The popularity of ideas, as that of other things, ebbs and flows. This is true even in philosophy, where the intention is for reason to prevail. In philosophy there is intense clarification of concepts and their implications, and deployment of arguments in which these concepts figure. Arguments may be proved to be invalid, or to be based on ideas that are dubious because confused. When I was younger, Logical Positivism and its effects prevailed. It has the characteristic thesis that unless a proposition could be verified or falsified (or is in principle verifiable and falsifiable) by sense experience, it was cognitively (i.e., literally) meaningless. It was counter-argued that by that standard many scientific claims are unverifiable or unfalsifiable, and that scientific laws appear to be verifiable or falsifiable in principle. Many other propositions were unfalsifiable yet meaningful. Why then not theological propositions? For a while the arguments go to and fro, some being convinced that logical positivism is indefensible, others that it is defensible, and many in between. And then what usually happens is that a tiredness settles over the academic community as the arguments are rehearsed and revisited and as little new light emerges. People look for other things to argue about. The wheel turns.

In the 1970's Alvin Plantinga defended and developed the free will defense against the charge that it is inconsistent to suppose that there is evil in a universe created by an all-good, all-powerful God. Plantinga's adherence to a libertarian account of human freedom is crucial to this argument. It is fair to say that he elaborated this argument with a sophistication that is without parallel in the modern literature. In what may be called the second phase of this work, he employed the newly developed semantics of modal logic to argue that God can know the counterfactuals of freedom, propositions such as 'If A were placed in circumstances C, he would freely choose to X rather than Y'. He knows what would happen in the future since he knows what A would freely do if placed in circumstances C. God can then 'weakly actualise' C in some circumstances which best suit his purposes knowing that, say, in those circumstances A will choose X. (For details, see Plantinga God, Freedom and Evil, pp. 49-50.)

Little did Plantinga know (until it was pointed out to him by the likes of Anthony Kenny and Bob Adams) that he had thereby reinvented the Molinist doctrine of middle knowledge: that besides God's natural knowledge and his free knowledge, he possesses middle knowledge, knowledge of the counterfactuals of human freedom. By actualizing a possible world in which this state of affairs is true, God can ensure that creaturely freedom is preserved as well as his immaculate knowledge of the future free actions of his creatures. Bingo!

Plantinga's proposal precipitated an avalanche of discussion on Molinism. Parts of Molina's Concordia were translated into English for the first time, and several philosophical theologians became avowed Molinists, applying the insights not only to the problem of evil, but to the incarnation, providence, prayer, heaven and hell, perseverance in grace, and so on. The main practitioners here are Tom Flint (Divine Providence and innumerable articles) and Bill Craig (The Only Wise God and equally innumerable articles-and other books). The likes of Flint and Craig were challenged, among others, by William Hasker, for how God might know the future free actions of his creatures and how they be brought about is beside the point, he being an Open Theist. Some of the articles by these and others have been collected in Middle Knowledge: Theory and Applications(ed. William Hasker, David Basinger, and Eef Dekker; Frankfurt am Main, Peter Lang, 2000).

Now here is another collection, welcome of course, but several features about it suggest that, after a surge of interest, the Molinist tide is ebbing. No one now gets excited over the 'grounding objection' to Molinism, the objection that God cannot have knowledge of future free actions unless he has evidence, and what could that evidence be, given libertarian freedom? A number of contributions review and summarise the course of arguments in 'Molinist studies' without offering any new arguments, while others go to topics at the margin, such as theodicy (and hard determinism). This also suggests that the tide of interest and philosophical argument and counter-argument is retreating and that Molinism will drop in the league table of interest to be replaced by the next issue to attract interest.

In his helpful introduction to this new collection, Ken Perszyk not only provides interesting historical background; he restates the distinction between the theory of middle knowledge, its perspicuous statement, and the discussion of resources that may be called upon to overcoming objections to its deployment, on the one hand, and also its application to grace, predestination and free will, and other theological areas. The question 'Can it fly?' raises one set of questions. If so, 'Where can it fly to?' raises another, though it would be misleading to suppose that those who are interested in this second question wait patiently until the first question is settled, if it can be settled to general satisfaction. And this is fair enough because the second question can in any case be raised hypothetically: if Molinism were to be theoretically satisfactory, where could it be deployed?

Among the chief theoretical questions are questions about the counterfactuals of freedom, whether there can be any that are true, and our old friend the 'grounding objection'. This is featured here in two summary discussions, Hasker, 'The (Non)-Existence of Molinist Counterfactuals', and Tom Flint in 'Whence and Whither the Molinist Debate: A Reply to Hasker', and the latest rounds of the debate. A second kind of theoretical objection, that is concerned with bringing about counterfactuals of freedom, making them true by what we do, is also discussed. This features Hasker again, and Flint and Trenton Merricks. And there is discussion about whether there can be true counterfactuals of freedom prior to God's decree of them. Objections along this line go back to J.L. Mackie. The remaining papers are by Dean Zimmerman and Merricks, Edwin Mares and Ken Perszyk, Edward Wierenga, William Lane Craig and Greg Restall. Those by Derk Pereboom, Hugh McCann, and perhaps John Fischer on determinism and providence, the free will defense, and on what Molinism does and does not imply stand apart from the main lines of argument. Some of the papers are quite technical, because a further reason for discussing Molinism is a philosophical interest in conditionals and modality. All these discussions have this in common: an overriding concern to safeguard human libertarian freedom. This needs to be borne in mind when we read, for example, that middle knowledge provides 'the reconciliation of divine sovereignty and human freedom' (William Lane Craig, p.210), for Craig means divine sovereignty in the Arminian sense.

As regards so-called 'applied' Molinism, the satisfactoriness of these discussions depends in part on what one regards as a satisfactory Christian doctrine. But Molinism cannot be allowed to determine the contours of a Christian doctrine or how it is to be formulated.

Harking back to the objection to there being true counterfactuals of freedom prior to God's decreeing of them, this is one of the few places at which contemporary discussion of Molinism connects with the original Reformed objections to Middle Knowledge. Theologians such as William Twisse and Samuel Rutherford were not so much interested in whether Molinism was internally satisfactory as in cutting it off at the root because they could not conceive of any counterfactuals of creaturely freedom being true that were not first decreed by God, and true because of this, and so part of his free knowledge. So they argued ad hominem against Molinism by denying the very idea of middle knowledge. Their answer to the current 'grounding' objection would be that what grounds the truth is not evidence that exists apart from the decree of God, but that decree. So the idea of middle knowledge, some category between the natural and free knowledge of God, is inadmissible. How could it be known to God that in circumstances C, A will freely do P other than by being unconditionally decreed by him, and so being an aspect of the divine free knowledge? If God cannot know this, it cannot be true. (Do I hear you say that there is some equivocation in these debates in the use of 'knowledge' in phrases such as 'middle knowledge' and 'God's free knowledge'? Indeed there may be, but the fact goes largely unnoticed.)

This is why those philosophers with Calvinistic convictions do not figure very prominently in current debates about Molinism, which is (as a rule) defended by those who wish to retain a traditional understanding of the scope of divine omniscience, and covers future libertarian actions, and is attacked by those who uphold libertarianism and who let go of the traditional view of omniscience. So viewed theologically, it is a debate within the libertarian guild, discussed without any reference to the necessity and scope of the divine decrees, and it excludes such as Hugh McCann, who upholds absolute divine sovereignty and libertarian free will. To admit a Calvinist to the party would be a conversation-stopper or at least a conversation-changer, in which the Calvinist would do his best to show how unfair it is to characterize his position as theological fatalism and human beings as puppets or machines run along fatalistic lines. (The 'fates' are in fact the purposes of God our creator who has given us life and who governs what he has created towards specific ends in accordance with his good and wise purposes.) He may in turn attempt to change the conversation by name-calling, perhaps by calling the God of Molinism the 'Demiurge' (p.11n22) and Open theist theologians as 'Socinians'. But nothing is to be gained by name-calling.

For the Reformed who debated Molinism in the seventeenth century, God's knowledge of what takes place in his creation, whatever else it is, is knowledge of what he will decree. So the idea that there are states of affairs, including the counterfactuals of creaturely freedom, which are distinct from the divine mind and which are made true or false only by acts of creaturely freedom which God abets by supporting and enabling but which he does not foreknow, is quite unacceptable. Theologians such as Bruch Ware, who finds a place for 'Reformed Molinism' (God's Greater Glory, pp.110-12), are an odd and an inexplicable exception.