The Nature of Necessity (Clarendon Library of Logic and Philosophy) Revised ed. Edition

Plantinga's Nature of Necessity is a philosophical masterpiece. Although there are a number of good books in analytic philosophy dealing with modality (the concepts of necessity and possibility), this one is of sufficient clarity and breadth that even non-philosophers will benefit from it.
Modal logic may seem like a fairly arcane subject to outsiders, but this book exhibits both its intrinsic interest and its general importance. If you think there are good and bad arguments, conclusions that follow from some premises but not others, then you ought to be concerned with modal logic. If you're interested in the problem of evil and the ontological argument for the existence of God, you should read this book.
The Nature of Necessity has the added virtue that it maps most peoples' modal intuitions quite well (unlike some modal theories). Perhaps it is for this reason that certain philosophers treat the book a bit snippishly. I've read the book a half a dozen times; and I'll probably read it a few more times before it's all said and done.

This is STILL Alvin Plantinga's most impressive book to date.

A philosophical masterpiece that excels in modal logic.

Plantinga does a great job with his version of the Ontological Argument. In perfect being theology, God is defined as "A Maximally Great Being" which means that God possesses all great-making, properties such as love, knowledge, and power, and possesses each in a maximal way.

Alvin Plantinga swings around Kant's object by showing how necessity is a property, and that Existence is not. Necessity does not entail existence. Necessity just means that if something exists, it exists in all possible worlds. Numbers have this property.

It is perfectly within the laws of modal logic for a property (which is not a perfection) to entail its negation.

While the Ontological Argument from Anselm has been restored by the likes of Stephen T Davis, now it clearly shows that the Ontological Argument is indeed the most powerful argument for God's existence. While the layman will have a lot of trouble understanding why, this does nothing to the argument itself.

Robert Maydole speaks about this book a lot in his writings of the Modal Perfection Argument, and rightly so. This book should is NECESSARY for everyone who is into philosophical theology.

Perhaps Peter van Inwagen put it best when he called this book a "treasure trove." Plantinga's _The Nature of Necessity_ contains deep and sophisticated work on some of most important and interesting issues in metaphysics: de re modality, the nature of essences and possible worlds, nonexistent objects, and the Ontological Argument. As far as this reviewer is concerned, Plantinga's work stands as one of the greatest works of metaphysics of *all time*. I cannot recommend it highly enough

Alvin Plantinga employs Quantified Modal Logic to provide insights into the Ontological Argument, the Problem of Evil and other problems in contemporary philosophical theology. A difficult book, but written with enormous clarity, power and wit. This is one of the best books I've ever read on any subject whatever

Plantinga's aim at the outset of this book is to defend the notion of de re (of objects) necessity against those (most notably Quine) who contend that all necessity is de dicto (of words). His strategy is not unlike that of his apologetics-style work in philosophy of religion such as _Warranted Christian Belief_ (25 years later!) in that he takes the more limited tack of meeting opposing arguments rather than positively establishing his own considered position. As in _WCB_, in _NN_ it is the de jure question of "is this not on all fours" rather than the de facto "is it true".

In the matter of Christian faith, this is a more or less fruitful and appropriate _philosophical_ route to take (since the de facto question in this case would be one that properly goes beyond human reason and philosophy), but in the case of this book it makes for an incomplete study, to my mind, of a topic that is philosophically important through-and-through. Plantinga gives no clue as to how we would actually _find out_ what the essential and what the accidental properties of a thing are, and the ongoing implicit assumption at work seems to be that our untutored intuitions are entirely reliable in this capacity. Plantinga's own approach does nothing to stave off any suspicions that his own procedure for picking out some properties as essential and other as accidental is any less "invidious" than Quine thought. For example, the favored example of an accidental property is Socrates as "snubnosed," but how is this to be played out? Assuming Socrates' snubnosedness is hereditary and not the result of an unfortunate encounter with a wall, it must be taken to be possible that Socrates' genetic makeup be different than it was. If that is granted (instead of saying, as I would, that counterfactual genetic difference in Socrates would have made for a person other than Socrates himself), then there's no bar to almost any feature of Socrates one would care to name coming out accidental, except the stipulation that he be "Socrates" (the referent of the proper name, in actual fact). Indeed, Plantinga actually takes seriously and even countenances the possibility of a reptilian Socrates! (Presumably, Plantinga would take the "conceivability" of Socrates as an alligator to be an argument for dualism--to anyone who thinks that, I direct you straight to Mark Johnston's "Human Beings"--but I'm getting off topic.)

That said, there is a lot of valuable work done here on the structure of modality de dicto and de re, from Plantinga's "kernel function" of expressing de re modal ascriptions in terms of the de dicto, through the nature of essence, worlds, "books," and so forth. One interesting quirk is that Plantinga seems to think the accessibility relation has some heuristic value for describing epistemic relations, but has no objective reality. This is a bit contentious, really, and he does not acknowledge other views on the subject. For that matter, this book is not at all a treatise on modal logic per se: you'll get no explorations of the various systems, S4, S5, etc., and their metaphysical implications to the system presented here. There are a lot of good points made about David Lewis's counterpart theory (the one rival to the "received" modal metaphysics Plantinga expounds on here), though, and some devastating criticisms of it on semantic grounds, especially.

The last few chapters see an application of the foregoing to some important topics in philosophical theology, and the results are a valuable resource for students of these topics. Plantinga's exploration of versions of the Ontological Argument I found especially interesting. The appendix examines, in somewhat greater detail than in the body of the book, various views on de re modality, and it's helpful to those who may want to look at the issue carefully.

This is one of the more difficult and technical philosophy works that I've read, but I found it (yes, you guessed it) valuable and helpful.

Plantinga always amazes me with both the subtlety and clarity of his thought. His application of abstract logical theory to traditional philisophical problems is inspired and inspiring, opening up some new avenues of thought in places we believed too travel-worn to bother with