WEEK 2 - Argument Analysis Flashcards
what is an argument ?
an argument is a set of statements, one of which (the conclusion) is suppose to be supported by the others (the premises)
how to look for arguments by words:
- since
- firstly, secondly,
- for, as, after all
- assuming that, in view of the fact that
- follows from, as shown/indicated by
- may be inferred/deduced/derived from
conclusions are often proceeded by words like :
- therefore, so, it follows that
- hence, consequently
- suggests /proves /demonstrates
- entails, implies
what is standard form ?
a way of presenting the argument which makes clear which statements are premises, how many premises there are, and which statements is the conclusion
in presenting an argument in the standard format, the premises and the conclusion are:
clearly identified
what is validity ?
one desirable feature of arguments is that the conclusion should follow from the premises
what if we have an argument with more than one premise ?
although the two premises of this argument are false, this is actually a valid argument
what to ask yourself while evaluating validity ?
ask yourself whether it is possible to come up with a situation where all the premises are true and the conclusion is false
can the argument be invalid even if the conclusion and the premises are all actually true ?
yes
is it possible for a valid argument to have a true conclusion even when all its premises are false ?
yes
the following describes what;
- the purpose is to provide reason fro accepting conclusion
- understanding arguments is important because it helps us evaluate whether there is in fact reason to believe a conclusion
arguments (give reason for belief)
what are arguments composed of ?
statements
what are statements ?
are sentences or parts of sentences that assert that something is the case
what are the three types of sentences ?
- statements
- interrogative sentences
- imperative sentences
what are statments ?
sentences that are used to make assertion
what are interrogative sentences ?
sentences that ask a question
what are imperative sentences ?
sentences that issue a command
“Is Spot a good dog?” is an example of what type of sentence
Interrogative sentences
“be a good dog, Spot!” is an example of what type of sentence ?
Imperative sentences
how do we test for being a statement ?
try appending “is it true that” or if “is it true that” is grammatically correct
what are some premise indicators that indicate a premise ?
- because since, for, after all
- first, second, etc
- on the assumption that, assuming that
- in view of the fact that
- this follows from
- this is shown/ indicated/ suggested / supported by
- this can/ may be inferred/ deduced/ derived from
what are some conclusion indicators that indicate a conclusion ?
- therefore, so , thus, hence, consequently, in consequence
- It follows that
- this suggests / proves / demonstrated / entails / implies / shows that
- as a result
how to put an argument in standard from ?
- number and display each premise on a separate line
- display the conclusion on the last line
- remove all premise indicators
- remove all indicators or replace them with a simple conclusion indicator like “therefore”
when is an argument valid ?
if and only if it is logically impossible for the premises to be true while the conclusion is false
if the truth of the premises guarantees the truth of the conclusion what does the mean for the argument ?
argument is valid
if premises are correct and therefore conclusion is correct than the argument must be …
valid
if an argument is not valid it is …
invalid
when is an argument sound ?
an argument is sound when it is valid and all the premises are true
what does the soundness of an argument require both of ?
that it be valid and that its premises be true
must a sound argument have a true conclusion ?
yes
what are the properties of arguments for validity ?
truth
what are the properties of arguments for soundness ?
falsity
what is the formula for modus ponens ?
If P then Q. P. Therefore, Q.
what is the formula for affirming the consequent ?
If P then Q. Q. Therefore, P.
what is the formula for modus tollens ?
If P then Q. Not-Q. Therefore, not-P.
what is the formula for denying the antecedent ?
If P then Q, not-P. Therefore, not-Q.
what is the formula for hypothetical syllogism ?
If P then Q, If Q then R. Therefore, if P then R.
what is the formula for disjunctive syllogism?
P or Q. Not-P. Therefore, Q. ; P or Q. Not-Q. Therefore, P.
what is the formula for dilemma ?
P or Q. If P then R. If Q then R. Therefore, R.
when is an arguent valid ?
an argument is valid if and only if it is logically impossible for the premises to be true while the conclusion is false
when is an argument sound ?
when it is valid an all its premises are true
what is an invalidating counterexamples ?
is a logically possible scenario in which the premises are true and the conclusion is false
(P1) All good teachers can use Zoom.
(P2) Prof. Z can use Zoom.
(P3) Prof. Z is a good teacher.
is an example of what?
an invalidating counterpart
The moon is made of cheese.
The sun is made of tofu.
Therefore, the moon is made of cheese.
is an example of what ?
circularity
what is a tautology ?
a necessarily true statement
if P, then Q.
Not- Q.
Therefore, not-P.
is an example of what ?
modus tollens
if P, then Q.
if Q, then R
Therefore, if P, then R
is an example of what ?
hypothetical syllogism
P or Q.
Not-P.
Therefore, Q.
P or Q.
Not-Q.
Therefore, P.
is an example of what ?
Disjunctive Syllogism
(P1) if it’s an acid, the test strip will turn red
(P2) if is not the case that the test strip will turn red
(C) therefore, it’s not the case that it’s an acid
is an example what ?
modus tollens
(P1) If Ron eats one chip, then he will eat the whole bag.
(P2) If Ron eats the whole bag, then he will end up extremely thirsty.
(C) Therefore, if Ron eats one chip, he will end up
extremely thirsty.
is an example of what ?
Hypothetical syllogism
(P1) Either Rico is taller than Maariyah or Maariyah is taller than Rico.
(P2) It is not the case that Rico is taller than Maariyah.
(C) Therefore, Maariyah is taller than Rico.
is an example of what ?
Disjunctive Syllogism
P or Q.
if P, then R
if Q, then S
Therefore, R or S
is an example of what ?
Dilemma
(P1) Either Myron wins or Nia wins.
(P2) If Myron wins, unemployment rates will rise.
(P3) If Nia wins, inflation will get out of control.
(C) Therefore, either unemployment rates will rise or inflation will get out of control.
is an example of what ?
dilemma
is denying the antecedent a valid argument from ?
no
if P, then Q.
not-P.
Therefore, not Q
is an example of what ?
denying the antecedent
(P1) If Bryan studies hard, Bryan will pass Critical Thinking. (TRUE)
(P2) Bryan does not study hard (TRUE)
(C) Therefore, Bryan will not pass Critical Thinking. (FALSE)
is an example of what ?
denying the antecedent
what is a circular argument ?
where the conclusion is also a premise
why are arguments with necessarily true conclusions valid ?
an argument with a necessarily true conclusion, there is no possible way for the premises to be true and the conclusion false
what is counterintuitive consequence 1 ?
circular arguments are valid
what is conterintuitive consequence 2 ?
arguments with necessarily true conclusions are valid
what are counterintuitive consequence 3?
arguments with inconsistent premises are valid
