Hume’s view is similar to Hobbes’s. For instance, their titles are identical.
Hume defined the liberty of action as “a power of acting or not acting, according to the determinations of the will; that is, if we choose to remain at rest, we may; if we choose to move, we also may” (§8, par. 23). Hobbes defined it as “the absence of all the impediments to action that are not contained in the nature and intrinsical quality of the agent” and added that “a free agent is he that can do if he will and forbear if he will” (pp. 38, 29).
Those of you who tune in regularly know that Hume disputed Hobbes’s attempt to show that everything must have a cause. But in the end he wound up with pretty much the same position, since he denied that anything happens by chance and defined chance as the absence of cause (§8, par. 25). Since human actions are one kind of event along with the movement of billiard balls, they have causes too. As Voltaire put it, “it would be very singular that all nature, all the planets, should obey eternal laws, and that there should be a little animal five foot high, who, in contempt of these laws, could act as he pleases, solely according to his caprice” (The Ignorant Philosopher, p. 23 [ECCO]).
Hume added two things to what Hobbes had said. Well, three, if you count that inimitable writing style.
First, he did more to make the case for thinking that human behavior is caused. Hobbes’s official argument relies on a very general claim, namely, that everything has a cause and all causes make their effects necessary.
Hume argued that we appeal to causes in understanding human behavior. We explain why people behave the way they do by giving their motives for behaving that way. (We also have to add something about their beliefs, namely, that they believe that acting in a particular way is a good way of achieving what they want to achieve. But let’s not worry about that right now).
Second, Hume added an argument that moral responsibility could not exist without causal determination. Rewards and punishments make no sense if the will is completely free from causal determination for two reasons: first, they wouldn’t work if people didn’t reliably respond to them, second, they would not make any sense if the agent responsible for the decision to act “perished” along with the action rather than persisting as a person’s character traits do. (§8, par 28-9).
Let me elaborate on the second point for a moment. Hume’s ethical theory primarily concerns character: we assess people as good or bad depending on what their general motivations are like. Those who are motivated to do things that are immediately agreeable or useful are regarded as virtuous or good while those who are motivated to do things that are immediately disagreeable or harmful are regarded as vicious or bad. Of course, even well-meaning people can do things that turn out badly. Hume’s thought was that we only blame the person with bad or negligent motivations, not the one who means and behaves well but has things turn out badly.
Hume thought that if everyone is free to act apart from his or her motivations, none of this would make any sense, and so he insisted that causal determination of behavior is necessary for morality.
Bramhall, by contrast, argued that it is pointless and unfair to punish people for what they cannot help doing. From his perspective, which is shared by most of us, at least in theory, no one can be responsible for doing X unless it was genuinely possible to have not done X.