In order to know anyone’s motives and character we require inference, from their actions to their motives and character (T 2.1.11.3; 3.3.1.7/317, 576). Without knowledge of anyone’s character no sentiment of approbation or blame would be aroused in us. Without inferences moving in this direction – from action to character (as opposed to from character to actions) – no one would be an object of praise or blame and, hence, no one would be regarded as morally responsible. In these circumstances, praising and blaming would be psychologically impossible. Along the same lines, external violence, like liberty of indifference, also makes it impossible to regard someone as an object of praise or blame. When an action is produced by causes external to the agent we are led away from the agent’s character. Clearly, then, actions that are either uncaused or caused by external factors cannot render an agent responsible, not because it would be unreasonable to hold the person responsible, but rather because it would be psychologically impossible to hold the person responsible, where this stance is understood in terms of the operation of the moral sentiments. It is in this way that Hume brings his observations concerning the operation of the indirect passions to bear on his claim that necessity is essential to morality and, in particular, to our attitudes and practices associated with responsibility and punishment.