Q&A: A Question for the Rabbi

Originally published: July 11, 2017

This is an English translation (via GPT-5.4). Read the original Hebrew version.

A Question for the Rabbi

Question

This has been ground exceedingly fine, and the Rabbi has surely written about it, but at the moment I can’t find it.
How, and whether, can one reconcile between God’s knowledge and human free choice?
Thank you, and sorry for touching on such a banal question, but all I find are approaches claiming that one has to accept both ideas simultaneously, and that any other position makes you a “heretic.”
What is the Rabbi’s opinion on this issue?

Answer

My opinion is that this is a logical contradiction, and therefore you have to choose one of these two beliefs. I choose our freedom of will and reject God’s prior knowledge. I explained this in my book The Science of Freedom. You can see a brief discussion in the article here:

מבט שיטתי על חופש הרצון

Here is the relevant passage:
Against Determinism 2: Newcomb’s Paradox
Another a priori consideration against determinism is Newcomb’s paradox. The philosopher Robert Nozick, in his 1969 article, presented the following thought experiment. It involves two people: the chooser and the predictor. In front of the chooser are two boxes: one open, containing $1,000, and the other closed, containing either $0 or $1,000,000 (the chooser does not know which). The chooser must decide whether to take the contents of both boxes together, or only the contents of the closed one. Here the predictor enters the picture; for the sake of discussion, we assume his predictive ability is perfect. The predictor knows in advance, with certainty, what the chooser will do, and based on that he prepares the contents of the closed box a day before the chooser makes his decision. Since the predictor wants to reward someone who is satisfied with less, he adopts the following tactic: if the chooser is going to take both boxes, he makes sure in advance that there will be no money at all in the closed box. But if the chooser is someone who is satisfied with less and is going to take only the closed box, the predictor rewards him by placing a million dollars inside it.
The chooser himself knows the predictor’s policy and abilities. The only thing he does not know is this one detail: what the predictor predicted regarding his present expected choice, and therefore he also does not know what the predictor actually put in the closed box. The question is which strategy the chooser should adopt. Should he take only the closed box, or both of them?
Seemingly, he should take only the closed box, because then he will win a million dollars, whereas if he takes both he will win only a thousand (because the closed one will be empty). On the other hand, the box is already closed before him now, and whatever is inside it was already determined yesterday and will not change if he acts differently. If so, why shouldn’t he take the closed box as he intended, but then also take the open one with another thousand dollars? After all, taking the second box cannot retroactively change the contents of the closed box lying before him (our assumption is that the predictor is all-knowing but not necessarily all-powerful). It seems that taking both boxes is the winning strategy in any case. That way he gets the contents of the closed box plus another thousand dollars. That is always better than the contents of the closed box alone. But if the predictor truly is all-knowing, he will ensure that in such a case the closed box will be empty. If so, when the chooser takes both, he will win only $1,000—that is, he chose incorrectly. Alternatively, the predictor did not predict correctly, which contradicts the assumption that he is an all-knowing predictor.
To understand the root of the problem, we must note that the assumption that there is such a predictor already smuggles in a disguised deterministic position. In the libertarian picture, one cannot speak of such a predictor, because it is impossible to know with certainty in advance what the chooser will decide. If the information does not now exist, how can anyone know it with certainty? “Knowing information that does not exist” is a self-contradictory phrase; similarly, a predictor who foresees in advance the decision of a person who chooses freely is an oxymoron. Predictive ability is defined where the information exists in principle—that is, where it can be derived from the present circumstances. But in the libertarian picture the information does not exist at all now, and therefore no one, however great his predictive powers may be, could ever predict the future. The libertarian will argue against Nozick and Newcomb that there is no such predictor. The concept contains an internal contradiction, and therefore the problem never arises at all. The libertarian would of course take both boxes.
By contrast, in the deterministic picture the difficulty remains in force. There the assumption is that the information does exist. Even if no one can access it (because it is an extremely complex and complicated calculation; there is no computer powerful enough to predict it), there is no principled obstacle to the existence of a predictor who knows it. The concept contains no internal contradiction. From this it follows that Newcomb’s paradox is actually an a priori argument against determinism, because if determinism is correct then the information really does exist and such a predictor is possible in principle—and then we enter a logical loop. According to the determinist, the chooser must make a plainly irrational decision (not take the thousand dollars lying before him, and settle for the closed box alone), or alternatively he must believe in causal influence backward in time (that taking the box retroactively changes its contents). Which proves, then and there, that determinism is patently unreasonable.
To exhaust the discussion we would have to continue through several more twists in the plot (such as what it means to “make a decision” for the determinist), and I cannot do that here. I refer the interested reader to the fourth chapter of my book. For the purpose of the discussion in the last chapter I will only remark that if a person really does have free choice, then it cannot be that there exists any such all-knowing being, even if it is the Holy One, blessed be He, Himself. This is a logical contradiction, without any assumption about the nature of that all-knowing predictor.

Discussion on Answer

Y.D. (2017-07-11)

So then what place is there for prophets, and for prophecies of reward and punishment, and for “not one of Your words will return empty”?

Michi (2017-07-11)

There are situations in which the Holy One, blessed be He, intervenes and takes the reins into His own hands. In that case, we indeed have no choice. Ordinary prophecies are matters of possibility (what is expected to happen if unusual acts of choice are not taken—an optimal assessment of the future). The Shelah already discussed this at length in his introduction, Beit HaBechirah; see there.
It seems to me that “not one of Your words will return empty” refers not to prophecies but to promises.

A Question for the Rabbi

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