Depending on breed, management and environment, the domestic horse (including draft horses) today has a life expectancy of 25 to 35 years. It is uncommon, but a few animals live into their 40s and, occasionally, beyond. The oldest verifiable record was Old Billy, a 19th-century horse that lived to the age of 62.
TRUE. Validity is a necessary condition for being sound. 14. FALSE. A valid argument can have a true conclusion and false premises (see #11); and if an argument does not have all true premises, then it is not sound.
An argument is valid if and only if the truth of its premises entails the truth of its conclusion and each step, sub-argument, or logical operation in the argument is valid. Under such conditions it would be self-contradictory to affirm the premises and deny the conclusion.