Try this experiment some time. It was shown to me in medical school.
Take a brand new box of pristine sticks of chalk - you know - the kind your teachers always used on a blackboard in school. Open the top and be sure all of the pieces of chalk are in one piece but do not remove them from the box. Close the top of the box again.
Now, hold the box of chalk really high over a solid concrete surface (a tile floor usually works well, too).
Now, drop the box and observe it hitting the floor.
Open the box and examine the contents. No doubt you will find many, many shattered sticks of chalk. But almost as certainly, there will be one or two sticks that are still pristine, whole pieces of chalk that survived the fall.
Now why would this have been shown to our medical school class?
Because the speaker was explaining how to counteract this excuse posed to doctors when they attempt to ask a patient to stop moking: "But my mother smoked all her life and she never got cancer!" Statistically, you see, some survive even after they were subjected to the risks of smoking. Just like some pieces of chalk survive when their box is dropped to the floor.
So when I read that Phillip Morris wants to produce a "reduced risk" cigarette or new tobacco products with a "reduced risk" of cancer, I can't help but think that their efforts will be just like dropping a box of chalk from a little lower altitude, hoping that a few more sticks of chalk will survive.
Wouldn't it be better not to drop the box at all?