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.
Sound argument. a valid argument in which all of the premises are true. Unsound argument. one that either is invalid or has at least one false premise.
Valid arguments may have: True premises, true conclusion. False premises, false conclusion. False premises, true conclusion.
TRUE: If an argument is sound, then it is valid and has all true premises. Since it is valid, the argument is such that if all the premises are true, then the conclusion must be true. A sound argument really does have all true premises so it does actually follow that its conclusion must be true.
A valid argument is one in which the truth of the premises guarantees a truthful conclusion. A valid argument can have false premises, while a sound argument must have true premises, and therefore, a truthful conclusion.
This course addresses these questions with the help of a standard textbook in classical logic. Fulfills Foundations - Mathematical Sciences. Offered fall and winter semesters.
In effect, an argument is valid if the truth of the premises logically guarantees the truth of the conclusion. The following argument is valid, because it is impossible for the premises to be true and the conclusion nevertheless to be false: Elizabeth owns either a Honda or a Saturn. Elizabeth does not own a Honda.
Judge the reasoning and not the content (true or false statements). Think hypothetically. Ask, "IF the premises are true, are we locked into the conclusion?" If yes, then the argument is valid. If no, then the argument is invalid.
The definition of valid is something effective, legally binding or able to withstand objection. An example of valid is a driver's license that hasn't expired. An example of valid is someone giving evidence that proves an argument.
A sound argument is both valid and has all true premises. Since a sound argument is valid, it is such that if all the premises are true then the conclusion must be true. Since a sound argument also has all true premises, it follows that a sound argument must have a true conclusion.
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.
Remember the key to judging deductive arguments to be valid or invalid is not whether the premises are true or false. Rather, the question is what are the premises saying and what are they not saying, and whether if they were true would the conclusion be true. If the answer is yes, then the argument is valid.