## Friday, August 22, 2014

### A criticism of some consequence arguments

The standard consequence argument for incompatibilism makes use of the operator Np which abbreviates "p and no one has or has ever had a choice about whether p". Abbreviating the second conjunct as N*p, we have Np equivalent to "p and N*p". The argument then makes use of a transfer principle, like:

• beta-2: If Np and p entails q, then Nq.
When I think about beta-2, it seems quite intuitive. The way I tend to think about it is this: "Well, if I have no choice about p, and p entails q, then how can I have a choice about q?" But this line of reasoning commits me not just to beta-2, but to the stronger principle:
• beta-2*: If N*p and p entails q, then N*q.
But beta-2* is simply false. For instance, let p be any necessary falsehood. Then clearly N*p. But if p is a necessary falsehood, then p entails q for every q, and so we conclude—without any assumptions about determinism, freedom and the like—that no one has a choice about anything. And that's unacceptable.

This may be what Mike Almeida is getting at in this interesting discussion which inspired this post.

Of course, this counterexample to beta-2* is not a counterexample to beta-2, since although we have N*p, we do not have Np, as we do not have p. But if the intuition driving one to beta-2 commits one also to beta-2*, then that undercuts the intuitive justification for beta-2. And that's a problem. One might still say: "Well, yes, we have a counterexample to beta-2*. But beta-2 captures most of the intuitive content of beta-2*, and is not subject to this counterexample." But I think such arguments are not very strong.

This is not, however, a problem if instead of accepting beta-2 on the basis of sheer intuition, one accepts it because it provably follows from a reasonable counterfactual rendering of the N*p operator.

Mark said...

I would like to examine the relation between the counter-example to beta-1 and Np.

Beta-1: [Np&N(p-->q]-->Nq.

Beta-1 (along with rule alpha) uncontroversially implies agglomeration.

Agglomeration: (Np&Nq)-->N(p&q).

My question is: given the definition of Np as "p and no one has a choice about whether p", is agglomeration invalid?

The counter-example to agglomeration about tossing an indeterministic coin is what has convinced most people that agglomeration is invalid.

I'll post the counter-example here. From "Incompatibilism Proved":

"But agglomeration is invalid. Suppose you actually won’t toss an indeterministic
coin but can. Let p be the proposition that the coin won’t land heads. Let q be
the proposition that the coin won’t land tails. Then N p, since p is true and you
have no choice about p, because there is nothing you could do to make p false—you
can’t make the coin land heads. Similarly, Nq. On the other hand N(p ∧ q) is false,
because you do have a choice about p ∧ q—if you toss the coin, the conjunction
p ∧ q will be false, since the coin will land either heads or tails."

But it strikes me that something is wrong here. It seems to me that given Np (and not N*p), the counter-example doesn't work.

Here's the tension between two propositions of the excerpt I quoted from your article:

(1) "Let p be the proposition that the coin won’t land heads."

AND

(2) "Then N p, since p is true and you

AND

(3) "Let q be
the proposition that the coin won’t land tails".

AND

(4) "Similarly, Nq".

(4) is equivalent to (5):

(5) "Then N q, since q is true and you

(5) and (2) make two explicit assumptions, namely:

(6) p is true, and q is true.

From (6), and (1), and (3), we get:

(7) "the coin won’t land heads" & "the coin won’t land tails".

The following is true:

(8) If the coin won't land heads, then it lands tails.

From (7) and (8), we get:

(9) "the coin lands tails" & "the coin won't land tails".

(9) is a contradiction (the landings of the coin are happening at the same time).

I believe the counter-example to agglomeration was based on N*p and not Np. Perhaps that's why the counter example began with "Suppose you actually won’t toss an indeterministic
coin but can."

-WH

Mark said...

Minor Correction:

I retract this statement:

"Here's the tension between two propositions of the excerpt I quoted from your article:"

And replace it with:

"Here's the tension I found in the excerpt I quoted from your article:"

Alexander R Pruss said...

(8) is false. If the coin won't land tails AND it is tossed, then it will land heads.

Mark said...
This comment has been removed by the author.
finney said...

How would you rate this argument?

1. If I am able to do X, then I am able to do what is necessary to do X, including preventing some Y which would prevent X (sufficient and necessary causal conditions).
2. If I am unable to do X, then I am not morally responsible for failing to do X (widely shared assumption among libertarians and compatibilists).
3. If I am unable to prevent Y, then I am not morally responsible for failing to do X (implication from 1 and 2).
4. I am unable to prevent God from decreeing Y. (Assertion).
5. So, I am not morally responsible for failing to do X.

Alexander R Pruss said...

I think 1 is false. I am able to go for a bike ride on the river trail, but I am not able to prevent the city from closing the river trail, even though their closing the river trail would prevent my bike ride on it.

Of course IF the city were to close the river trail, I wouldn't be able to go for a bike ride on it any more.

finney said...

I’m wondering how to revise premise 1 to account for that scenario. I think when I say “prevent,” I mean specifically preventing an event which WOULD otherwise occur. Wouldn’t that fix things?

finney said...

Actually, that might not work. How about:

If I am able to do X, then for any Y which would prevent X, either (a) I am able to prevent Y from occurring, or (b) Y does not occur for some other reason.

Alexander R Pruss said...

You have to change some other premises to make the argument valid then.

finney said...

1. If I am able to do X, then for any Y which would prevent X, either (a) I am able to prevent Y from occurring, or (b) Y does not occur for some other reason.

2. If I am unable to do X, then I am not morally responsible for failing to do X.

3. If I am unable to prevent Y and Y occurs, then I am not morally responsible for failing to do X (implication from 1 and 2).

4. I am unable to prevent God from decreeing Y.

5. God decrees Y.

6. So, I’m unable to prevent Y (based on a deterministic assumption about God’s decree).

7. So, I am unable to do X.

8. So, I am not morally responsible for failing to do X.