Chapter 3: Clarity Flashcards
Logic
the study of the connection between the premises and conclusions
Suppositional Strength
the strength of the connection between premises and conclusions
Good Arguments Need:
i) true premises
ii) suppositional strength
Implicit Premises
claims that are left unstated and taken for granted
Deduction
The process of drawing conclusions from premises that entail them
e.g. All dogs have ears; golden retrievers are dogs, therefore they have ears.
Induction
When premises support conclusion but do not entail them
e.g. Nala is an orange cat and she purrs loudly; every orange cat I’ve met purrs loudly. All orange cats purr loudly.
Common Tradeoff
Deductive arguments: Maximal suppositional strength but harder to establish premises
Inductive arguments: weaker suppositional strength but more plausible premises
Ground Floor Beliefs
supports that do not require further support
i) directly perceptual beliefs
ii) self-evident beliefs
Directly Perceptual Beliefs
beliefs supported directly by perception
Self-Evident Beliefs
beliefs that are so obviously true, that finding support for them seems absurd
e.g. 1 + 1 = 2, green is a colour
Standard Form
a particular way to express arguments
Two Key Features:
1) premises and conclusions are labelled
2) conclusions are labelled to indicate which premises support them, and whether that support is inductive or deductive
Example of Standard Form
P1. If it’s morning, then the direction of the sun is east.
P2. It’s morning.
C1. The direction of the sun is east. (from P1 and P2 by deduction)
P3. We should be going east.
C2. We should be going in the direction of the sun. (from C1 and P3 by deduction)
(C1. is an “interim conclusion”)
Principle of Charity
find the best version of the argument the speaker could plausibly have intended
Ambiguity
when two sentences with different meanings share the same written and spoken form
The Forms of Ambiguity
1) Lexical ambiguity
2) Bare plurals
3) Syntactic ambiguity