A consequence argument (Finch and Warfield’s modification of van Inwagen’s argument)

Let F be any truth.  Let P be a complete description of the world in the distant past.  Let L be the laws of nature.  Let Np be the claim that “p and no one has, or ever had, any choice about whether p.”

1. (Premise) Necessarily(P&L à F).
2. (Premise) N(P&L).
3. (Premise) If Np and Necessarily(p à q), then Nq.
4. NF. (By 1-3)

A Frankfurt-style response

1. (Premise) In a grand Frankfurt case where (a) one is the only person in existence, and (b) the neurosurgeon is a deterministically functioning non-person robot not made by a person and watching over one’s whole life, one will be responsible for a fact F even though no one has, or ever had, any choice about whether F.
2. (Premise) Such a Frankfurt case is possible.
3. Therefore, it is possible that both NF and someone is responsible for F.

Pereboom’s four-case argument

First, consider the following cases:

(i) Every aspect of Plum’s life is controlled by neuroscientists, who make him kill Ms. White out of a rational egoism they implanted.

(ii) The neuroscientists have programmed Plum to weigh reasons for action in such a way that he is causally determined to decide, in a rationally egoistic way, on the basis of these reasons, to kill Ms. White, though he does not always act in rationally egoistical ways.

(iii) Plum gets his methods of weighing reasons for action through a rigorous upbringing that makes him often, but not always, rationally egoistic, in such a way that he is causally determined to kill Ms. White.

(iv) Plum grows up in a normal way in a deterministic world, where he is rationally egoistic, and he is causally determined to kill Ms. White on the basis of his egoistical reasons.

The argument now is:

1. (Premise) If Plum does not freely kill Ms. White in case (i), he does not freely kill her in case (ii).
2. (Premise) If Plum does not freely kill Ms. White in case (ii), he does not freely kill her in case (iii)
3. (Premise) If Plum does not freely kill Ms. White in case (iii), he does not freely kill her in case (iv).
4. (Premise) If compatibilism holds, Plum freely kills Ms. White in case (iv).
5. (Premise) Plum does not freely kill Ms. White in case (i).
6. Therefore, compatibilism is false.

Mele’s response

• In cases (i) and (ii), Plum is not able, in the compatibilistic sense of “able”, to sufficiently affect how he weighs desires.
• In case (iv) and maybe case (iii), Plum is able, in the compatibilistic sense of “able”, to sufficiently affect how he weighs desires.
• Freedom depends on whether one is able, in the compatibilistic sense, to sufficiently affect how one weighs desires.
• Therefore, the compatibilist can say that there is freedom in case (iv) but not in (i) and (ii).