Hume makes what strikes me as two separate claims regarding when it is appropriate for us to hold someone morally accountable for their actions. The first is when the action is caused by something “in the character and disposition of the person who performed them” (EHU 8.29). The reason is that the character of the individual is “durable and constant” (Ibid.). If this is not the case then we cannot blame or praise the individual because the action is not caused by something lasting in them.
Hume also remarks that we do not blame or praise individuals when their actions are done in haste and without deliberation. He writes,
Men are not blamed for such actions, as they perform and casually, whatever may be the consequences. Why? but because the principles of these actions are only momentary, and terminate in them alone. Men are less blamed for such actions as they perform hastily and unpremeditately, than for such as proceed from deliberation (8.30).
Here too the contrast is between something that is constant and something that is temporary. However, it is not immediately clear that deliberating about an action is tied directly to possessing a particular character. I wonder what (or maybe, if there is a) relation Hume intends there to be between character and the act of deliberating.
It could be that deliberation is a necessary condition on actions for which we hold the agent morally responsible. If one never deliberated, then there would be no consistent motive which caused the action. The mere act of deliberating provides an opportunity for one’s character to cause the action rather than a fleeting passion. However, this threatens to weaken the notion of a character being durable motive of an agent’s actions. If the agent’s character requires the agent to deliberate then in what sense is it something which reliably causes the agent’s action? It seems more appropriate to attribute the consistency to the agents ability to think about and act in accordance with a particular motivation. But this seems to run contrary to Hume’s claim that reason requires motivation to cause an action. In the Treatise he writes that “reason alone can never be a motive to any action of the will” (188.8.131.52). I take this to imply that passion is explanatorily prior to deliberation. But if in the absence of deliberation one’s character is unreliable in causing actions, then it appears that deliberation is explanatorily prior.
It may be that there is an important distinction between reason being the cause of an action and the act of deliberation that makes the second option unproblematic. Or perhaps the notion of character is more closely tied to that of character than deliberation simply being a necessary condition for character to cause an action.