Section 1: Evaluating Arguments and Evidence (Critical Thinking: Reason and Evidence - D265)

Unsound argument

a deductive argument that is invalid, has one or more false premises, or both

Premise

a proposition supporting or helping to support a conclusion.

Inductive argument

are meant to provide probable support for their conclusions, and good inductive arguments are said to be both strong and cogent.

Inductive arguments include

arguments from analogy, qualified authority, casual inferences, scientific hypothetical reasoning, extrapolations from samples and so on.

Premise Indicators

because, since, for, for example, for the reason that, in that, given that, as indicated by, due to, owing to, this can be seen from, we know this by, supposing that, assuming that, as.

All true premises + strong inductive support = ?

cogent argument

Abduction

drawing a conclusion based on the explanation that best explain a state of events, rather than from evidence proved by the premises.

If an argument has any __________ ______________ then it is unsound.

false premises

Complex Propositions

have internal logical structure, meaning they are composed of simple propositions. Whether they are true or false depends on whether their parts are true or false and how those parts are connected.

Soundness

is both about structure and truth: you must have good structure and true premises to make a sound argument.

Deductive arguments include:

mathematical arguments like proofs, logical arguments, arguments from definition and so forth.

Deductive argument

meant to provide decisive support for their conclusions, and good deductive arguments are said to be both valid and sound.

All arguments are composed of _________ and _________, which are both types of statements.

premises and conclusions.

Bad argument

premises do not support the conclusion.

Good argument

premises support the conclusion.

Inductive arguments are supposed to make their conclusions ________________.

probable

If the conclusion doesn't follow from the premises an argument can't be __________, even if all the premises are true.

sound

Propositions

statements that can be true or false.

Conclusion

the claim that the whole argument is intended to support, demonstrate or prove.

Conclusion Indicators

thus, therefore, hence, consequently, as a result, so, accordingly, clearly, must be that, shows that, we must/may conclude that, it follows that, for this reason, ergot, entails that, wherefore.

A weak inductive argument is automatically ____________.

uncogent

Induction

using past experience to make future predictions.

(Inductive arguments) ___________ and ___________ are the words we use in place of "sound" and "unsound".

"cogent" and "uncogent"

We call an inductive argument ____________ when it fails to demonstrate the the conclusion is likely to be true, even assuming the truth of the premises.

"weak"

Arguments can go wrong in two ways

1. Bad inferential structure 2. False premise

Validity

A property of an argument structure. If the premises of any argument with this structure are true then the conclusion of that argument must be true.

Truth

A property of propositions. That is, only propositions can be true or false.

Words used to identify independent propositions

AND, OR, EITHER, BUT, IF, THEN.

Non-Propositions

Are not statements about matters of fact. They do not make a claim that can be true or false.

Premises

Claims, evidence, and ideas intended to support the conclusion. If the assumptions are true, and the argument has a good inferential structure, then the conclusion either must be or is likely to be true as well.

True or False: an explanation is an argument, so is a story, series of disconnected statements, or any set of statements that do not contain inferential connection.

False.

True or False: Arguments can be true or false.

False. (Arguments can NEVER be true or false. Only propositions.)

True or False: We CANNOT recognize conclusions and premises by identifying certain words being used.

False. (Indicators are used to spot a conclusion or a premise.)

True or False: If an inductive argument is strong, we don't need to ask if it's cogent or uncogent.

False. (We still need to ask.)

Simple Propositions

Have no internal logic structure, meaning whether they are true or false does not depend on whether a part of them is true or false. They are simply true or false on their own. (Example: Harry Potter wears glasses. The sky is blue.)

Socratic Method

Learning through a dialectic exchange of ideas, rather than a passive transmission of information.

Critical Thinking

Primarily the ability to think carefully about thinking and reasoning -- to criticize your own reasoning.

Inductive reasoning

Relies on the predictability of nature to reveal that the future is likely to resemble the past.

false premise

Something wrong with their particular content.

Bad inferential structure

The premises do NOT in fact, demonstrate or maybe even support the conclusion. We can accept the premises as true without being logically compelled to accept the conclusion.

True or False: (deductive arguments) It's possible for the premises to be true but the conclusion is false.

True.

True or False: A sentence and a proposition are not the same thing.

True.

True or False: A statement and a proposition are the same thing.

True.

True or False: All sound arguments are valid, but not all valid arguments are sound.

True.

True or False: Premises are are supposed to be statements that, if you accept they are true, give you reason to believe that the conclusion is also true.

True.

True or false: Inductive = Ampliative

True.