FALSE:
A valid argument must have a true conclusion only if all of the premises are true
. So it is possible for a valid argument to have a false conclusion as long as at least one premise is false. 2. A sound argument must have a true conclusion.
What is an example of a valid argument with a false conclusion?
If Elizabeth Taylor is president of the United States, then Elizabeth Taylor must be younger than 35. Elizabeth Taylor is president of the United States. So, Elizabeth Taylor must be younger than 35. For either example,
the logic is valid but the premises are false
.
Is an argument with false premises and a true conclusion valid?
For either example, the logic is valid but the
premises are false
. … Validity is a guarantee of a true conclusion when the premises are true but offers no guarantee when the premises are false. False premises can lead to either a true or a false conclusion even in a valid argument.
Can a valid argument have a false conclusion quizlet?
Can a valid argument have a false conclusion?
Yes
—if at least one of the premises is false.
How can an argument be valid but untrue?
A deductive argument is said to be valid
if and only if it takes a form that makes it impossible for the premises to be true and the conclusion
nevertheless to be false. … In effect, an argument is valid if the truth of the premises logically guarantees the truth of the conclusion.
Can a false argument be valid?
A valid argument can have false premises
; and it can have a false conclusion. But if a valid argument has all true premises, then it must have a true conclusion. … Since a sound argument is valid, it is such that if all the premises are true then the conclusion must be true.
What is an argument with false premises and false conclusion?
So, an argument with a
mixture of true and false premises
is still considered to be an argument with false premises–it is false that all of the premises are true. Nevertheless, in these examples, the conclusion is false. For either example, the logic is invalid and the premises are false. Here the conclusion is false.
Are all arguments with true conclusions valid?
All valid arguments have all true premises and true conclusions
. … If an argument is valid, then it must have at least one true premise.
Can an argument be almost valid?
Some arguments, while not completely valid, are almost valid
. 10. A strong argument may have true premises and a probably false conclusion. … If an argument has true premises and a true conclusion, we know that it is a perfectly good argument.
What is an example of an invalid argument?
An argument can be invalid
even if the conclusion and the premises are all actually true
. To give you another example, here is another invalid argument with a true premise and a true conclusion : “Paris is the capital of France. So Rome is the capital of Italy.” .
Can an argument be true or false quizlet?
A valid argument can have false premises and a true conclusion
. If an argument is unsound, then it must have false premises. An argument may be unsound in one of three ways. (1) It may be valid with false premises.
Can a sound argument be invalid?
Question originally answered: Can a sound argument be invalid?
No, it cannot
. A sound argument is defined as a valid argument, with the extra property that the premises of the argument are true.
Can inductive arguments have false conclusions?
To summarize, a
strong inductive argument is
one where it is improbable for the conclusion to be false, given that the premises are true. A weak inductive argument is one where the conclusion probably would not follow from the premises, if they were true.
How do you determine if an argument is valid?
Work out the truth-values of premises and conclusion on each row. Check to see if there are any rows on
which all of the premises are true
and the conclusion false (counterexamples). If there are any counterexample rows, the argument is formally invalid. If there are none, it’s formally valid.
Which of the following combinations can a valid argument never have?
The only combination that you will not find in a valid argument is: a.
true premises and a false conclusion
.
Why is it an argument should be true correct and valid?
Validity: An argument is
valid when, IF all of it’s premises were true, then the conclusion would also HAVE to be true
. In other words, a “valid” argument is one where the conclusion necessarily follows from the premises. It is IMPOSSIBLE for the conclusion to be false if the premises are true.
What is false conclusion?
n. 1. ( Logic) a purported refutation of a proposition that
does not in fact prove it false
but merely establishes a related but strictly irrelevant proposition. 2. ( Logic) the fallacy of arguing in this way.
Can an argument with false premises be invalid?
Invalidity is a no guarantee of a true conclusion when the premises are false.
False premises can lead to either a true or a false conclusion
in an invalid argument. In these examples, luck rather than logic led to the true conclusion.
Does an argument provide a good reason for believing its conclusion if it is valid?
For a deductive argument to provide one with a good reason for believing its conclusion,
it has to be valid and have true premises
. An argument that is both valid and has all true premises is called a sound argument. Valid arguments need not have true conclusions. But sound arguments must have true conclusions.
Is an argument with Dependant premises always valid?
No, a
logically valid argument is valid
because the conclusion is a logical consequence of the premises. It doesn’t matter if the premises happen in fact to be true or not. The argument itself is valid in any case.
Can inductive arguments be valid?
Inductive
arguments are not usually said to be “valid”
or “invalid,” but according to the degree of support which the premises do provide for the conclusion, they may be said to be “strong” or “weak” over a spectrum of varying degrees of likelihood.
Is it possible to have an argument that is strong but Uncogent?
For an argument to be cogent, the premises must be true. Thus, since strength does not guarantee true premises, it also does not guarantee cogency. Consequently, it is
possible
to have an argument that is strong but uncogent. … But it is possible that the conclusion still could be true even if the premises were false.
Do all valid arguments have at least one false premise?
All valid arguments have at least one false premise
. An argument is a set of statements where some of the statements, called the premises, are intended to support another, called the conclusion. … If a valid argument has only false premises, then it must have a false conclusion.
Are all persuasive arguments valid?
No, not all persuasive arguments are valid
. “To persuade someone of something is to influence her opinion by any number of means, including emotional appeals, linguistic or rhetorical tricks, deception, threats, propaganda, and more. Reasoned argument does not necessarily play any part at all in persuasion” (50).
What is an example of false premise?
A false premise is an incorrect proposition that forms the basis of an argument or syllogism. … For example, consider this syllogism, which involves a false premise:
If the streets are wet, it has rained recently
. (premise)
How do you determine if an argument is valid or invalid?
Valid: an argument is valid if and only if it is necessary that if all of the premises are true, then the conclusion is true; if all the premises are true, then the conclusion must be true; it is impossible that all the premises are true and the conclusion is false. Invalid: an argument that is not valid.
Which of the following is not a valid argument?
Answer: Valid: an argument is valid if and only if it is necessary that if all of the premises are true, then the conclusion is true; if all the premises are true, then the conclusion must be true; it is impossible that all the premises are true and the conclusion is false.
Invalid
: an argument that is not valid.
Can an invalid argument be strong?
An invalid argument is always unsound
. An argument is sound if it is valid and the premises are all actually true. What do we know about the conclusion if an argument is valid and the premises are all true? That the conclusion is true, of course.
What are the three important valid argument forms?
- Modus Ponens. If P then Q. P. …
- Modus Tollens. If P then Q. not Q. …
- Disjunctive Syllogism. P or Q. …
- Hypothetical Syllogism. If P then Q. …
- Barbara Syllogism. All A’s are B’s. …
- Reductio ad Absurdum. P. …
- Replacement. a is an F. …
- Proof by Cases. P or Q.
Do all weak arguments have false conclusions?
A weak argument must have a false conclusion
. Some inferential claims are false. Deductive arguments with all true premises are sound. If an argument is valid and has false premises, then the conclusion cannot be true.
How do you prove invalid?
An argument is invalid
if the conclusion doesn’t follow necessarily from the premises
. Whether or not the premises are actually true is irrelevant. So is whether or not the conclusion is true. The only question that matters is this: Is it possible for the premises to be true and the conclusion false?
How many conclusions can an argument have?
A conclusion is a statement in an argument that indicates of what the arguer is trying to convince the reader/listener. What is the argument trying to prove? There can be only
one conclusion in a single argument
.
What is Uncogent argument?
A cogent argument is an inductive argument that is both strong and all of its premises are true. An uncogent argument is
an inductive argument that is either weak or has at least one false premise
.
Can a valid argument be strong?
Definition: A strong argument is a
non-deductive argument that succeeds in providing probable
, but not conclusive, logical support for its conclusion. A weak argument is a non-deductive argument that fails to provide probable support for its conclusion.
Can a statement be true or false?
A statement is true if what it asserts is the case
, and it is false if what it asserts is not the case. For instance, the statement “The trains are always late” is only true if what it describes is the case, i.e., if it is actually the case that the trains are always late.
Can a valid deductive argument ever have false premises Why or why not quizlet?
No, it’s not possible
. A deductively valid argument is such that if the premises are true , its conclusion must be absolutely, positively be true.
Why is sound argument defined as valid?
Sound Arguments
It’s
trying to establish conclusive support for its conclusion
. Secondly, the argument is valid: the premises, if true, would guarantee that the conclusion is also true. And on top of all that, the premises are actually true. Therefore, a sound argument guarantees that its conclusion is true.
Is argument form valid?
The final statement is called the conclusion. An
argument form is valid if
, no matter what particular statements are substituted for the statement variables in its premises, whenever the resulting premises are all true, the conclusion is also true. … An argument is valid means that its form is valid.
What is the difference between valid arguments and fallacious arguments?
An argument is valid
if the conclusion must be true whenever the premises
are true. In other words, an argument is valid if the truth of its premises guarantees the truth of its conclusion. … An argument that is not valid is invalid or fallacious. If an argument is valid and its premises are true, the argument is sound.
