Can arguments with contradictory premises be 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.
Can an argument with a contradictory conclusion be valid?
Yes, an argument with contradictory premises is deductively valid. That’s because it’s impossible to have all its premises true and its conclusion false (since its premises can never all be true)*.
Are self contradictory statements valid?
Given a set of contradictory (or self-contradictory) premises, it is never the case that the premises are all true — because for one to be true (“the moon is blue”), another must be false (“the moon is not blue”). Thus, any such argument is valid on this definition of validity.
Why is contradictory premises unreliable?
Because when the premises of an argument contradict each other, there can be no argument. If there is an irresistible force, there can be no immovable object. If there is an immovable object, there can be no irresistible force. Get it?’
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.
What kind of paradox is self contradicting?
It is shown that the basic examples of paradoxes, the liar paradox and Russell’s paradox, are self-contradictory. Self-contradiction is not only a structure of paradoxes but is found also in proofs using self-reference.
Can a valid argument have all false premises?
A valid argument can have all false premises and a true conclusion.
Are contradictions false?
; a proposition is a contradiction if false can be derived from it, using the rules of the logic. It is a proposition that is unconditionally false (i.e., a self-contradictory proposition).
What are the 3 types of paradoxes?
Three types of paradoxes
- Falsidical – Logic based on a falsehood.
- Veridical – Truthful.
- Antinomy – A contradiction, real or apparent, between two principles or conclusions, both of which seem equally justified.
What is oxymoron and paradox?
An oxymoron is a self-contradicting word or group of words (as in Shakespeare’s line from Romeo and Juliet, “Why, then, O brawling love! O loving hate!”). A paradox is a statement or argument that seems to be contradictory or to go against common sense, but that is yet perhaps still true—for example, “less is more.”
What is a paradoxical statement?
A paradox is a statement, proposition, or situation that seems illogical, absurd or self-contradictory, but which, upon further scrutiny, may be logical or true — or at least contain an element of truth. Paradoxes often express ironies and incongruities and attempt to reconcile seemingly opposing ideas.
What makes a valid argument?
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.
What are examples of contradictions?
Here are some simple examples of contradictions.
- I love you and I don’t love you.
- Butch is married to Barb but Barb is not married to Butch.
- I know I promised to show up today, but I don’t see why I should come if I don’t feel like it.
- The restaurant opens at five o’clock and it begins serving between four and nine.
Can a simple contradiction be an argument?
First: terminology. An argument is a collection of statements (more details below) while a tautology or contradiction is a single statement. So with regard to your last question, it makes no sense to say that “an argument is equivalent to a contradiction” – they are different kinds of objects.
How do you prove a statement by contradiction?
We follow these steps when using proof by contradiction:
- Assume your statement to be false.
- Proceed as you would with a direct proof.
- Come across a contradiction.
- State that because of the contradiction, it can’t be the case that the statement is false, so it must be true.
What follows from a contradiction logic?
That is, once a contradiction has been asserted, any proposition (including their negations) can be inferred from it; this is known as deductive explosion. The proof of this principle was first given by 12th-century French philosopher William of Soissons.
Why is a contradiction always false?
“Contradiction” and “always false” mean the same thing, logically speaking, as do “tautology” and “always true.” is true. So proving that something is a contradiction constitutes a proof that its negation is true, because the negation of a contradiction—i.e. the negation of something that is false—is always true.