What is distinctive of torture is not just the infliction of intense pain (however that is to be understood), but the experience of a kind of forced passivity in a context of urgent need, a context in which such passivity is experienced as a kind of open-ended exposure, vulnerability, and impotence. In order to make sense of the difficult cases above, we need to consider not just the intensity of pain that might be inflicted upon someone, but the alienation of the victim from his own bodily and emotional life that forced passivity before pain and fear can engender.
For torture to occur, its perpetrators and victims must see themselves as standing in a particular kind of relationship with one another, and understand that the other understands this as well. Characteristically, victims of torture see themselves as being completely at the mercy of their tormentors. A victim of torture must be unable to shield herself in any significant way, and must be unable to effectively evade or fight back against her tormenter. I may intentionally inflict great pain in a fight in order to make my foe do something; I may gouge his eyes in order to get him to stop choking me. Nevertheless, insofar as my opponent is not helpless before me, my eye-gouging is not an instance of torture, even though I am forcing him to comply with my desires by inflicting pain. Police who use tear-gas to disperse a crowd are not engaging in torture, regardless of how painful the gas may be. In these cases, the victims still have it within their power to resist or mitigate the violence done to them: by retreating, devising ways of protecting themselves, or countering their assailants with new threats of their own. In contrast, the torture victim realizes that he has no room to maneuver against his antagonist, no way to fight back or protect himself, and he must realize that his antagonist operates in an awareness of this as well.
(David Sussman, "Defining Torture," Case Western Reserve Journal of International Law 37 [2005]: 225-30, at 227 [footnote omitted])
Note from KBJ: Two things. First, torture has to be bad (like chemotherapy) in order for it to work. If it weren't bad, it wouldn't work, and innocent lives would be lost. Second, it is always within the power of the person being tortured to make it stop. Simply tell the interrogators what they want to know.