Part 1: John was a heavy smoker. John died prematurely. In an autopsy, it was determined that the cause of John's death was lung cancer and that the cause of the lung cancer was his heavy smoking. Was John's smoking the cause of his death?
Part 2: It turns out that there was a contract out on John's life and that a murderer would have killed him the next day after he died from lung cancer. That is, if John had not died prematurely due to the smoking, he still would have died prematurely. Was John's smoking still the cause of his dying prematurely?