A deductive argument is invalid if:
Its premises are true but its conclusion is false
Validity in deductive logic is a property of the form of an argument, not of the truth of the statements in it, so the answer depends on the precise definition.
A deductive argument is valid when it is impossible for the premises to be true and the conclusion false at the same time - that is, when true premises guarantee a true conclusion. It follows immediately that an argument is invalid exactly when its premises are true but its conclusion is false, since that is the one combination validity forbids. This is option (2).
The other combinations are all consistent with validity, which is the point that makes the question testing. An argument with all false premises and a false conclusion may be perfectly valid: from all cats are birds and all birds are fish, it follows validly that all cats are fish, though every statement is false. An argument with false premises and a true conclusion may also be valid. And an argument with true premises and a true conclusion is certainly not invalid on that account.
The distinction worth keeping is between validity, which concerns whether the conclusion follows, and soundness, which requires the argument to be valid and its premises actually true.
Hence a deductive argument is invalid if its premises are true but its conclusion is false.
Similar Questions
The product of any three consecutive integers is divisible by 6. Therefore, 3×4×5 (=60), is divisible by 6? Which type of reasoning is embodied here?
Given below are some characteristics of reasoning. Select the code that states a characteristic which is not of deductive reasoning:
In which of the following arguments 'the relation that exists between premises and conclusion is that of logical necessity'?
The argument which claims that its conclusion is conclusively supported by its premises is called
Which is an example of a correct deductive argument?
“The relation that exists between Premises and Conclusion is that of logical necessity” – is a case with which of the following arguments ?
In a valid deductive argument, if the premises are true, then:
Which one of the following can be validly inferred from the proposition - “All animals are wild”?
When the conclusion of an argument follows from its premises necessarily, the argument is called:
Given below are two statements:
Statement I: No immediate inference can ever be drawn from only one premise.
Statement II: In Aristotelian syllogism, the conclusion is drawn from the first premise through the mediation of the second.
In light of the above statements, choose the correct answer from the options given below:
Important Questions from Deductive
The product of any three consecutive integers is divisible by 6. Therefore, 3×4×5 (=60), is divisible by 6? Which type of reasoning is embodied here?
Given below are some characteristics of reasoning. Select the code that states a characteristic which is not of deductive reasoning:
In which of the following arguments 'the relation that exists between premises and conclusion is that of logical necessity'?
The argument which claims that its conclusion is conclusively supported by its premises is called
Which is an example of a correct deductive argument?
