 Imagine you are driving a car through town, and you come to a fork in the road. You turn left, but no one was forcing you to go one way or the other. Next you come to a crossroads. You turn right, but no one was preventing you from going left or straight on. There is no traffic to speak of and there are no diversions or police roadblocks. So you seem, as a driver, to be completely free. But this picture of your situation might change quite dramatically if we consider that the reason you went left and then right is that you’re addicted to cigarettes and you’re desperate to get to the tobacconists before it closes. Rather than driving, you feel you are being driven, as your urge to smoke leads you uncontrollably to turn the wheel first to the left and then to the right. Moreover, you’re perfectly aware that your turning right at the crossroads means you’ll probably miss a train that was to take you to an appointment you care about very much. You long to be free of this irrational desire that is not only threatening your longevity but is also stopping you right now from doing what you think you ought to be doing.