I agree, you cannot say for sure that spirits do not communicate using clocks or whatever. However, what you can say is whether a certain number comes up more than chance. If it does, then that is evidence that something is manipulating it. To make sure that you yourself are not responsible though, you will need another device to check the clock for you. For example, if I get hungry at around 11:11, and go to sleep around 11:11, then I would be responsible for seeing 11:11 on the clock, because that is when I am likely to check the time. I cannot say that spirits or anything else is responsible until I remove my own behavior from the equation.