Originally Posted by

**emakarov**

In real life, we do assume that "if P, then Q" is true when P is false. For example, the US Constitution says that being at least 35 years old is a necessary condition to become a US president. In other words, for every person x, if x is the president of the US, then x is at least 35 years old. This is a true statement. (I don't know if there were any exceptions in the past, but let's ignore that.) Now take any person x who is not 35 years old; then the premise of the statement above is false, yet the full statement continues to be true.