Phil 105 Critical Thinking: Chapter 5 - Entailment Cont.

EVIDENCE

facts about the world that support some claim or hypothesis

EVIDENCE TEST

1. How likely is F given that H?

2. How likely is F given that not H?

First rule of evidence:

Any observation of F that passes this test should increase our confidence in the claim or hypothesis H

STRENGTH TEST

Involves a comparison:

Suppose H is true. How likely is F? Quantify. 

Suppose H is false. How likely is F? Quantify.

Compare these 2 quantities.

DEGREES OF CONFIDENCE

Confidence in a claim can be expressed on a spectrum ranging from 0 to 1

• 0 = certain that claim is false

• 0.5 = equal confidence in claim being true or false

• 1 = certain that claim is true

also can be translated into percentage

NOT probability

• restricted to future events

• a statistical generalization about classes of events

IS probability

the probability of a claim is simply your degree of confidence in that claim

STRENGTH FACTOR (SF)

How much more likely the evidence is given that the claim or hypothesis is true than given that it is false

SF= How likely the evidence is given H divided by how likely the evidence is given not-H

The higher the number, the more support the evidence proides for the claim or hypothesis

OPPOSITE EVIDENCE RULE

If E is evidence for H then not-E is evidence for not-H

SURVIVOR BIAS

occurs when researchers focus on individuals, groups, or cases that have passed some sort of selection process while ignoring those who did not

ATTRITION BIAS

a type of selection bias due to systematic differences between study groups in the number and the way participants are lost from a study

MEDIA BIAS

Media is more motivated not by truth but by engaging contentent

ECHO CHAMBER

phenomenon where our sources of information are selected to support our opinions which creates a loop as the views become more polarizing

Social media compounds the problem