Middle Knowledge

If Aristotle had not been a student of Plato, then would Aristotle
have chosen to start his school at Lyceum? If you believe God knows
the answer to this question, you probably believe God has middle
knowledge.

Middle knowledge is a form of knowledge first attributed to God by the
sixteenth century Jesuit theologian Luis de Molina (pictured to the
left). It is best characterized as God's prevolitional knowledge of
all true counterfactuals of creaturely freedom. This knowledge is seen
by its proponents as the key to understanding the compatibility of
divine providence and creaturely (libertarian) freedom (see Free
Will).

1. Assumptions

Before an examination of the theory of middle knowledge can be
offered, several assumptions must be set forth. Each of these
assumptions is important for an understanding of the doctrine of
middle knowledge and its usefulness for theological reflection.

First, it is assumed that for an action to be free, it must be
determined by the agent performing the action. This means that God
cannot will a free creature to act in a particular way and the act
still be free. Free actions must be self-determinative. This
assumption may appear self-evident to some, and quite controversial to
others. While it must be admitted that God could certainly desire a
creature act in a particular way and the choice remain free, it is
difficult to see how He could cause the choice and it still be free in
a meaningful way. Proponents of middle knowledge do not deny that God
may influence a free choice or persuade an agent to act in a
particular way, but such influence and persuasion cannot be
determinative if the action performed is to be free. In addition,
middle knowledge requires freedom of a libertarian nature. That is,
free creatures have the ability to choose between competing
alternatives, and really could choose one or the other of the
alternatives.

Second, it has become customary to speak of a logical priority in
divine thoughts. This is not to deny the simplicity or omniscience of
God, or to say that He gains knowledge that He did not previously
possess. Rather, it is simply to acknowledge that dependency
relationships exist between certain kinds of knowledge. It is also to
acknowledge that something analogous to deliberation may take place in
the divine mind. For example, in order for God to know that one plus
one equals two, He must first comprehend the meaning of the concepts
represented by the numbers, mathematical symbols, and formulaic
expressions; they serve as a basis by which the truthfulness of the
formula may be evaluated. But this is not to say that there was a time
when God did not know 1+1=2. Thus, a relationship of logical priority,
but not necessarily temporal priority exists between some of the
content of divine knowledge.

Third, proponents of the doctrine of middle knowledge believe that
things could have been different than they, in fact, are. There is
much that is not necessary about the way the world is. For example, I
could have married someone other than Stefana, the woman I did marry.
Of course, that would depend upon my falling in love with someone else
and that woman agreeing to my proposal of marriage. Although I find it
difficult to imagine my falling in love with someone else (I love my
wife very much), the point is that there is nothing about my marrying
Stefana that is necessary. Stefana was free to reject my offer of
marriage, I was free to never ask her out, we may never have existed,
etc. Or, for another example, God could have made things differently.
The sky could be yellow instead of blue, or the grass pink. God could
have chosen to not create at all. Although this assumption should be
self-evident, it is also supported by the Heisenberg Uncertainty
Principle. Things could have been different.
2. Scientia Media

Molina's doctrine is called scientia media, or middle knowledge,
because it stands in the middle of the two traditional categories of
divine epistemology as handed down by Aquinas, natural and free
knowledge. It shares characteristics of each and, in the logical order
of the divine deliberative process regarding creation, it follows
natural knowledge but precedes free knowledge.

Natural knowledge is that part of God's knowledge which He knows by
His very nature or essence, and since His essence is necessary, so is
that which is known through it. That is, the content of natural
knowledge includes all metaphysically necessary truths. For example,
the statement, "All bachelors are unmarried" is both necessary and
part of natural knowledge. Other examples include other tautologies,
mathematical certainties (e.g., 1+1=2), and all possibilities (since
all possibilities are necessarily so). Natural knowledge can therefore
be thought of as including a virtually infinite number of propositions
of the form, It is possible that p, as well as a number of
propositions of the form, It is the case that p. Thus, natural
knowledge, properly conceived, is that part of God's knowledge which
could not have been different from what it is. It follows from this
fact that the content of God's natural knowledge is independent of His
will; God has no control over the truth of the propositions He knows
by natural knowledge. Consider, for example, the mathematical truth,
1+1=2. No matter what God wills, it will always be true that the
concepts represented by the symbols 1, 2, +, and =, when arranged in a
formulaic expression, one plus one equals two. It is important to note
that, because natural knowledge is independent from God's will and, to
some extent, places limits upon the kinds of things God can do,
natural knowledge informs(ed) God's decision(s) regarding His creative
work. This also means that natural knowledge is prevolitional.

Free knowledge is that part of God's knowledge which He knows by His
knowledge of His own will, both His desires and what He will, in fact,
do. The content of this knowledge is made up of truths which refer to
what actually exists (or has existed, or will exist). For example, the
statement, "John Laing exists," although certainly true, is dependent
upon God's choice to create me (or, more properly, to actualize a
world where I am brought about), and hence, is part of God's free
knowledge. Free knowledge can therefore be thought of as including a
number of propositions of the form, It is the case that p (Note that
propositions of the forms, It was the case that p, and It will be the
case that p, can be reduced to a proposition which refers to the
present). Since free knowledge comes from God's creative act of will,
two things follow. First, the content of that knowledge is contingent;
it could have been different from what it, in fact, is. That is, free
knowledge includes only metaphysically contingent truths, or truths
that could have been prevented by God if He chose to create different
situations, different creatures, or to not create at all. Second, free
knowledge is postvolitional; it is dependent upon God's will.

As previously noted, middle knowledge is so named because it comes
between natural and free knowledge in God's deliberations regarding
the creative process. According to the theory, middle knowledge is
like natural knowledge in that it is prevolitional, or prior to God's
choice to create. This, of course, also means that the content of
middle knowledge is true independent of God's will and therefore, He
has no control over it. Yet, it is not the same as natural knowledge
because, like free knowledge, its content is contingent. The doctrine
of middle knowledge proposes that God has knowledge of metaphysically
necessary states of affairs via natural knowledge, of what He intends
to do via free knowledge, and in addition, of what free creatures
would do if they were instantiated (via middle knowledge). Thus, the
content of middle knowledge is made up of truths which refer to what
would be the case if various states of affairs were to obtain. For
example, the statement, "If John Laing were given the opportunity to
write an article on middle knowledge for the Internet Encyclopedia of
Philosophy, he would freely do so," although true, is certainly not
necessarily so. I could easily have refrained from writing, if I were
so inclined (or too busy, etc.). Likewise, its truth does not seem to
be dependent upon God's will in the same way that "John Laing exists"
is. Even if God chose to not create me, the statement regarding my
writing the article could still be true. In fact, its truth does not
seem to be dependent upon God's will at all, but rather upon my will.
One of the basic assumptions of the doctrine of middle knowledge
outlined above is that God cannot will a creature to freely choose
anything. Thus, the content of middle knowledge can be thought of as
including a virtually infinite number of propositions of the form, If
person, P, were in situation, S, then P would freely perform action, A
(or P(S®A)).

The theory of middle knowledge presents a picture of divine
omniscience which includes not only knowledge of the past, present and
future, but also knowledge of conditional future contingents
(propositions which refer to how free creatures will choose in various
circumstances), counterfactuals (propositions which refer to how
things would actually be if circumstances were different than they are
or will be), and counterfactuals of creaturely freedom (propositions
which refer to what a free creature would have chosen (freely) to do
if things had been different). This knowledge, together with natural
knowledge, informs God's decision about what He will do with reference
to creation.

One of the most useful concepts for the explanation and evaluation of
middle knowledge is that of possible worlds. The basic belief that
things could have been different is commonly described as belief in
many possible worlds. Each complete set of possible states of affairs
(or way things could be) is a possible world, and although there is an
extremely large number of possible worlds, it is not infinite (some
states of affairs are impossible), and only one is actual (the way
things are).

In the contemporary discussion of possible worlds, two concepts have
proven particularly instructive: actualization and similarity. In
popular piety, it is not unusual to refer to God creating the world.
However, in possible worlds semantics, this is seen as semantically
improper. Instead, God's creative activity should be referred to as
creating the heavens and the Earth, but actualizing a particular
possible world (since possible states of affairs do not have a
beginning, which the language of creation implies). According to the
doctrine of Molinism, God can actualize a world where His will is
brought about by the free decisions of creatures, but in order to make
this claim, contemporary Molinists have had to distinguish between
strong and weak actualization. Strong actualization refers to the
efforts of a being when it causally determines the occurrence of an
event (e.g., God causes something to happen), while weak actualization
refers to the contribution of a being to the occurrence of an event by
placement of a free creature in circumstances in which he will freely
cause the event. Weak actualization has proven to be a powerful tool
for understanding the relationship between God's providence and human
freedom. However, it must be noted that it implies that there may be
some states of affairs that God cannot weakly actualize, which leads
to the further conclusion that there may be some possible worlds that
God cannot actualize.

A more controversial aspect of modern Molinism has been the use of
possible worlds in determining the truth of counterfactuals. According
to possible worlds semantics, a counterfactual is true in the actual
world if it is true in the possible (but not actual) world that is
most similar to the actual world. Not all Molinists have accepted this
approach, noting the difficulty in determining comparative similarity
among possible worlds.
3. Objections to Middle Knowledge

Much of the current discussion of middle knowledge has developed in
the context of debate over the validity of the doctrine. Three basic
objections to Molinism have been proffered: 1) Rejection of
Libertarian Free Will, 2) The Truth of Counterfactuals of Creaturely
Freedom, and 3) The Usefulness of Middle Knowledge for God's Creative
Decision.
a. Rejection of Libertarian Freedom

The principle objection to middle knowledge in Molina's day was that
it afforded creatures such a high view of freedom that God's
providence was compromised. Although Molina's detractors were
certainly motivated by political concerns, the strength of their
theological and philosophical arguments cannot be denied. Today, this
form of argument normally takes one of two forms. First, some
theologians/philosophers have objected to the assumption that God
cannot will the free actions of creatures. This argument will often be
based on an appeal to mystery or the transcendence of God. God, it is
said, works on a plane above that of creatures, and therefore can will
an action of an individual while not impinging on his freedom. Second,
and more commonly, some have objected to the concept of libertarian
freedom and instead advocate compatibilist freedom. Whereas
libertarian freedom is seen as the ability to choose between competing
alternatives, compatibilist freedom is seen as the ability to choose
in accordance with one's desires. It is argued that libertarian
freedom is radically indeterministic or even incoherent—if one's
desires are not determinative for his decision, then it appears that
no decision can be made.
i. Libertarian Responses

Proponents of libertarian freedom have responded that it is the
individual's will which is determinative for the choice made. They
have also pointed out that proponents of compatibilist freedom must
believe that God possesses libertarian freedom in order to avoid
theological fatalism: either God was able to choose to create or not
create, for example, or He had to create. Since most theologians want
to avoid the claim that God could always act in only one way, they
must admit the coherence of libertarian freedom. At this point, then,
the complaint with libertarian creaturely freedom can only be one of
veracity—that it simply does not accurately explain the creaturely
decision-making process. Proponents of libertarian freedom have
pointed out that this claim cannot be proven, and that from an
existential standpoint, it seems to be false. It should be noted that
the majority of philosophers hold to libertarian freedom and these
objections have been primarily entertained in the theological arena.
b. The Truth of Counterfactuals of Creaturely Freedom

The second type of objection to Molinism is really an attack on the
belief, fundamental to the doctrine of middle knowledge, in
counterfactuals of creaturely freedom. Many scholars have called into
question the possibility that counterfactuals of creaturely freedom
can be true. Various approaches have been taken to make this claim,
from questioning the principle of conditional excluded middle, to
arguing that true counterfactuals require determinism, to contending
that counterfactuals of creaturely freedom have nothing which makes
them true. Each will be presented, albeit only briefly.
i. Objections to the Principle of Conditional Excluded Middle

The first approach to arguing that counterfactuals of creaturely
freedom cannot be true has come in the form of an attack on the
principle of conditional excluded middle. The principle of conditional
excluded middle states that, given two conditional statements with the
same antecedent and opposite consequents, one must be true (Either p®q
or p®~q). It is thought that Molinism requires the principle to hold
because counterfactuals of freedom are often presented in pairs. For
example, consider the following pair of conditional statements:

(1) If John were to ask Stefana to marry him, she would accept; and

(2) If John were to ask Stefana to marry him, she would not accept.

Although, properly speaking, these are not counterfactuals, since I
did ask Stefana to marry me, in the literature it has become customary
to speak of all conditional statements of this sort as
counterfactuals. According to the doctrine of middle knowledge, one of
either (1) or (2) must be true, and God knew which would be true prior
to His free knowledge. However, if conditional excluded middle can be
shown to be false, then the contention that one of a pair of
counterfactuals must be true, cannot be sustained.

David Lewis has provided an example of two conditional statements
which (he claims) seem equally true:

(3) If Verdi and Bizet were compatriots, Bizet would be Italian;

(4) If Verdi and Bizet were compatriots, Bizet would not be Italian.

It is unclear which statement is correct, yet according to CEM, one
must be true. (3) could be true. After all, if Bizet were Italian, he
and Verdi would be compatriots. However, (4) could also be true (if
Verdi were French). It seems just as likely for Verdi to have been
French as Bizet to have been Italian and therefore, neither (3) nor
(4) is true. The principle of conditional excluded middle fails, and
so does middle knowledge.
ii. Molinist Responses

Two basic responses have been offered by proponents of Molinism.
First, some have questioned the accuracy of Lewis' contention that (3)
is just as likely to be true as (4). In deciding which is true, a
judgment call has to be made regarding the relative similarity of
possible worlds to the actual world, a. Suppose (3) is true in a
possible world, b, and b is more similar, or closer, to a than any
other possible world in which (3) is true. Suppose further that (4) is
true in a possible world, g, and g is closer to a than any other
possible world in which (4) is true. According to the standard
possible worlds semantics, (3) is true if b is closer to a than g is,
and (4) is true if g is closer to a than b is. However, Lewis argues
that b and g may be equally similar to a and therefore, neither (3)
nor (4) is true—they have an equal chance of being true.

However, it seems that this is not the case—the inability to determine
which possible world, b or g, is closer to the actual world, a,
appears to be due more to a lack of knowledge about the actual world
than genuine indeterminacy regarding similarity among worlds. It may
also be due to a lack of criteria regarding how similarity among
possible worlds is to be determined. Thus, the inability to determine
which of (3) or (4) is true may be due to epistemological uncertainty
rather than equal likelihood.

Second, it has been pointed out that middle knowledge does not require
the principle of excluded middle, but rather only the principle of
bivalence. Lewis' example does not present a problem for middle
knowledge because the counterfactuals do not refer to creaturely
activity and because two kinds of change are possible (Bizet could be
Italian or Verdi could be French). In a counterfactual of creaturely
freedom, only one sort of change is possible—either the creature
performs the required action, or he/she does not. The only variable in
the example given previously was Stefana's action in response to the
proposal. She could either accept, or not accept. Since only one
variable exists, only the principle of bivalence is necessary.
iii. Molinism and Determinism

The second approach to arguing that counterfactuals of creaturely
freedom cannot be true has come in the form of an assertion that
Molinism leads to determinism and therefore, the counterfactuals do
not refer to free actions. Several forms of this argument have been
offered.

The first form has been to question the amount of risk God takes.
Since middle knowledge affords God comprehensive knowledge of the
future (when taken with His free knowledge), and of how creatures will
exercise their freedom when faced with decisions, and since that
knowledge is used by God in determining how He will providentially
guide the world, all risk on God's part is removed; He cannot be
surprised and further, He specifically planned for everything that
will occur. Yet, the objectors argue, true creaturely freedom requires
risk on the part of God. Molinism removes the risk, but is doing so,
abrogates creaturely freedom.

The most common response by Molinists to this form of the argument is
simply that it begs the question of compatibilism. It is based on the
questionable presuppositions that divine risk is necessary for
creaturely freedom to exist, and that risk is eliminated by divine
foreknowledge. But these presuppositions seem to assume
incompatibilism (of creaturely freedom and divine foreknowledge),
which is what the argument is supposed to prove. In addition,
Molinists have also argued that it is dependent upon a particular view
of risk that may be questioned as well.

The second form of the argument contends that the individual referred
to in a counterfactual of creaturely freedom does not have the power
to bring about the truth or falsity of that counterfactual and
therefore, does not have the required freedom to perform, or not
perform, the given action. The reason it is argued that individuals do
not have the power to bring about the truth of counterfactuals about
them is that some counterfactuals are true regardless of what the
individual actually does. Consider the example given earlier in this
article:

(1) If John were to ask Stefana to marry him, she would accept; and

(2) If John were to ask Stefana to marry him, she would not accept.

(1) is true, but according to this argument, Stefana does not bring
about its truth because it is true whether or not she accepts. Suppose
John never proposes—in that case, Stefana neither accepts nor rejects
the offer because it was never made. That is, the counterfactual is
true independent of Stefana's action and, therefore, she does not make
it true. So, the argument goes, since Stefana does not have the power
to bring it about that the counterfactual is true, then she does not
have the power to bring it about that the counterfactual is false. But
since the counterfactual is true, it seems that she therefore does not
have the power to not accept the proposal if it is made and therefore,
she is not free with respect to the marriage proposal.

The proponents of middle knowledge have responded to this form of the
argument with a variety of answers, most of which are rather complex
discussions of the concepts of individual power and entailment,
relative similarity among possible worlds, and bringing about. The
upshot of these arguments is that it is not at all clear (at least to
the Molinists) that individuals do not have the power to bring about
the truth (or falsity) of counterfactuals which refer to them. In
fact, most Molinists have argued for the validity of the concept of
counterfactual power over the past (power of an individual to act in
such a way that certain things in the past would have been other than
they were, if the person were going to act in that way, which they
were not).

The third form of the argument builds upon the first and the second,
specifically with reference to the way that God makes use of middle
knowledge and the fixity of the past. Since God's knowledge of
counterfactuals of creaturely freedom informs His decision about which
possible world to actualize, that knowledge and the true
counterfactuals are part of the causal history of the actual world and
therefore, are part of the fixed past. The problem this causes for
Molinism is due to the fact that genuine freedom requires that the
individual has the ability to either act in the specified manner or
not act in the specified manner. In other words, if God considered (1)
in his decision regarding actualization of this world, once He did
actualize this world (in which (1) is true), then (1) became part of
the history of this world and part of the fixed past. This leads to
the suggestion that Stefana did not really have the ability to not
accept the offer of marriage, if John were to propose (that is, to
bring it about that (2) is true instead of (1)).

Molinists have responded to this objection by denying the central
claim that events which had causal consequences in the past are hard
facts about the past. Most Molinists believe that free agents have
counterfactual power over the past (power to act such that, if one
were to act in that way, the past would have been different from how
it, in fact, was). If this sort of power is accepted as plausible,
then the objection fails.
iv. The Grounding Objection

The third approach to arguing that counterfactuals of creaturely
freedom cannot be true is the most popular and seems to serve as the
basis for the other objections. It is typically referred to as the
"grounding objection," and is related to the question already posed
regarding what causes counterfactuals to be true. According to the
argument, there appears to be no good answer to the question of what
grounds the truth of counterfactuals of creaturely freedom. They
cannot be grounded in God because determinism would follow—the
necessity of God's being or His will would transfer to the
counterfactuals. Additionally, the prevolitional character of middle
knowledge speaks against grounding counterfactuals of creaturely
freedom in the will of God. However, they also cannot be grounded in
the individuals to which they refer for at least four reasons. First,
counterfactuals of creaturely freedom are true prior to the existence
of the individual to which they refer. Second, the existence of the
individuals is dependent upon the will of God, and therefore, the
truth of the counterfactuals would also be dependent upon the will of
God (which has already been shown to be problematic). Third,
counterfactuals, properly speaking, refer to non-actual states of
affairs and therefore, the events to which they refer never happen,
and fourth, psychological makeup cannot serve as grounding because
this suggests that the actions performed are not free and thus, the
propositions describing the decisions/actions cannot be deemed
counterfactuals of freedom.
v. Molinist Responses

Molinists have responded to the grounding objection in a variety of
ways, five of which will be surveyed here. The first response to the
grounding objection has been to simply state that counterfactuals of
freedom do not need to be grounded and that no satisfactory
explanation of the grounding relation can be given. The upshot of this
response is that counterfactuals of creaturely freedom seem to be
brute facts about the possible worlds in which they are true or brute
facts about the creatures to whom they refer.

The second response is similar in that it turns the grounding
objection against the detractor of middle knowledge. Some of the
proponents of middle knowledge have suggested that the grounding
objection is based on the assumption that a causal connection must
exist between the antecedent and consequent of a counterfactual of
creaturely freedom in order for it to be true. This assumption,
however, is problematic because it assumes libertarian freedom to be
false. The grounding objection, then, begs the question of
compatibilism.

The third Molinist response has been to compare contingent
propositions which refer to the actual future (or futurefactuals) with
contingent propositions which refer to counterfactual states of
affairs, specifically regarding statements which include how free
creatures will decide and would have decided. Those propositions which
refer to the actual future are either true or false now, even though
there is nothing in the present that can be pointed to as grounding
their truth. In a similar fashion, counterfactuals are either true or
false, even though there is nothing in the present that can be pointed
to as grounding their truth.

The fourth response by proponents of middle knowledge builds upon the
third and utilizes the standard possible worlds semantics. It may be
argued that the truth of futurefactuals of creaturely freedom are
grounded in the future occurrence or nonoccurrence of the event. In a
similar fashion, the truth of counterfactuals of creaturely freedom
may be grounded in the occurrence or nonoccurrence of the event in the
closest possible-but-not-actual world to the actual world. Thus, there
is something (an event) that may be pointed to as grounding the truth
of the statement.

The fifth and final response of Molinists has been to build upon the
suggestion that counterfactuals are brute facts about particular
individuals, by arguing that the truth of counterfactuals are grounded
in the individuals to which they refer as they exist in the
precreative mind of God as ideas. Since the grounding is in the
individual, contingency remains, yet since it is as the individual
exists in the mind of God as an idea, the problems associated with
grounding in the individual are avoided.

Although some of these responses may be deemed more successful than
others, and while some may be seen as more of a shifting of the burden
of proof than an answer to the specific objection, they do demonstrate
that the demand for grounding is somewhat unclear. However, it must
also be conceded that the efforts to answer the objection show that
some sort of idea of grounding is at least conceivable.
c. The Usefulness of Middle Knowledge

The third major objection to middle knowledge is similar to the second
in that it deals with the truth of counterfactuals of creaturely
freedom. Several forms of this argument have been proffered, but in
its most basic form, it claims that the priority inherent in the
Molinist system creates a problem for the truth of counterfactuals of
creaturely freedom—the verdict is that Molinist is either viciously
circular, or counterfactuals of creaturely freedom are not true soon
enough to aid God's creative decision.
i. Viciously Circular

Proponents of this objection point out that, according to Molinism,
the truth of counterfactuals of creaturely freedom must be prior to
God's creating activity because they inform His creative decision.
However, under the standard possible worlds analysis, which
counterfactuals are true is dependent upon which world is actual
(counterfactuals are true if they are true in the closest
possible-but-not-actual world to the actual world). Thus, which world
is actual (and presumably, how close all possible worlds are to it)
must be prior to God's knowledge of the true counterfactuals. But this
means that God's creative decision must be prior to God's creative
decision! Thus, middle knowledge is circular.
ii. Not True Soon Enough

A variation on this same argument ignores the possible worlds approach
to determining counterfactual truth and instead begins with the view
that a counterfactual is true by the action of the agent named in the
counterfactual. This, however, also leads to a problem because it
means that a truth regarding how the agent would act must be prior to
the agent's activity (presupposed in Molinism), but because the agent
is free, he could refrain from acting and thereby cause the
counterfactual to be false. Therefore, the truth of counterfactuals
must be "up in the air" until the agent acts. But this means that God
could not use counterfactuals of creaturely freedom to aid His
creative decision because they would not be true soon enough for Him
to use them (or if they were, the agents named could not refrain from
acting and therefore, would not be free).
iii. Molinist Responses

A whole host of answers have been presented by Molinists. The most
obvious response is to reject the possible worlds analysis of
counterfactuals—disallow the contention that the truth of
counterfactuals is somehow dependent upon which world is actual. Other
responses have included discussion of the use of "priority" or the
"depends on" relation in the two arguments. In both cases, it appears
that an equivocation has taken place. Last, both versions of the
argument betray an assumption of the incompatibility of libertarian
creaturely freedom and divine foreknowledge.
4. References and Further Readings
a. Books
Craig, William Lane. Divine Foreknowledge and Human Freedom: The
Coherence of Theism, Omniscience. New York: Brill, 1990.
Craig, William Lane. The Problem of Divine Foreknowledge and Future
Contingents from Aristotle to Suarez. New York: Brill, 1988.
Flint, Thomas P. Divine Providence: The Molinist Account.. Ithaca:
Cornell, 1998.
Hasker, William. God, Time, and Knowledge. Ithaca: Cornell, 1989.
Molina, Luis de. On Divine Foreknowledge: Part IV of the Concordia.
Translated by Alfred J. Freddoso. Ithaca: Cornell, 1988.
Plantinga, Alvin. The Nature of Necessity. Oxford: Clarendon, 1974.
b. Articles
Adams, Robert Merrihew. "An Anti-Molinist Argument" In Philosophical
Perspectives, vol. 5, Philosophy of Religion, ed. by James E.
Tomberlin, 343-53. Atascadero, CA: Ridgeview, 991.
Adams, Robert Merrihew. "Middle Knowledge and the Problem of Evil."
American Philosophical Quarterly 14:2 (April 1977): 109-17.
Hasker, William. "Middle Knowledge: A Refutation Revisited." Faith and
Philosophy 12:2 (April 1995): 223-36.
Hasker, William. "A New Anti-Molinist Argument." Religious Studies
35:3 (September 1999): 291-97.