4 Acceptability of Premises
- Observation
- a priori
- testimony
- if premise is acceptable, sub-argument is acceptable
7 Unacceptability of Premises
- Observation
- Testimony
- a priori
- weak sub-conclusion
- problems in language (vague, ambiguity, euphemism, loaded laguage, equivocation)
- contradicting (inconsistency between premises)
- begging the question
a priori statement
statement that can be true or false on the basis of logic and reasoning alone.
- can derive from reason alone.
ex: all square has four sides.
ex: no one can steal his own property.
Testimony
based on personal experience or knowledge of others. We can believe their testimony is true unless:
- the claim is implausible:
- The person lacks credibility:
- The claim goes beyond what the person could possibly know from their own experience and competence:
Observation
e
Common Knowledge
statement which is known by most people. varies from culture, time, place etc.
What does “a priori” mean in Latin
“from the first”. Knowable before experience.
contrasting term of “a priori”
a posteriori. means “from something that is posterior, or afterward”. Another word for “a posteriori” is “empirical”
false Testimony: Implausibility of claims
claim is too bizarre and crazy to even believe.
ex: I ate peanut butter and lost 40 pounds in 2 weeks.
false Testimony: Unreliability of Person or Source
- person is known to lie or deliberately deceive.
2. person has a flaw in them. (hearing problem, can’t rely on them for telling you how a singing concert went)
false Testimony: Failure to Claim to Experience and Competence
Can’t rely on someone saying “This mcdonald’s is the best in the world.” because clearly she hasn’t visited every mcdonalds in the world.
