Williams on External Reasons

(Copied from some recent work, feedback welcome.)

We can divide reasons into two kinds. First, there are internal reasons, which are reasons that could motivate the agent if the agent merely deliberated correctly from their current motivational set. Second, there are external reasons, which are all reasons that are not internal (i.e. all reasons that could not motivate the agent if the agent merely deliberated correctly from their current motivational set). Williams famously argued that there are no external reasons. On the face of it, this looks implausible. The entire point of normative criticism, one might say, is that it operates independently of what people are motivated to do. Williams allows this only in the weak sense that some deliberation is possible, but he still must maintain that people who are malevolent enough have no reason to be motivated otherwise. This seems implausible. So Williams must have strong arguments for his position. He produces two.

His first argument is this (1997:367, 1993:38-9):
1) If an agent has a reason to do something, then it must be possible for them to act for that reason.
2) If it is possible for an agent to act for a reason, then they must be able to be motivated to act for that reason.
3) If an agent is able to be motivated to act for a reason, then they must be able to acquire that motivation merely by deliberating on their current motivational set.
4) Therefore: If an agent has a reason to do something, then they must be able to acquire a motivation to do that thing by deliberating on their current motivational set.

What might we say about this? I think that there is an equivocation between premises (1) and (2). Why?

Premise (1) states that if an agent has a reason to do something, then it must be possible for them to act for that reason. Premise (2) states that if it is possible for an agent to act for a reason, then they must be able to be motivated to act for that reason. The equivocation occurs in the term "possible". Premise (1) is plausible only in a very broad sense of possible. In accepting it, we are merely accepting the claim that reasons should be the right kinds of thing to motivate agents. But premise (2) uses a much narrower sense of possible, according to which something is possible only if it is motivationally possible given the agent’s current motivations and some set of deliberative rules. We have been given no reason to accept this narrower sense of possible, and my brief remark above about the nature of normative criticism seems to count heavily against it. That is, premise (1) is only plausible on a very broad sense of possible, and premise (2) is only true on a very narrow sense of possible. So either one premise is false and the argument is unsound, or if both premises are true there is an equivocation, and the argument is invalid.