Is willpower a myth or a strange power that we possess? Well only you can answer that question. There are many people who have been able to stop smoking on sheer willpower alone, however these people tend to experience very harsh cravings and withdrawal symptoms and often end up relapsing.
Willpower is basically a decision. It is when you decide to do something against your own beliefs and also decide that you do not want to do it. The fact remains that you are actually only changing an opinion that you hold in your mind so for those who strongly believe in willpower being some sort of magic or voodoo, it is most certainly not!
Some believe that willpower is inner strength that we can call upon at any given time to help us do something against our own true will. Although this could be considered true, it is most likely not an inner strength and more like a change of heart or change of decision that we affirm to ourselves.
When using willpower you are creating a stressful situation for yourself. And I encourage you to ask yourself the following question... do you need more stress in your life? Especially when you are giving up smoking cannabis?? I'm sure you would agree that stress is something that none of us need in our lives. Stress is also a trigger to smoke! So when we use willpower we create more stress and more passion to smoke.
I think you agree that willpower is not a valid option to use to give up smoking marijuana, and it is also a huge contributor to why most people relapse.