Every smoker knows how harmful it is. All smokers are well aware of the risks of lung cancer, emphysema. kidney cancer, throat cancer, etc. No amount of logic or discussions will make a smoker stop. A smoker will not stop until he/she is ready. Thats just how addiction works.
P.S. As I type this, I am lighting a cigarette after quitting for 2 yrs, then 8 weeks then 6weeks. All while knowing my favorite Aunt is battling lung cancer. ughhhhh