10. EXPLANATION

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SCIENTIFIC REASONING:Not just for doing “science”!

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It’s night, and Bob is at home doing homework. His roommate went out with friends a few hours ago, and Bob is alone. He’s startled to hear the bedroom door slam. He gets up and looks around. All the windows are closed, and there is no wind.

“I wonder if there’s a ghost in the house”, he thinks. Then it occurs to him that his roommate may have come home and could be trying to scare Bob as a prank. “That makes more sense – my roommate jokes around a lot, and a ghost seems unlikely. How would a ghost that passes through solid walls be able to push a door closed?”

Bob realizes that if his roommate is hiding in the house, his roommate’s shoes will probably be in the closet at the back door. Bob goes and checks the closet, but his roommate’s shoes aren’t there. “Hm, this is weird. Maybe it’s not my roommate, after all. Still, it’s hard to believe there’s a ghost…” 3

What is Bob’s observation?

What is his first hypothesis?

What is his alternative hypothesis?

Which does he think is the better explanation? Why?

Which does he test?

What is his prediction?

He observes that the prediction is true | false, and this confirms | disconfirms the hypothesis.

The clock says 12:46.

The best explanation of this is that it’s 12:46.

It’s 12:46.

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Disjunction of all the weird ideas

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Hypothesis 3

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Observation: Lyle is late for class.

Hypothesis 1: _______ ( %)

Non-competing hypothesis: ________

Hypothesis 2: _______ ( %)

Hypothesis 3: ______ ( <1%)

UPDATING PROBABILITIES

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Hypothesis 4

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1) Imagine some new information that would change the probabilities.

2) Suggest a new hypothesis and adjust the probabilities.

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Hypothesis 1: _______ ( %)

Hypothesis 2: _______ ( %)

Hypothesis 3: ______ ( <1%)

[Hypothesis 4: _______ ( %)]

JUDGING COMPETING EXPLANATIONS

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Which explanation is simpler?

Observation: Lyle is running down the hall with his beard on fire.

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Hypothesis #1: He fell asleep in the instructors’

room and a group of students who were angry

about their midterm marks snuck up and set his

beard on fire, and then the sink in the

bathroom was broken so he couldn’t get water.

Hypothesis #2: He set his beard on fire for fun.

Which explanation fits better with your background beliefs?

Observation: Lyle is running down the hall with his beard on fire.

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Hypothesis #1: He fell asleep in the instructors’

room and a group of students who were angry

about their midterm marks snuck up and set

his beard on fire, and then the sink in the

bathroom was broken so he couldn’t get water.

Hypothesis #2: He set his beard on fire for fun.

OFTEN:EVIDENCE = REPORT/MEASUREMENT/ETC.

“I scored ten goals!”

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“Balance: $5,000,000”

!

Reconstruct as an extended IBE argument.Flight MH370 changed course several times and then flew

out to the middle of the Indian ocean without sending any

messages ①. So the pilot must have gone crazy ②. This is

way simpler than all the plane’s communication and

guidance gear malfunctioning at once and in a way that

would cause multiple course changes ③. And it fits better

with our knowledge of terrorists ④, since terrorists would

have crashed the plane into something on land or at least

claimed responsibility for the attack afterwards ⑤.

Write and number the implicit statement.

State the observation and the hypothesis.

State two alternative hypotheses.

Put in standard form and diagram.

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Think of a possible (or actual) observation.Suggest an explanatory hypothesis and one alternative hypothesis, and

construct an extended IBE argument in standard form:Main Argument +

Optional:

Subargument 2

[Background belief]

Subargument 1

[Hypothesis] is simpler than [Alternative

Hypothesis].

[Hypothesis] fits better with background

beliefs than [Alternative Hypothesis].

[Hypothesis] is the best explanation of

[Observation].14

Pickone