Alexander R. Pruss

One of the problems that Bayesian regularity, the thesis that all contingent propositions should be given probabilities strictly between zero and one, faces is the possibility of random processes that randomly and uniformly choose a number between zero and one. According to classical probability theory, the probability that such a process picks a particular number in the range is zero, but of course any number in the range can indeed be picked. There is a solution to this particular problem on the books: a measure that assigns the same infinitesimal probability to each number between zero and one. I will show that such a measure, while mathematically interesting, is pathological for use in confirmation theory, for the same reason that a measure that assigns an infinitesimal probability to each possible outcome in a countably infinite lottery is pathological. The pathology is that one can force someone to assign a probability within an infinitesimal of one to an unlikely event

A recombinationist like the earlier Armstrong (1989) claims that logically possible worlds are recombinations of items found in the actual world, with some items reduplicated if need be and others deleted. An immediate consequence of this is that if an alien property is a property that could only be defined in terms of fundamental properties that are actually uninstantiated, then it is logically impossible that an alien property be instantiated as no recombination of the items in the actual world can yield a world with an entity having such a property. Recombinationism immediately implies that S5 is false. To see this, suppose for simplicity, as I will throughout this paper, that electric charge is a fundamental property--otherwise, a different example would have to be used. Then, let w be a possible world lacking any charged objects. At w, then, it is true that it is logically impossible that there be a charged particle since no recombination of the entities in w yields a charged particle. Therefore, contrary to S5, what is possible at w differs from what is possible at the actual world, since charged particles are actual and hence logically possible at the actual world. While this argument may make one sceptical of recombinationism, the recombinationist will say that it is not surprising that if we follow out the Aristotelian intuition that possibility is to be grounded in actually existing entities, then what is possible will depend on what is actual. Henceforth I will no longer assume S5, and so logical possibilities will have to be relativized to worlds if recombinationism is true: it is logically possible at the actual world for charged particles to exist, but at a world at which there are no charged particles it is logically impossible for charged particles to exist...

There is an important sense in which one can be sure without being certain, i.e., without assigning unit probability. I will offer an explication of this sense of sureness, connecting it with the level of credence that a rational agent would need to have to be confident that she won’t ever lose her confidence. A simple formal result then gives us an explicit formula connecting the threshold α for credence needed for confidence with the threshold needed for being sure: one needs 1−(1−α) to be sure. I then suggest that stepping between α and 1−(1−α) gives a procedure that generates an interesting hierarchy of credential thresholds.

Popper functions allow one to take conditional probabilities as primitive instead of deriving them from unconditional probabilities via the ratio formula P=P/P. A major advantage of this approach is it allows one to condition on events of zero probability. I will show that under plausible symmetry conditions, Popper functions often fail to do what they were supposed to do. For instance, suppose we want to define the Popper function for an isometrically invariant case in two dimensions and hence require the Popper function to be rotationally invariant and defined on pairs of sets from some algebra that contains at least all countable subsets. Then it turns out that the Popper function trivializes for all finite sets: P=1 for all A ) if B is finite. Likewise, Popper functions invariant under all sequence reflections can’t be defined in a way that models a bidirectionally infinite sequence of independent coin tosses

Animalism is the view that we are animals and, thus, satisfy the criteria of identity proper to animals. This is highly plausible, for instance because it accepts at face value what appears to be the obvious facts that we are mammals—after all, we have the hair, the inner ear bones and the milk that mammals do—and that being a mammal is a way of being an animal. On the main opposing view, one has to hold that associated with each of us there are two entities: a person and an animal, of which we are only one, and this seems needlessly..

Substantive theories of diachronic identity have been offered for different kinds of entities. The kind of entity whose diachronic identity has received the most attention in the literature is person, where such theories as the psychological theory, the body theory, the soul theory, and animalism have been defended. At the same time, Wittgenstein's remark that ?to say of two things that they are identical is nonsense, and to say of one thing that it is identical with itself is to say nothing at all? suggests that the idea of further analysing identity is mistaken at root. I shall offer a simple, deflationary theory that reduces diachronic identity to quantification, synchronic identity and existence at a spacetime location (or at a time, for non-spatial entities). On logical grounds, the theory is guaranteed to have no counterexamples. Because the theory is guaranteed to have no counterexamples, all the imaginative examples offered as intuitive support for theories of personal identity are going to be either incorrect or compatible with the theory. I shall argue that the deflationary theory is preferable on simplicity grounds to typical substantive theories, and that various problems that are commonly thought to concern diachronic identity are better seen as about something else

The production of a number of vaccines involves the use of cell-lines originally derived from fetuses directly aborted in the 1960s and 1970s. Such cell-lines, indeed sometimes the very same ones, are important to on-going research, including at Catholic institutions. The cells currently used are removed by a number of decades and by a significant number of cellular generations from the original cells. Moreover, the original cells extracted from the bodies of the aborted fetuses were transformed to produce the cell lines, since otherwise they would be incapable of the kind of culturing that is required.

We will give a new cosmological argument for the existence of a being who, although not proved to be the absolutely perfect God of the great Medieval theists, also is capable of playing the role in the lives of working theists of a being that is a suitable object of worship, adoration, love, respect, and obedience. Unlike the absolutely perfect God, the God whose necessary existence is established by our argument will not be shown to essentially have the divine perfections of omnipotence, omniscience, omnibenevolence, and sovereignty. Furthermore, it is not even shown that he is contingently omnipotent and omniscient, just powerful and intelligent enough to be the supernatural designer-creator of the exceedingly complex and wondrous cosmos that in fact..

The cosmos is filled with evil that seemingly has no redeeming value. Granted, some evils do lead to greater goods, sometimes goods that could not exist without the evils. Thus, the exercise of courage is a good that requires either an actual evil to stand firm in the face of or the illusion of an evil—and an illusion is a kind of evil, too. But many evils appear to serve no such purpose. Philosophers call an evil that a supremely good God would have insufficient reason to permit to exist a gratuitous evil. A particularly powerful form of the argument from evil against the existence of the God of Western monotheism is, thus, that there..

Louis Pojman has argued that Christian faith does not entail belief, or even assigning a probability of 1/2 to the claims of Christianity. However, this conclusion fails in many cases because of its ethical consequences. A Christian is committed by his faith to acting in accordance with Christian teaching. However, there are circumstances when it is morally impermissible to act in accordance to beliefs to which one assigns epistemic probability smaller than 1/2, namely when the action is prohibited by ethical claims that one takes to be more probable. It is argued that in most cases such considerations preclude a person who assigns a probability of less 1/2 from being both committed both to Christianity and to the moral life. Matters are particularly clear in the paradigmatic faith-action of Abraham’s sacrifice of Isaac: this action would clearly be immoral if Abraham assigned a probability less than 1/2, or in fact any probability not very close to 1, to the existence of God. A moral version of Pascal’s wager is also discussed.

There is a long tradition of arguments for the existence of God. Early examples include Aristotle’s cosmological argument in Book Lambda of the Metaphysics, arguing that if there is change, there must be at least one unchanging and perfect being that originates all change, while the first chapter of Romans and chapter 13 of the Book of Wisdom insist that “from the greatness and the beauty of created things their original author, by analogy, is seen” (Wis. 13:5, NAB). This tradition continues, and indeed starting in the 1950s, analytic philosophy has seen an impressive resurgence of more and more careful formulations and criticisms of arguments for the existence of God. I shall show how the phenomenon of altruism yields a theistic argument. Some arguments for the existence of God proceed by pure reasoning alone and yield ontological arguments like Anselm’s, while others depend in part either on particular empirical claims (e.g., the argument from miracles or the argument from religious experience), or on general empirical claims, such as that there is motion, consciousness or life. The pattern of the arguments based on general claims is usually simple: (A) There is a general fact about reality, say that there is change or that there are complex organisms. (B) One argues that either the best or the only explanation is to be found in some state of affairs that includes the existence of a God-like being. And so (C) one concludes that a God-like being..

In simplified form, the argument that I am defending holds that the incompatibility of our freedom with determinism follows from the conjunction of (1) a plausible supervenience claim which says that whether a human agent is free depends only on what happens during the agent’s life and (2) a freedom-cancellation principle of Richard Gale which says that an agent is not free if all of her actions are intentionally brought about by another agent. Improved versions of (1) and (2) are also considered

This important philosophical reflection on love and sexuality from a broadly Christian perspective is aimed at philosophers, theologians, and educated Christian readers. Alexander R. Pruss focuses on foundational questions on the nature of romantic love and on controversial questions in sexual ethics on the basis of the fundamental idea that romantic love pursues union of two persons as one body. _One Body_ begins with an account, inspired by St. Thomas Aquinas, of the general nature of love as constituted by components of goodwill, appreciation, and unitiveness. Different forms of love, such as parental, collegial, filial, friendly, fraternal, or romantic, Pruss argues, differ primarily not in terms of goodwill or appreciation but in terms of the kind of union that is sought. Pruss examines romantic love as distinguished from other kinds of love by a focus on a particular kind of union, a deep union as one body achieved through the joint biological striving of the sort involved in reproduction. Taking the account of the union that romantic love seeks as a foundation, the book considers the nature of marriage and applies its account to controversial ethical questions, such as the connection between love, sex, and commitment and the moral issues involving contraception, same-sex activity, and reproductive technology. With philosophical rigor and sophistication, Pruss provides carefully argued answers to controversial questions in Christian sexual ethics. "This is a terrific—really quite extraordinary—work of scholarship. It is quite simply the best work on Christian sexual ethics that I have seen. It will become the text that anyone who ventures into the field will have to grapple with—a kind of touchstone. Moreover, it is filled with arguments with which even secular writers on sexual morality will have to engage and come to terms." —_Robert P. George, Princeton University __ "_One Body_ is an excellent piece of philosophical-theological reflection on the nature of sexuality and marriage. This book has the potential to become a standard go-to text for professors and students working on sex ethics issues, whether in philosophy or theology, both for the richness of its arguments, and the scope of its coverage of cases. " — Christopher Tollefsen, University of South Carolina_ "Alexander Pruss here develops sound and humane answers to the whole range of main questions about human sexual and reproductive choices. His principal argument for the key answers is very different from the one I have articulated over the past fifteen years. But his argumentation is at every point attractively direct, careful, energetic in framing and responding to objections, and admirably attentive to realities and the human goods at stake." —_John Finnis, University of Oxford _