In formal logic, an argument with a contradictory conclusion is not valid. In mathematical logic, **an argument with a contradictory conclusion will be declared valid if the premises are themselves contradictory**. This also why we know that mathematical logic is junk, and not any logic at all.

Contents

## Does a contradiction make an argument invalid?

In the corresponding truth table there is a row where the hypothesis are all true and the conclusion false, therefore the argument is invalid. But there is also a row where the conditions are true and the conclusion is true. **This is not, then, a contradiction, but it is invalid.**

## Can a valid argument have a false conclusion example?

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**. In these examples, bad luck rather than bad logic led to the false conclusion.

## Why is an argument with two contradictory premises always valid?

Well, if the premises are contradictory, then **they cannot all be true (that’s just what contradictory means) so they can’t all be true while the conclusion is false** (the necessary condition for non-validity). So the argument cannot be non-valid, it must be valid. Thus an argument with contradictory premises is valid.

## What is a contradictory argument?

Contradictory premises involve **an argument (generally considered a logical fallacy) that draws a conclusion from inconsistent or incompatible premises**. Essentially, a proposition is contradictory when it asserts and denies the same thing.

## Does every valid argument have a true conclusion?

**All valid arguments have all true premises and true conclusions**. All sound arguments are valid arguments. If an argument is valid, then it must have at least one true premise.

## What is a tautological argument?

A tautological argument is otherwise known as a circular argument, that is, **one that begins by assuming the very thing that is meant to be proven by the argument itself**.

## What do you call an argument that contradicts itself?

**A paradox** is a logical puzzle that seems to contradict itself.

## Is fallacy and contradiction same?

The contradiction is just the opposite of tautology. When a compound statement formed by two simple given statements by performing some logical operations on them, gives the false value only is called a contradiction or in different terms, it is called a fallacy.

## Can a valid argument have all false premises?

An invalid deductive argument can have all false premises and a true conclusion. 5. **A valid deductive argument cannot have all false premises and a true conclusion**.

## What makes an argument valid?

An argument is valid **if the premises and conclusion are related to each other in the right way** so that if the premises were true, then the conclusion would have to be true as well.

## Can a valid argument have false premises and a false conclusion?

**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.

## How do you know if an argument is valid or invalid?

To judge if each is valid or invalid, ask the question, “If the premises are true, would we be locked in to accepting the conclusion?” **If the answer is “yes,” then the argument is valid.** **If the answer is “no,” then the argument is invalid.**

## What makes some conclusions true but invalid?

As well as arguments that have true premises/conclusion but are invalid, we can have arguments that are valid and have a true conclusion but are unsound because **a premise is untrue**. Here, P1 can be true, C follows from the Ps (validity), C can be true, but the argument is unsound because P2 is false.

## What is an example of an invalid argument?

An argument is said to be an invalid argument if its conclusion can be false when its hypothesis is true. An example of an invalid argument is the following: “**If it is raining, then the streets are wet.** **The streets are wet.**

## What is a valid but unsound argument?

An argument is valid if and only if it is impossible for its. premises to be true, while its conclusion is false. So one way for an argument to be bad is for it to be invalid; another way for it to be bad is for it to be valid, but unsound (i.e., **for it to be valid but have one or more false premises**).

## What is a deductively valid argument?

An argument is deductively valid if, and only if, it’s not possible for it to be the case that both, 1) all of its premises are true and 2) it’s conclusion is false, as it were, at the same time. This will be our official definition of deductive validity.

## What is invalid syllogism?

A valid syllogism is one in which the conclu- sion must be true when each of the two premises is true; an invalid syllogism is **one in which the conclusions must be false when each of the two premises is true**; a neither valid nor invalid syllogism is one in which the conclusion either can be true or can be false when …

## Can an argument be invalid and unsound?

An unsound argument is the opposite of a sound argument. Thus, **an unsound argument can be either valid or invalid**. However, if the argument is valid, it has at least one false premise in order to consider it as an unsound argument.

## Can an inconsistent argument be valid?

**Yes.** **An argument with inconsistent premises is valid, regardless of what the conclusion is**. If an argument has inconsistent premises, then it is impossible for all the premises to be true at the same time; hence it is impossible for all the premises to be true while the conclusion is false.

## What are logical fallacies in an argument?

Logical fallacies are **arguments that may sound convincing, but are based on faulty logic and are therefore invalid**. They may result from innocent errors in reasoning, or be used deliberately to mislead others. Taking logical fallacies at face value can lead you to make poor decisions based on unsound arguments.

## 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.

## 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**.

## What logical conclusion can you draw about an argument that is valid but has a false conclusion?

A valid argument had false premises must have a false conclusion,it is impossible that ones have false premises and a true conclusion. What logical conclusion can you draw about an argument that is valid but has a false conclusion? **This argument must have at lease one false premise**.