The ontological argument for the existence of God has been a constant in the philosophy of religion since its first formulation by Anselm of Canterbury in the 11th century. In the 17th century, it was revived by Ren Descartes, and ever since has been a subject of dispute and much debate among philosophers. Descartes formulated it as follows: "Premise 1: That which we clearly understand to belong to the true and immutable nature, or essence, or form of something, can be truly asserted of that thing. "Premise 2: But once we have made a sufficiently careful investigation into what God is, we clearly and distinctly understand that existence belongs to his true and immutable nature. Conclusion: Hence we can now truly assert of God that he does exits" In this interesting history of the argument, philosopher Kevin J. Harrelson shows that the defense of the ontological argument is more consistent and persuasive than has frequently been supposed. In addition to correcting many common misunderstandings about the argument, the author highlights what appears to be an irremovable tension between the conclusion and the explanation of the proof. Both the common objections to the argument and its historical development in early modern philosophy are explained in light of this tension.

Proving the existence of God is a perennial philosophical ambition. An armchair proof would be the jackpot. Ontological arguments promise as much. This Element studies the most famous ontological arguments from Anselm, Descartes, Plantinga, and others besides. While the verdict is that ontological arguments don't work, they get us entangled in fun philosophical puzzles, from philosophy of religion to philosophy of language, from metaphysics to ethics, and beyond.

In recent years, the ontological argument and theistic metaphysics have been criticised by philosophers working in both the analytic and continental traditions. Responses to these criticisms have primarily come from philosophers who make use of the traditional, and problematic, concept of God. In this volume, Daniel A. Dombrowski defends the ontological argument against its contemporary critics, but he does so by using a neoclassical or process concept of God, thereby strengthening the case for a contemporary theistic metaphysics. Relying on the thought of Charles Hartshorne, he builds on Hartshorne's crucial distinction between divine existence and divine actuality, which enables neoclassical defenders of the ontological argument to avoid the familiar criticism that the argument moves illegitimately from an abstract concept to concrete reality. His argument, thus, avoids the problems inherent in the traditional concept of God as static.

This book is a unique contribution to the philosophy of religion. It offers a comprehensive discussion of one of the most famous arguments for the existence of God: the ontological argument. The author provides and analyzes a critical taxonomy of those versions of the argument that have been advanced in recent philosophical literature, as well as of those historically important versions found in the work of St. Anselm, Descartes, Leibniz, Hegel and others.

The book Ontological Proofs Today, apart from the introduction, consists of six parts. Part II comprises papers each of which pertains either to historical ontological arguments, or to some other, rather new, ontological arguments, but what makes them stand out from the other papers in this volume, is the fact that they all treat of the omniscience or the omnipotence of God. Part III includes papers which introduce new ontological arguments for the existence of God, without referring to omniscience and omnipotence as the transparent attributes of God. The issue of the type of necessity with which ontological proofs work or may work is raised in the articles of Part IV. In Part V the semantics for some ontological proofs are defined. Part VI consists of papers which, although quite different from each other in terms of content, all explore some ontological issues, and formal ontology may be considered the link between them. Part VII comprises two articles, by R. E. Maydole and G. Oppy, mutually controversial and different in their assessment of some ontological proofs.

Some commentators claim that Anselm’s writings contain a second independent “modal ontological argument” for God’s existence. A. D. Smith contends that although there is a second a priori argument in Anselm, it is not the modal argument. This “other argument” bears a striking resemblance to one that Duns Scotus would later employ.