what determines whether an argument is valid?
Hence the argument is valid. To tell whether an argument is valid, figure out what the form of the argument is, and then try to think of some other argument of that same form and having true premises but a false conclusion. If you succeed, then every argument of that form must be invalid. A valid form of argument can never lead you from true premises to a false conclusion. For instance, consider the argument: 1  If Socrates was a philosopher, then he wasn't a historian.