DIVINE ATTRIBUTES: FOREKNOWLEDGE


Readings:
St. Thomas Aquinas, Summa Contra Gentiles I, chap. 67
Alvin Plantinga, "On Ockham's Way Out"


A. The Elements of Divine Foreknowledge of Future Contingents

1. SCG I, 67:

Notice from the beginning how St. Thomas distinguishes the knowledge had by God from the knowledge had by creatures. God's foreknowledge is a consequence of His providential guidance of the world, according to which he chooses and executes a plan for the world from all eternity. So God's certain foreknowledge of future contingents is not like that of a predictor who has no or little control over what he predicts. Note that St. Thomas alludes to Scriptural evidence for divine foreknowledge, viz., Wisdom 8:8, Ecclesiasticus 39:24-25, and Isaia 48:5.

St. Thomas gives a series of arguments to show that God has certain knowledge of future contingents, yet a knowledge of them that does not take away their contingency:

    a. One cannot have certitude about a future contingent insofar as it is future; but, because of his eternality, God's intuitive grasp of future contingents is like our intuitive grasp of present contingents. That is, God sees, say, Jones' mowing his lawn next week in just the way that I see you sitting here now. My perceptual knowledge is certain even though your sitting here now is contingent; so too God's intuitive knowledge of Jones's mowing the lawn next week is certain even though Jones's mowing is a future contingent. (Note: The point here is that, unlike us, God is no more present to one time than to another; perhaps better, every moment of time is equally accessible to God's knowledge, just as every part of space is equally accessible to God's knowledge.

    b. The contingent differs from the necessary in the way in which they emanate from their causes. For instance, the water's boiling issues necessarily from its immediate causes, while my freely deciding to go to the movies emanates contingently from its immediate cause, viz., my will. But taken as they are in themselves the boiling and the deciding are two just two beings and are known as such by God, even independently of their relation to their causes. So God can have certain knowledge of both of them from eternity through their intrinsic being, even though the one does not emanate necessarily from its causes.

    c. But God also knows things through their causes, and with respect to future contingents He knows all the causes and all the possible impediments and whether the causes will be impeded. Therefore, He has certain knowledge of future contingents through their causes.

    d. Because we are imperfect and get our knowledge from things, we often have only probable cognition of necessary things; God, because He is perfect and is the first cause of the things known, has certain cognition of contingent things.

    e. Contingent causes have contingent effects; therefore contingent proximate causes have contingent effects, even if some of the remote causes are necessary. God's knowledge is a remote cause of things; so that knowledge can be a necessary cause (like the sun) of contingent effects, as long as some of the intermediate causes are contingent.

    f. God's knowledge is perfect and is the source of all being and of all causes. Therefore God has perfect knowledge of the order of causes that produces a contingent effect; but this order is such that the effect proceeds from it contingently; therefore God knows this effect and knows that it is contingent.

    g. God's knowledge is prior to (not, like ours, posterior to) the things known. Therefore God's knowledge antecedently encompasses all the possible changes and possible impeding causes in the world, since God gives being and action to everything. Therefore, unlike us, God can have certain and unchangeable knowledge of future things that are in themselves contingent and liable to change.

    h. Even though our statement 'God foreknows that this will occur' assumes an intermediate temporal position between God's knowledge, which is from eternity, and the future contingent, which is in our future, God's knowledge itself is related equally to each moment of time. So when arguments of the sort articulated below come up, they attribute to God's knowledge a modality (viz., temporal position between eternity and the future) which it does not really have.

    i. St. Thomas's reply to first argument below (B1).

2. The definition of omniscience:

    (D1) S is omniscient just in case for any proposition p, S knows whether or not p is true.

    (D2) S is omniscient just in case for any proposition p, either S knows that p is true or S knows that the negation of p is true.

    (D2*) S is omniscient just in case for any proposition p, either S knows that p is true or S knows that the negation of p is true; and for every future-tense proposition Fp, either S knows Fp or S knows FNp.

    (D3) S is omniscient just in case for any proposition p, such that it is possible for someone to know whether or not p is true, S in fact knows whether or not p is true.

    NOTE: Only (D2*) requires that an omniscient being have comprehensive knowledge of the future.


B. On Ockham's Way Out

1. First argument for the incompatibility of divine foreknowledge and human freedom.

a. The argument:

    Suppose that t is far in our future and that Socrates's sitting at t is taken as a paradigmatic example of a future contingent. Then the argument goes as follows:

    (1) God knows (believes) that Socrates will sit at time t. [assumption that there is divine foreknowledge of future contingents]

    (2) If God knows (believes) that Socrates will sit at time t, then it must be the case that Socrates will sit at time t. [premise expressing certainty of God's knowledge]

    (3) Therefore, it must be the case that Socrates will sit at time t. [from (1) and (2).

    (4) If it must be the case that Socrates will sit at time t, then Socrates does not have the power to refrain from sitting at time t. [premise]

    Therefore, Socrates does not have the power to refrain from sitting at t, and so Socrates is not free with respect to sitting at time t. [from (4) and (5), plus the obvious connection between power and freedom]

b. The reply (from St. Thomas):

One popular argument for the incompatibility of divine foreknowledge and human freedom contains the premise If God knows (believes) that Socrates will sit at time t, then it must be the case that Socrates will sit at time t, what I say Ücan be taken in two ways. This premise may mean

    It must be the case that if God knows (believes) that Socrates will sit at time t, then Socrates will sit at time t,

where the necessity is attributed to the whole conditional proposition; that is, it is the necessity of the consequence. If this is what the proposition in question means, then it cannot be used to derive (3) validly from (1) and (2).

On the other hand, the proposition in question may mean

    If God knows (believes) that Socrates will sit at time t, then it must be the case that Socrates will sit at time t,

where the necessity is attributed to consequent alone; that is, it is the necessity of the consequent. But then the premise presupposes what it is trying to prove, viz., that God's foreknowledge imposes necessity on things.


2. Second argument for the incompatibility of divine foreknowledge and human freedom.

a. The argument:

    Suppose that t is far in our future and that Socrates's sitting at t is taken as a paradigmatic example of a future contingent. Then the argument goes as follows:

    (1) The proposition God believes that Socrates will sit at time t is true now. [assumption]

    (2) If a proposition p is true now, then its past-tense counterpart will always be (accidentally) necessary from now on. [principle governing which propositions share in the necessity of the past]

    (3) So the proposition God believed that Socrates will sit at time t will always be necessary from now on. [from (1) and (2)]

    (4) Now the proposition God believed that Socrates will sit at time t entails the proposition If t is the present moment, then Socrates is sitting. [premise]

    (5) But if (i) a proposition p will always be (accidentally) necessary from now and (ii) p entails q, then no one will ever have the power to cause q to be false. [principle relating (accidental) necessity to freedom and power]

    Therefore, no one (including Socrates) will ever have the power to cause If t is the present moment, then Socrates is sitting to be false; that is, no one (including Socrates) will ever have the power to cause Socrates is sitting to be false at t, and so Socrates is not free to refrain from sitting at t. [from (4) and (5)]

But what applies to this action of Socrates's obviously applies to all alleged future contingents. Therefore, divine foreknowledge is incompatible with human freedom.

b. Possible replies:

i. Deny the assumption (1)

    Aristotelianism: Deny (1) because no future contingent proposition is true and hence none can be known by God. Problem: simply denies divine foreknowledge, which has very strong Scriptural, Patristic, and Conciliar support, as well as philosophical support.

    Thomism: Deny (1) because it falsely situates God's knowledge between eternity and the future; but this is not literally true since God's knowledge is equally related to all moments of time.

    Problem: It appears that the very same argument could use the premise It is now true that God eternally knows that Socrates sits at time t.

ii. Deny the premise (4)

    Geachism: Deny (4) on the grounds that all propositions ostensibly about the future are really about present tendencies. So even if the proposition Socrates will sit at time t is true now and known by God now, it might still be the case that Socrates is not sitting when t rolls around. For the proposition in question means only that the world is now tending toward Socrates's sitting at t, and this tendency might be counteracted before t.

iii. Deny the principle (2)

    Ockhamism: Deny (2) on the grounds that not it does not apply to every proposition and, in particular, it does not apply to future-tense propositions or to propositions like God knows that Socrates will sit at time t, which imply future-tense propositions. So, for instance, the proposition It was true Socrates will sit at time t is not now necessary, and so neither is the proposition God knew that Socrates will sit at t.

    Problem: It seems implausible to think that God's foreknowledge from eternity is not now immutably fixed; also, there is a problem here with prophecy, since Ockhamism seems to entail that there can be no certain and infallible prophecy of creaturely free actions.

iv. Deny the principle (5)

    Molinism: Deny (5) on the grounds that a Molinist conception of divine providence provides a picture on which (1)-(4) might be true even if the conclusion is false. The idea is this: Socrates still has the power to do something at t in circumstances C, viz., refrain from sitting, such that if Socrates were to do it at t in C, then God would not have known from eternity that Socrates was going to do it at t in C. The claim that Socrates has this power is substantiated by pointing out that all the causal contributions of agents other than Socrates are arguably compatible with his sitting and compatible with his not sitting. What more is then required for freedom?

    Problem: The usual problems with Molinism, plus some qualms about what this notion of the necessity of the past might amount to.

3. Newcombe's Paradox

There are two boxes, A and B, and you have two choices: (i) to take box A alone, and (ii) to take both box A and box B. You get whatever money is in the boxes you take and your greedy goal is to get as much money as you can from the boxes. Eighty years ago Carlos Houdini put money into the boxes and no one has touched the boxes since then. Box A contains either $1 million or nothing; box B contains either $1 thousand. Carlos decided what to do with box A in the following way: if he predicted that you would take box A alone, then he put $1 million into box A; if he predicted that you would take both box A and box B, he put nothing in box A. One further fact: in past performances Carlos guessed right in 93.6% of the cases, and so the vast majority of those who have taken both boxes have ended up with just $1 thousand.

Why is this like the present situation? Because if we replace Carlos with God and replace Carlos's 93.6% success rate with God's guaranteed 100% success rate, then we can construct a knock-down proof that you should take box A alone. And the relevance to the foreknowledge/freedom debate is this: Suppose that box A contains $1 million dollars. It follows that you will choose box A alone. But this is compatible with its being the case that you have the power to do something, viz., taken both boxes, which is such that if you were to do it, then God would have known this from all eternity and so would have put nothing in box A. The following is thus true:

    (P) You now have the power to do something, viz., choose both boxes, such that if God had known from eternity that you would freely do it in these circumstances, then box A would not now contain $1 million.

Notice that this is similar to the Abraham case. Assume that Molinism is the correct view about divine providence. Suppose that even though God has chosen our world, call it gamma, the following is true: On December 21, 1989 at 5PM you are sorely tempted to cheat on the final exam in this course; as a matter of fact you will freely refrain from cheating, and lucky for all of us. For, unbeknownst to you, if God had known from all eternity that you would freely cheat in those circumstances, then he would have decided to create world delta instead--and, sad to say, if he had created delta then none of us would have existed and neither would Abraham. The following is thus true:

    (Q) On December 21, 1989 at 5PM you have the power to do something such that if God had known from eternity that you would do it in those circumstances, then Abraham would never have existed.

4. Accidental Necessity

How should we think of the necessity of the past? I do not want to go into this in any detail, but this is another case in which interest in theological problems has led to some of the most interesting philosophical work in the area and also to the rediscovery of a lot of sophisticated medieval treatments of the matter.