Huh?
Sure you can. Maybe in this case it would be difficult, but "you can't prove a negative" is not a true generalization.
Suppose someone said, "Prove that Barack Obama has NOT stayed in Illinois his entire life." Could you prove it? Of course...just show a single example where he is outside Illinois.
Sure you can. Maybe in this case it would be difficult, but "you can't prove a negative" is not a true generalization.
Suppose someone said, "Prove that Barack Obama has NOT stayed in Illinois his entire life." Could you prove it? Of course...just show a single example where he is outside Illinois.
No, you can't possibly prove that McCain hasn't pressured the media. How would you possibly do that? By contacting and getting statements from every news organization that reported the story? Your example is not a negative because, just as you have pointed out, it would obviously be very easy to prove Obama had "stayed" outside of Illinois. Now, if the original poster said to his liberal friend, "prove that McCain pressured the media," that is provable if the evidence is there.
In other words, you can't present evidence to prove something that never happened.