However, Immanuel Kant argued that our experience is dependent on how our minds structure information. The document also outlines various cognitive and perceptual errors that can influence human judgment, such as confirmation bias, distortion, and errors arising from social and group influences. Overall, it emphasizes that critical thinkers must be aware of the limitations of human reason and experience in order to evaluate information objectively.

1. KNOWLEDGE, EVIDENCE,
& ERRORS IN THINKING
The aim of this tutorial is to help you learn to
understand the sources of knowledge used in
critical thinking.

2. Good critical thinking skills require a
sound knowledge base
Knowledge is information or experience we believe
to be true and for which we have justification or
evidence.
Understanding how knowledge is acquired, as well as
having an awareness of the limits of human understanding,
is essential in logical reasoning.
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3. Rationalism and empiricism
Our views of the world are shaped by our
understanding of truth and the ultimate sources of
knowledge.
Rationalists, like the Greek philosopher Plato, claim that
most human knowledge and truth derives from reason.
Empiricists, on the other hand, claim that truth and
knowledge are derived through empirical evidence
collected by our physical senses.
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4. Immanuel Kant (1724-1804)
Kant, a German philosopher, rejected both rationalism
and empiricism.
He argued that our experience of reality is not a matter of
reasoning or empirical evidence, but is dependent on the
structure of our minds.
This means we do not see reality “as it is,” but rather
as our brain interprets it by structuring and processing
incoming information.
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5. Evaluating evidence
 Evidence is something that tends to prove or disprove a
particular view.
 It can come from a variety of sources, and as good
critical thinkers we must evaluate all evidence before we
employ it in critical analysis.
 Learning how to evaluate the credibility and accuracy of
evidence is a key skill in critical thinking and logic.
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6. The fallibility of direct experience
 As noted previously, our brains organize and interpret,
rather than directly record, sensory experience.
 As a result, direct sense experience, while widely relied
upon, is not infallible. Memories are subject to influence
from a range of factors, including time, language, and
external suggestion. Also, our brains often create false
memories of events, and these false memories can be
as compelling and believable as real memories. This
phenomenon is known as false memory syndrome.
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7. Many of the witnesses of the 1986 Challenger explosion
dramatically altered their memories of the disaster, even
“seeing” things that never happened.
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8. The 2002 Beltway sniper had been using a blue
car, not the white van “seen” by an eyewitness.
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9. Hearsay and anecdotal evidence
 Two types of evidence are notoriously unreliable and
require us to approach their claims with skepticism:
 Hearsay evidence is evidence that is heard by one
person, then repeated to one or more other persons.
 Anecdotal evidence, evidence based on personal
testimony, is also unreliable due to problems of inaccurate
memory, as well as the human tendency toward
exaggeration and distortion.
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10. Hearsay and the game of Telephone
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11. Experts and credibility
 Although experts are generally among the most credible
information sources, it is always important to examine
their credentials before accepting their arguments.
 Four factors used to determine expertise:
 Education or training from a reputable source
 Experience in making judgments in the field
 Reputation among peers in the field
 Accomplishments in the field, such as publications and/or
awards
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12. Inadequate research can lead to
misrepresentation of a product.
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13. Evaluating claims
 Our analysis of the evidence for a claim should be
accurate, unbiased, and as complete as possible.
 One thing we must watch out for when evaluating claims
is confirmation bias, the tendency to look only for
evidence that confirms our assumptions and to resist
evidence that contradicts them.
 As critical thinkers, we need to consciously develop
strategies that compel us to examine evidence—
especially that which confirms our prior views—more
skeptically, and to be more open-minded about evidence
that contradicts our views.
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14. Joe Scarborough on socialism vs. capitalism
and Olympic medal winners
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15. Hot or Not?
Do you tend to distort evidence to
fit with your beliefs?
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16. Research is the key to knowledge
 Good critical thinkers spend time researching claims and
collecting information before drawing conclusions.
 Recommended research resources
 Expert interviews
 Dictionaries and encyclopedias
 Library catalogues and scholarly journals
 Government documents and Internet sites
 When doing research, take accurate notes, cite your
sources, and use quotations to acknowledge sources.
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17. Rachel Carson
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18. The Da Vinci Code
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19. Cognitive and perceptual errors in
thinking
 Most people underestimate the critical role that cognitive
and social factors play in our interpretation of sensory
data.
 Although emotion has traditionally been blamed for
faulty reasoning, studies suggest many of our errors in
thinking are neurological in nature.
 Most of these errors are either cognitive or perceptual
errors.
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20. Perceptual errors
 Our minds are not like recording devices. Instead, our
brains construct a picture of reality like an artist does,
filtering our perceptions and filling in missing information
based in part on our expectations.
 These processes result in a number of perceptual error
predispositions, including distortion of objects,
misperception of random data, memorable events error,
probability errors, self-serving biases, and self-fulfilling
prophecies.
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21. War of the Worlds
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22. The St. Louis Arch
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23. Inkblots
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24. Radar photo of 2005 Hurricane Katrina, which
some saw as similar to the image of a fetus in the
womb and concluded the storm was punishment
for the presence of abortion clinics.
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25. Statistically, there is a greater chance of being
killed in a car accident than in an airplane crash.
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26. Gambler’s error is based on a misunderstanding of
the random nature of probability.
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27. Irrational beliefs and depression
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28. Rumors of impending bank failures during the
Great Depression led to mass panic.
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29. Social errors and biases
 As highly social animals, social norms and cultural
expectations exert a strong influence on how we
perceive the world. These norms and expectations often
act as barriers to critical thinking.
 Some examples of social errors include the
“one of us / one of them” error, social expectations,
stereotyping, group pressure and conformity, and group
diffusion of responsibility.
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30. Much of the violence between conflicting cultural
groups is born of the “One of Us/One of Them” error.
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31. Red states vs. blue states
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32. The Salem witch hunts targeted those mistakenly
believed to be responsible for society’s ills.
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33. Asch experiment
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34. “Diffusion of responsibility” was illustrated
when no one came to the aid of a hit-and-run
victim in 2009.
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35. Conclusions
Although knowledge is a crucial component of effective
critical thinking, we must recognize that the sources of
knowledge, reason, and experience are subject to
distortion.
As critical thinkers, we must be aware of these limitations
and conduct research thoroughly, with minds open to both
supportive and contradictory evidence as we collect and
analyze information.
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36. Peter Reilly
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