I’ve been asked to comment on Peter van Inwagen’s objection to theological determinism. This is, of course, bound up with his case for libertarian freedom. If LFW is true, then theological determinism is false.
I’ll confine myself to three comments:
i) Van Inwagen’s argument has evolved over the years. In fact, he’s come to the point at which he regards the arguments for determinism and indeterminism as equiprobable, or—if you prefer--equi-improbable, in the sense that both can’t be right, although both can both be wrong, and he is, in his own words, “absolutely clueless,” as to where the truth lies, and, indeed, regards the dilemma as “evidently impossible of solution.”
ii) This raises the question of what, if anything, would count as evidence for LFW even if LFW were true. There are three logical alternatives:
a) Hard determinism: We are not free to do otherwise even if we wanted to do otherwise.
b) Soft determinism: We are free to do otherwise if we want to do otherwise—although we are not free to want to do otherwise.
c) Indeterminism: We are free to want to do otherwise.
The Westminster Confession implicitly opts for (b). Cf. WCF 3.1; 4:2.
An example of hard determinism would be Frankfurt-cases. A Frankfurt-case is a thought-experiment in which the subject, unbeknownst to himself, has a failsafe device implanted in his brain which would prevent him from making a certain choice.
Frankfurt-cases are generally deployed to show that LFW is not a necessary condition of moral responsibility. But aside from their relevance to the ethical issues raised in the debate between compatibilism and incompatibilism, they are also relevant to the epistemic question of what would count as evidence for LFW, were it true.
The problem which Frankfurt-cases pose for libertarians is that the subject of the experiment believes himself to be free, even though he isn’t. There is nothing in his experience to falsify his belief that he is other than free, even though his belief is false.
On this view, not only is hard determinism compatible with moral responsibility, it is also compatible with the illusion LFW.
It is not my purpose to make a case for hard determinism. Rather, I’m arguing from the greater to the lesser. If the indeterminist can’t even disprove hard determinism, he can scarcely disprove soft determinism.
The problem is that an agent is in no position to know, from the inside out, whether his actions are determined by an external source.
As such, this question can only be resolved by revelation rather than reason.
iii) Finally, I’d like to raise another objection to LFW. Since we’ve all grown up on SF, we’re all familiar with the paradoxes of time-travel. And this is one reason to believe that time travel and retrocausation are impossible.
In a typical case, a scientist goes back in time and accidentally kills his father before is father has a chance to father him. But to change the future in that respect would remove a necessary condition for the experiment in the first place, since the son would not exist in the future to go back in time and accidentally kill his own father.
Now, I submit that if LFW were true, it would raise this conundrum to a global level. The typical form of the paradox assumes that a time traveler must intervene in the past to change the past in order to change the future.
But, if LFW were true, no such intervention would be needed to change the future. It would be inessential to alter the past in order to alter the future.
Rather, all you’d need to do, to alter the future, would be to exactly replicate the past. For the leading principle of LFW is that an agent is free to do otherwise under the very same circumstances.
And this, I submit, carries a further implication. If LFW were true, and you kept replicating the past, then, of necessity, the same agent would do otherwise in the same situation. If he really could do otherwise, and you keep giving him enough chances to do otherwise, he would do otherwise—sooner or later.
But if enough past agents were to do otherwise, the future would be so different that the experiment could not be performed in the first place.
Hence, I conclude that LFW is incoherent on the same grounds as retrocausation.