Notes Chapter 2

Evaluating Claims to Knowledge

Clever Hans

•       Clever Hans was a horse with the seeming ability to solve mathematical problems.

•       It appeared that Hans could solve these problems to

    eyewitnesses

Hans

•       Psychologist Oskar Pfungst put Hans to the test.

•       Under controlled conditions Pfunst found that Hans could only answer correctly if two certain conditions were met.

•       1. The individual asking the question had to know the correct answer

•       2.  Hans had to have an unobstructed view of the person asking the question

Hans (cont.)

•       When either of the two conditions were controlled for (not allowed) Hans could not answer  the question correctly.

•       So how did Clever Hans do it?

Hans (cont.)

•       Hans was a remarkable animal. 

•       Hans could tell by the tone of an individual’s voice a question was being asked.

•       Hans began tapping his hoof and watched the individual who had asked the question.

•       When the correct answer was given by Hans the observer unconsciously tilted their head.

•       Hans recognized this and stopped tapping.

•       Hans was a an excellent reader of nonverbal behavior.

The Observer-Expectancy Effect

•       The observer-expectancy effect (also called the experimenter-expectancy effect, observer effect, or experimenter effect) is a cognitive bias found in science that occurs when a researcher expects a given result and therefore unconsciously manipulates an experiment in order to find it.

•       So expecting Clever Hans to succeed led to unconscious signaling and Hans his successfully completing of his task.

•       The risk of Clever Hans effects is one strong reason why psychologists normally test animals in isolated apparatus, without interaction with them.

Clever Hans foiled!

•       Pfungst prevented the individual presenting the problem from knowing the answer and also blocked Hans view of the individual. 

•       Hans could no longer solve any of the problems.

•       It took the scientific method to find out if Hans was truly a math genius horse or not.

Scientific Reasoning

•       James Lett outlined a series of six tests that a claim must meet to warrant belief. 

•       Each test reflects an essential component of scientific thinking that can protect us from foolish beliefs.

•       FiLCHeRS – Falsifiability, Logic, Comprehensiveness, Honesty, Replicability and Sufficiency

Falsifiability

•       A claim must pose a hypothesis that can be disproved.

•       If a claim is false there must be a way to demonstrate it falsity. 

•       This is termed the falsifiability of the claim.

•       Without falsifiability a claim would be insulated from reality

Falsifiability (cont.)

•       Falsifiability (or refutability or testability) is the logical possibility that an assertion can be shown false by an observation or a physical experiment. "Falsifiable" does not mean false; rather, it means that something is capable of being shown to be false in the event that contrary examples or exceptions to the assertion actually exist. Falsifiability is an important concept in science.

Example

•       Carl Sagan (1995) used the example of a dragon to show how empty an unfalsifiable claim can be.

•       He suggested that he has a fire-breathing dragon in his garage. 

•       How would you test this?

Example /Carl Sagan

•       Question: Can I see it?  Ans: It is invisible.

•       Question: Could I use paint to make it visible?  Ans:  It is not a physical being so paint won’t stick to it.

•       Question: Could I put flour on the floor to see footprints?  Ans: The dragon floats in the air so it won’t leave footprints.

•       Question:  Could I measure the heat of the dragon’s breath? Ans:  It is a heatless flame.

•       Reasonable questions – Evasive Answers

•       If it is invisible, immaterial, hovers in the air and breathes out a heatless fire – how is this different from no dragon at all!

•       This is an example of an unfalsifiable claim.

Show Me

•       Scientists take on a “Show Me” attitude

•       Failure to meet the challenge of “Show Me” relegates a claim to the realm of Pseudoscience. 

•       Pseudoscientists protects their beliefs by framing unfalsifiable hypotheses.  Hypothesis that are unable to be disproved and asks you to accept these hypothesis on faith alone.

Scientists

•       Scientists achieve progress in their fields by eliminating mistaken ideas by careful scientific testing.

•       Use experiments to eliminate these mistaken ideas one by one.

•       This requires not that the hypotheses be false, but that if they are untrue, to be falsifiable 

LOGIC

•       Claims to knowledge must be logically sound.

•       Logical Arguments must satisfy two criteria: 

•             Premises on which the argument is based  must all be true    

•             Proposed conclusion must validly follow from the premises

Crop Circles

•       Your text gives the example of crop circles

•        Argument:  Crop circles constitute evidence extraterrestrial visits

•       Evidence: 

1.  Crop circles are extremely complex and numerous

2. Human beings are incapable of such complexity on so grand a scale

3. Therefore, crop circles are made by extraterrestrials

Crop Circle Argument

•       The first premise - Crop Circles are extremely complex and numerous -  is true.

•       The second premise – Human beings are incapable of such complexity on so grand a scale –  is false.  Two men have confessed to the hoax and have shown reporters how to create the crop circles using two-by-four inch boards and string.

What if?

•       What if the second premise was true.  Would this lead to the conclusion that they were created by extraterrestrials?  Not necessarily – Natural forces could be at work here.  Unusual wind patterns or other natural phenomena could be at work here. 

•       No logical explanation or sound support for the claim of extraterrestrial creation of crop circles.

Compehensiveness

•       Claims to knowledge must account for all of the pertinent data and not just chosen bite and pieces of information.

•       Our textbook looks at the myth of an unusually large number of births following a blackout on the East Coast in 1965. 

•       Most people attribute the increase to nothing else to do but have sex when we have no other entertainment.

•       But there was a unusual number of births nine months later.  What else could account for it?

Births and Black Outs

•       Data was correct but the rise in birthrate happens every Monday and Tuesday as it did nine months after the black out.  Why?

•       Doctors prefer not to work on weekends.  Because of this many Doctors will induce labor or do Caesarian sections on Monday and Tuesday.

•       This tends to be a boring fact so the Blackout story is widely talked about and believed.

•       Original reason is not true and other data needed to be incorporated to find out the real reason.

•       Whenever a claim cannot or does not take into account all of the relevant evidence, it fails the comprehensiveness test.