5. Because nothing exists, nothing also does not exist. If you look at nothing as the opposite of something. The existence of one requires the existence of the other. But since one explicitly says it is nothing i.e. does not exist. That should also mean that something also does not exists. Or nothing exists. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.