It's impossible to prove a negative, as I'm sure you're well aware.
So the media accounts saying that the Taliban or al-Qaida had nukes in Afghanistan are not capable of being disproved.
The fact that they weren't used is pretty good evidence. The fact that no evidence was discovered that they ever had them is another.
So, your turn. Is any statement you hear presumptively true unless you can absolutely disprove it?
Your brain is made of cheese. Please elucidate how exactly you know this to be untrue.
You got me on that one. It is a Swiss/Cheddar/Muenster mix that I will NEVER disclose.