PHL 214 Chapter Notes - Chapter 7: New Zealand National Rugby Union Team, False Dilemma, Contraposition
Document Summary
One statement deductively entails another if and only if it is impossible for the second one to be false, given that the first one is true. The nature of the impossibility is logical impossibility. Another way to think of this is to say that an argument is deductively when it is impossible for all the premises to be true and the conclusion false. This means that deductively valid arguments satisfy the r and g conditions of arg. Many argument are valid based on their logical form. When evaluating deductively valid argument we need to realize that the argument will satisfy the r and g conditions, but may fail to satisfy the a condition of acceptable premises. Sometimes arguments are valid not because of their form, but because of the mean of the word involved. Robert is a brother logically entails that robert is male. This is because of the meaning of brother.
