Psychology 2800-001 September 19, 2013
Ways of Knowing
Part 1: How do we know?
Part 2: The scientific way of knowing
Part 1: How do we know?
Charles Pierce (1877): wrote an essay called The “Fixation of Belief”
Described several ways of ‘knowing’ / fixating belief
Relying on what authorities say (i.e. parents, professors)
But, authorities can be wrong
Parents can pass on incorrect information
Knowledge can be biased, incomplete or just completely wrong
B) Logical Discourse (the “a proiri” method)
Knowledge that is “agreeable to reason”
Example: deductive logical (syllogisms):
Begin with general premises (that are believed, a priori, to be true)
Deduce specific conclusion from these premises (new knowledge)
Together, the premises and conclusion form what’s called a syllogism
Example: Do Kangaroos of Livers?
Premise 1: All kangaroos are mammals
Premise 2: All mammals have livers
Conclusion: Therefore, it is logical to deduce that all kangaroos have liver
Problem #1: The premises might not be true
Thus any conclusion you draw from the premise would be wrong
- P1: Socrates was a Dog
- P2: Dogs are not human
- C: Socrates was not human
Problem #2: “Logical Errors”
- P1: All welfare is “giving to the poor”
- P2: All charity is “giving to the poor”
- C: All welfare is charity. But is it?
- P1: All Canadians are people
- P2: All Egyptians are people
- C: All Canadians are Egyptians ???
C) Empiricism: Relying on direct experience and observations
Problems occur when we rely too much on “subjective empiricism”:
Relying on informal, “intuitive” experiences and observations Psychology 2800-001 September 19, 2013
1. Knowledge we gain is too general (it describes everything, but predicts nothing)
E.g. Common Sense (conventional wisdom)
- Haste makes waste, BUT
o “he who hesitates is lost”
- “two heads are better than one”, BUT
o “too many cooks spoil the soup
Note: it’s not that common sense is wrong; instead, we don’t know when it’s right
- Don’t know the specific conditions when it applies
- So it can never be disconfirmed
2. Subjective experiences and observations are often biased
The availability bias: occurs when judging the frequency of events
People assume that events that are easily available in memory are also more frequent
But this is not always the case!
Example 1: Some events are easier to retrieve from memory, even though this has nothing to do with
their frequency in the real world
E.g. in the English language: which is more frequent?
1) Words beginning with the letter “k” OR
2) Words with “k” as the third letter
Most people choose (1) because they’re easier to retrieve from memory, but (2) is more than twice
Example 2: Some events are easier to imagine (makes them available in memory, so judged to be more
E.g. which is more frequent cause of death
1) Being killed by “shark attack” OR
2) Being killed by “falling airplane part”
Most people choose (1) because it’s easier to imagine, but (2) is 30 times more likely!
Example 3: We’re exposed to biased samples of events (which makes them more available)
E.g. smokers overestimate the number of people who smoke (because they see more smokers)
Are you more likely to die from
1) A car accident OR
2) Stomach cancer?
(2) I the correct answer, but most people say (1). Why?
People are more likely to hear about car accidents in the media (provides a biased sample)
For additional examples of biases, see:
Ch4: the “viv