cause and effect

For the longest time, we were taught that when something happens, it will cause something else. Without the cause there can be no effect. When you get a cut, you bleed; when you snap your fingers, you get a sound. Even though this is true, there may not always be the same effect from one cause. I may get sick 100 times after eating a certain food, but on that 100 first time, I could be perfectly fine. There is never a certainty as to what can happen from a cause, but it is certain that there will be an effect.