Frankfurt (1969) on Alternate Possibilities

 It is misleading to say that the aim of Frankfurt (1969) is to disprove the principle of alternate possibilities when he explicitly says that he is defending a revised version of the principle, according to which  “…a person is not morally responsible for what he has done if he did it because he could not have done otherwise…” (Frankfurt 1969: 838)

He does say that “the principle of alternate possibilities is false” and argues against the claim that “… a person is morally responsible for what he has done only if he could have done otherwise…” which he calls the (traditional?) principle of alternate possibilities (Frankfurt 1969: 829) But he does defend the view that a person is morally responsible for what he has done only if he has not done it because he could not have done otherwise, which is also a version of the principle of alternate possibilities. He even starts his article by asserting that “…no one … seems inclined to deny or even to question that the principle of alternate possibilities (construed in some way or other) is true.” (Frankfurt 1969: 829) I take it that the reason he explicitly mentions “construed in some way or other” is because he thinks there is (at least) one construction of the principle (his) on which it is true.

    Frankfurt’s position in 1969 is not very different from Sartorio. He also thinks that what is important is not so much whether there are alternate possibility but what “impels”, “moves”, “leads” one to act or play any role “…in bringing it about that he does what he does”. (Frankfurt 1969: 830) He just does not identify this later property with anything causal.

    On the other hand, he explicitly mentions that his examples aim at pumping our “moral intuitions” against the principle (Frankfurt 1969: 830), while also mentioning that his discussion will be “in more general terms”. (Frankfurt 1969: 830) However, I think the right way to interpret the examples are as intuition pumps, not directly of its conclusion, but mostly of its premises.

In my reconstruction, the argument has two big premises. One is more philosophically substantial and the other is more factual, more psychological. This second one, he states very explicitly: “there may be circumstances that constitute sufficient conditions for a certain action to be performed by someone … but that do not actually impel the person to act or in any way produce [their] action.” The first one is the former principle that it is only what makes someone do what they do what matters. 

With these two premises in place, the argument follows very smoothly:

1. Premise 1. Given an action A, let there be an occurring circumstance C such that C necessitates A, but does not make A.
2. Premise 2. Whether A is free or not depends exclusively on what makes A.
3. From (1), A’s agent could not have done otherwise (from the occurrence of C and the definition of necessitation).
4. From (1), given C, there must be a different factor F that makes A. [Actually, there is an extra premise here, i.e., that it is possible for something that makes a behavior happen when it is already necessary (and made necessary by something else)]
5. From (2), if A is free, there must be something in F that makes A free.
6. From (4) and (5), C and F are compatible, i.e., it is possible for F to make A even if C is present and necessitates A.
7.  From (1), (3), (5) and (6), A is a free action, even if its agent could not have done otherwise, as long as its agent did not do it because they had no choice.

So, the relevant question is, therefore, where do the premises come from. On a first moment, I thought that the first premise could be argued for as a particular case of a more general and well-known metaphysical principle, i.e., that making is more (and most likely less) than mere necessitation. This means that it is possible for an event or state of the world C to metaphysically entail another one E without C making (i.e., being neither the ground nor the cause of or reason why, etc.) E. Frankfurt’s first premise is just this general principle applied to behavior. However, my colleague Luis Estrada made me notice that Frankfurt's argument requires something stronger that necessitation. As is costumarily defined, P necessitates Q iff it is necessary that P implies Q. However, in order for (3) to follow from (1), it is necessary that from C follows not A, but that A is somehow necessary in the sense that A's agent could not have done otherwise. Thus, C cannot just imply A, but has to imply the necessity of A. The sort of implication involved can be as weak as necessary as long as it supports Modus Ponens.

If not from a more general metaphysical principle, then where could he premise come from? I am now under the impression that it is the role of the examples to make this first premise intuitive. After all, it is a claim of possibility and it is customary to take it that if thought experimens are good for anything in philosophy, it is for showing that something is (conceptually or metaphysically) possible. In other words, the reason why so many philosophers have accepted the genuine possibility of a necessary action being guided by a different factor than that one that makes it necessary is precisely because frabkfurt gave us examples where this seems to be the case. However, this also opens them up for straightforward criticism, i.e., there is a huge gap between something being coherently describable and it being genuinely possible.

References

• Barceló, Axel (2015) “What makes quantified truths true?”, en Alessandro Torza (ed.) Quantifiers, quantifiers, quantifiers, Synthese Library, ISBN 978-3-319-18361-9, 355-373. https://doi.org/10.1007/978-3-319-18362-6_15 
• Batens, Diderik (2008) "On possibilities and thought experiments." Rescher Studies. A Collection of Essays on the Philosophical Work of Nicholas Rescher, edited by Robert Almeder, Berlin, Boston: De Gruyter, 29-58. https://doi.org/10.1515/9783110329094.29: 29-57.
• Cain, James (2003) "Frankfurt Style Cases", Southwest Philosophy Review 19: 221–9. 
• Chalmers, David (2002) "Does conceivability entail possibility?" Conceivability and possibility, 145–200.
• Frankfurt, Harry G. (1969) "Alternate possibilities and moral responsibility", Journal of Philosophy 66: 829-39.