Lol. I always wondered the same. When I was about 3 years old, my dad would always go up to me and tell me I'm doing nothing. I was completely confused by this statement. I was probably doing more work in my head then anything else. So technically it wasn't nothing. Technically, it was something more...The first one is very true. The second one is not. You are something. 🙂
The third one? Hmmmmm... That's tough. Technically you can not do nothing, you're always breathing, your heart is always beating, your mind is always working. However, by social terms, you can definitely be doing nothing. Although I guess you did post this, so that's not nothing. Ugh! Grammarly keeps trying to correct "that's not nothing" and "Technically you can not do nothing" for me. I have to keep dismissing it!