Phil 140

Critical Thinking

using logic to determine whether or not we ought to believe the various things we read, or people tell us

Logic

the discipline that evaluates arguments, methods to determine whether the arguments are good or bad

Argument

a group of statements, the premises, are claimed to provide support for the conclusion

Premises

statements that present reasons or evidence

Conclusion

the statement that presents reasons or evidence

Statements

sentences used to make claims about how things are

Examples of Non-Statements

questions, commands, promises

Types of Arguments

Inductive and Deductive

Inductive Arguments

incorporate the claim that it is improbable that the conclusion is false given that the premises are true

start with a specific observation to form a general probably conclusion

seeks probability based on evidence

Deductive Arguments

incorporate the claim that it is impossible for the conclusion to be false if the premises are true

start with a general premise to reach a guarded, guaranteed conclusion

deductive reasoning leads to a certain conclusion

Criteria for identifying arguments

presence of indicator terminology

the strength of the inferential connection

Indicator terminology

In - probable, improbable, plausible, implausible, likely, unlikely

De - necessarily, certainly, absolutely, definitely

Always look for these first, easily definable

inferential connections

the logical relationship between ideas, if they support each other

In - if the premises do not guarantee the conclusion; if the premises are not both true than they only make the conclusion probably true

De - premises guarantee the conclusion, both premises are true

forced to look for this if there are no indicator words

Evaluating Deductive arguments

Validity - the relationship between premises and conclusion; the argument is valid if and only if its not possible for the premises to be true and the conclusion false

Soundness - does the argument make sense

ex) valid but unsound - All pigs have wings, and all things with wings can fly. It follows that all pigs can fly.

Evaluating Indictive arguments

Strength - in a strong inductive argument, it is improbable that the conclusion is false given that the premises are true; instead of validity; the premises may have strong points but still don’t confirm the conclusion

what classifies an argument

a passage is only an argument when it contains at least one premise, a conclusion, and includes and inferential claim

Indicator Term for all arguments

premise - because, since, given that

conclusion - hence, therefore, it follows that

inferential claim/relations and controversial conclusions

inferential relations - one or more of the statements in fact provide adequate reasons or evidence for one of the others

evidence that the conclusion could be probable, conclusion may be hidden in the passage

controversial conclusions - is this the kind of thing someone would be giving an argument for

Non-Arguments - types of unstructured passages

statement of belief - a passage whose point is to convey the speaker’s opinions about something; I believe

loosely associated statements - a collection of statements on the same general subject; statements are not super connected

report - a groups of statements that convey information about some topic or event, tightly connected, same topic

conditional statement - a statement of the form : if…. then,

• antecedent - statement after if

• consequent - statement after then

three types of Structured Passages

1. expository

2. illustrative

3. explanatory

Expository passage

a collection of statements that begins with a topic sentence followed by one or more sentences that develop or elaborate on it

illustrative passage

a collection of statements consisting of a generalization together with one or more instances of this generalization

piece of writing that supports a general statement or main idea by providing specific examples, details, comparisons, or anecdotes to clarify and make the idea more understandable and relatable to the reader

explanatory passage

a group of statements that claim to shed light on some event or phenomenon

• explanandum - the statement that describes the event

• explanans - statements that do the explaining

restructuring an argument

• locate indicators - determine if its an argument

• list premises (P1, P2) and conclusion (C)

• write them in separate declarative statements

• eliminate all indicators and omit statements that are neither a premise or conclusion