In a book that will appeal to a general audience as well as philosophers of religion, a leading metaphysician tackles fundamental theological problems in a lucid and engaging manner. Peter van Inwagen begins with a provocative new introduction exploring the question of whether a philosopher such as himself is qualified to address theological matters. The chapters that follow take up the central problem of evil in a world created and sustained by God.

In this article I object to Le Poidevin's contention that relative identity is beset with an infinite metaphysical regress. I argue, first, that since Le Poidevin's regress argument presupposes a direct theory of reference, it does not apply to accounts of relative identity which reject this account of reference. I argue, second, that Le Poidevin's regress is not inevitable for one who accepts a direct account of reference, since it does not apply to the formal logic of relative identity which (...) van Inwagen uses to articulate and defend the mysteries of the Trinity and the Incarnation. (shrink)

I EXPLORE ONE WAY IN WHICH THE THEORY OF RELATIVE IDENTITY (DEVELOPED ALONG LINES SUGGESTED BY GEACH’S WRITINGS) CAN BE USED TO UNDERSTAND THE WAY LANGUAGE FUNCTIONS IN TRINITARIAN DOCTRINE. THIS INCLUDES A DISCUSSION OF REDUPLICATIVE PROPOSITIONS.

The Christian doctrine of the Trinity poses a serious philosophical problem. On the one hand, it seems to imply that there is exactly one divine being; on the other hand, it seems to imply that there are three. There is another well-known philosophical problem that presents us with a similar sort of tension: the problem of material constitution. We argue in this paper that a relatively neglected solution to the problem of material constitution can be developed into a novel solution (...) to the problem of the Trinity. (shrink)

P. T. Geach, notoriously, holds the Relative Identity Thesis, according to which a meaningful judgment of identity is always, implicitly or explicitly, relative to some general term. ‘The same’ is a fragmentary expression, and has no significance unless we say or mean ‘the same X’, where ‘X’ represents a general term (what Frege calls a Begriffswort or Begriffsausdruck). (P. T. Geach, Mental Acts (London: Routledge and Kegan Paul, 1957), p. 69. I maintain that it makes no sense to judge whether (...) things are ‘the same’, or remain ‘the same’, unless we add or understand some general term - ‘the same F’. (P. T. Geach, Reference and Generality, third Edition (Ithaca, N.Y.: Cornell University Press, 1980), pp. 63f. I am arguing for the thesis that identity is relative. When one says ‘x is identical with y’, this, I hold, is an incomplete expression; it is short for ‘x is the same A as y’, where ‘A’ represents some count noun understood from the context of utterance - or else, it is just a vague expression of a half-formed thought. (P. T. Geach, ‘Identity,’ Review of Metaphysics 21 (1967-8), p. 3.) One of the ways Geach seeks to support this is by tying it to the well nigh universally admired Fregean thesis about cardinality. (shrink)

What is it for there to be a God, and what reason is there for supposing him to conform to the claims of Christian doctrine? In this pivotal volume of his tetralogy, Richard Swinburne builds a rigorous metaphysical system for describing the world, and applies this to assessing the worth of the Christian tenets of the Trinity and the Incarnation. Part I is dedicated to analyzing the categories needed to address accounts of the divine nature--substance, cause, time, and necessity. Part (...) II begins by setting out, in terms of these categories, the fundamental doctrine of Western religions--that there is a God. After pointing out some of the different ways in which this doctrine can be developed, Swinburne spells out the simplest possible account of divine nature. He then goes on to clarify the implications of this account for the specifically Christian doctrines of the Trinity (that God is "three persons in one substance") and of the Incarnation (that God became incarnate in Jesus Christ). Swinburne finds that there are good reasons to believe the Christian additions to the core Western idea of God. The Christian God builds upon Swinburne's acclaimed previous work to form a self-contained text which will no doubt become a classic in the philosophy of religion. (shrink)

The doctrine of the Trinity maintains that there are exactly three divine Persons (Father, Son, and Holy Spirit) but only one God. The philosophical problem raised by this doctrine is well known. On the one hand, the doctrine seems clearly to imply that the divine Persons are numerically distinct. How else could they be ’three’ rather than one? On the other hand, it seems to imply that Father, Son, and Holy Spirit are identical. If each Person is divine, how else (...) could there be exactly ’one’ God? But the divine Persons can’t be both distinct and identical. Thus, the doctrine appears to be incoherent. Some try to solve this problem by appeal to the view that identity is sortal-relative. In this paper, I argue that this strategy is unsuccessful as a stand-alone solution to the problem of the Trinity. (shrink)

This paper is the first part of an exploration into the logical properties of relative identity. After providing the semantic grounds for various monadic logics of relative identity, I define the minimal system and its nine extensions. It is suggested that despite their purely formal origin at least some of them may contain nontrivial philosophical insights. All logics are axiomatized by means of sound and complete sequent calculi. I show their affinities with existing formalizations.

This article defends my claim, first presented in "identity and trinity," "journal of religion" (1978), that the doctrine of the trinity is consistent. drawing upon tertullian's defense of the doctrine in "adversus praxean", i argue that the logic of the trinity is similar to the logic of emperorship. at various times, two persons, for example, diocletian and maximian, were the same emperor of the roman empire, just as three persons are the same god.

One way of understanding the reduplicative formula "Christ is, ’qua’ God, omniscient, but ’qua’ man, limited in knowledge" is to take the occurrences of the ‘qua‘ locution as picking out different parts of Christ: a divine part and a human part. But this view of Christ as a composite being runs into paradox when combined with the orthodox understanding of the Incarnation, according to which Christ is identical to the second person of the Trinity. In response, we have to choose (...) between modifying the orthodox understanding, adopting a philosophically and theologically contentious perdurantist account of persistence through time, or rejecting altogether the idea of the composite Christ. (shrink)

One way of understanding the reduplicative formula ‘Christ is, qua God, omniscient, but qua man, limited in knowledge’ is to take the occurrences of the ‘ qua ’ locution as picking out different parts of Christ: a divine part and a human part. But this view of Christ as a composite being runs into paradox when combined with the orthodox understanding of the Incarnation, according to which Christ is identical to the second person of the Trinity. In response, we have (...) to choose between modifying the orthodox understanding, adopting a philosophically and theologically contentious perdurantist account of persistence through time, or rejecting altogether the idea of the composite Christ. (shrink)

This paper is a reflection on two ontological analogies that have played a role in discussion about the Trinity---the Modalist and Social analogies. I argue that the Modal analogy commits one to a view of the divine persons that comports poorly with Scripture. I then consider two arguments to the effect that the doctrine of the Trinity commits one to tritheism. I argue that the Social analogy contains better resources for handling these arguments than the more traditional position, which involves (...) denying that the divine persons are substances. (shrink)

Brian Leftow has proposed a “Latin” doctrine of the Trinity according to which “the Father just is God,” and so also for the Son and the Spirit. I argue that Leftow’s doctrine as he presents it really does have the consequence that Father, Son, and Spirit are all identical, a consequence that is inconsistent with orthodox Trinitarianism. A fairly minor modification would enable Leftow to avoid this untoward consequence. But the doctrine as modified will still retain a strongly modalistic flavor: (...) it implies, among other things, that the prayers of Jesus in the Gospels are instances of God-as-Son praying to himself, namely to God-as-Father. If this is found unacceptable, Leftow may have been too quick to dismiss Social Trinitarianism. (shrink)

The author attacks the view that identity, Like largeness, Is a relative relation. The primary advocate of the view that identity is relative is p.T. Geach. It is argued that geach has not shown that the failure of the identity of indiscernibles principle, As a truth of logic, Forces us to stop taking indiscernibility within particular formal theories or languages as a sufficient condition for identity. The author also argues that the whole notion of relative identity, As explicated by geach, (...) Is very probably incoherent. (shrink)

Quasi-set theory has been proposed as a means of handling collections of indiscernible objects. Although the most direct application of the theory is quantum physics, it can be seen per se as a non-classical logic (a non-reflexive logic). In this paper we revise and correct some aspects of quasi-set theory as presented in [12], so as to avoid some misunderstandings and possible misinterpretations about the results achieved by the theory. Some further ideas with regard to quantum field theory are also (...) advanced in this paper. (shrink)

Classical Christian orthodoxy insists that God is Triune: there is only one God, but there are three divine Persons — Father, Son, and Holy Spirit — who are somehow of one substance with one another. But what does this doctrine mean? How can we coherently believe that there is only one God if we also believe that there are three divine Persons? This problem, sometimes called the ‘threeness-oneness problem’ or the ‘logical problem of the Trinity’, is the focus of this (...) interdisciplinary volume. It includes a selection of recent philosophical work on this topic, accompanied by a variety of essays by philosophers and theologians to further the discussion. The book is divided into four parts, the first three dealing in turn with the three most prominent models for understanding the relations between the Persons of the Trinity: Social Trinitarianism, Latin Trinitarianism, and Relative Trinitarianism. Each section includes essays by both proponents and critics of the relevant model. The volume concludes with a section containing essays by theologians reflecting on the current state of the debate. (shrink)

The authors of this lively and thorough introduction to philosophy from a Christian perspective introduce you to the principal subdisciplines of philosophy, including epistemology, metaphysics, philosophy of science, ethics and philosophy ...

Steven French and Decio Krause examine the metaphysical foundations of quantum physics. They draw together historical, logical, and philosophical perspectives on the fundamental nature of quantum particles and offer new insights on a range of important issues. Focusing on the concepts of identity and individuality, the authors explore two alternative metaphysical views; according to one, quantum particles are no different from books, tables, and people in this respect; according to the other, they most certainly are. Each view comes with certain (...) costs attached and after describing their origins in the history of quantum theory, the authors carefully consider whether these costs are worth bearing. Recent contributions to these discussions are analyzed in detail and the authors present their own original perspective on the issues. The final chapter suggests how this perspective can be taken forward in the context of quantum field theory. (shrink)

Absolute identity seems at first sight to be presupposed in the branch of formal logic called identity theory. Classical identity theory may be obtained by adjoining a single schema to ordinary quantification theory.