What is a valid argument？ 什么是有效论证.docxVIP

What is a valid(符合逻辑的) argument?An argument is a set of statements aimed at explanation and/or persuasion. It consists of a conclusion/claim and premises (i.e., reasons) that support the conclusion. In formal logic, a valid argument is one in which the arguments conclusion must be true if the supporting premises are in fact true.Truth and ValidityWhether an argument is valid does not speak to the truth, or falsity, of an arguments conclusion or its premises. Validity refers simply to whether the conclusion flows logically from the premises. Thus, an argument may contain false premises and a false conclusion and still be valid.Determining ValidityTo determine whether an argument is valid, you must answer the following question: Assuming the premises are true, is another conclusion possible? If so, the argument is invalid.Soundness and ValidityA sound argument is a valid argument with true premises. Therefore, a sound argument must be a valid argument.ExamplesExamples of valid arguments are as follows:Premise: All dogs are mammals.Premise: My pet Sam is a dog.?Conclusion: Therefore, Sam must be a mammal.Premise: All banks are financial institutions.Premise: Wells Fargo is a financial institution.Conclusion: Wells Fargo is a bank.?Examples of invalid arguments follow:Premise: Only men have blue eyes.Premise: Christina has blue eyes.Conclusion: Therefore, Christina must be a man.?Premise: All Toyotas have 4-wheel drive.?Premise: My car is a 4-wheel drive car.Conclusion: Therefore, my car is a Toyota.ConsiderationsValidity is a term used to describe deductive(推论的)arguments as opposed to inductive(?归纳的)arguments. A deductive argument aims for a conclusion that must be true given true premises, whereas an inductive argument claims a highly probable conclusion, given true premises. Therefore, deductive arguments are either valid or invalid; there is no such thing as almost valid. Inductive arguments, however, fall on a spectrum(范围) from strong to weak.Source:A Concise Intro