This is not related to my exchange

Ok, so you know how heat doesn’t rise, cool air sinks? That doesn’t make any sense because there is not such thing as cold, there is only the absence of heat. And so heat really does rise, doesn’t it? But then what’s pushing it up? The less hot air? Less hot air sinks? Why is it sinking? Because the hotter air is rising? I have no idea how anything works and if that’s actually true, this is the worst paradox ever and I think about it a lot.