Alexander R. Pruss

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.

Adhering to the traditional concept of omniscience lands Gale in the incoherence Grim’s Cantorian arguments reveal in talk of “all propositions.” By constructing variants and extensions of Grim’s arguments, I explain why various ways out of the incoherence are unacceptable, why theists would do better to adopt a certain revisionary concept of omniscience, and why the Cantorian troubles are so deep as to be troubles as well for Gale’s Weak PSR. I conclude with some brief reflections on method, suggesting that we pursue the full implications of Gale’s own revisionary remarks and replace his method of analytic argumentation with non-analytic revisionary theory-construction.

Some, notably Peter van Inwagen, in order to avoid problems with free will and omniscience, replace the condition that an omniscient being knows all true propositions with a version of the apparently weaker condition that an omniscient being knows all knowable true propositions. I shall show that the apparently weaker condition, when conjoined with uncontroversial claims and the logical closure of an omniscient being's knowledge, still yields the claim that an omniscient being knows all true propositions.

          Despite the fact that the strength of argument is clearly on the pro-life side—nobody except a handful of academics would question the grave wrongness of abortion were pregnancy never inconvenient—somehow ordinary intelligent people, like our students, often remain unconvinced. There are many reasons for this, of course. For instance, a number of students have had their children aborted while many know others who have had abortions, and one does not want to condemn oneself or oneÂ’s friends. I am a philosopher, however, and so I will be interested in intellectual reasons, even though these subjective psychological ones are almost surely more important. Specifically, I will be interested in the fact that the ordinary person subscribes to a number of erroneous big-picture ethical beliefs, each of which, to a different degree, does something to block access to the pro-life arguments. I will not talk about all such erroneous beliefs and I would be grateful in the discussion for more examples.           I will talk about eight errors I have identified, largely through teaching. For each one, I will identify the error, show how it impacts the pro-life message and explain why it is tempting to most of us —there is, after all, something right about five of the errors. For each of these errors is one that we might ourselves be tempted by on occasion. I will then suggest some ways of refuting the error. In some cases, the mere identification of the error should do the trick, as these erroneous beliefs are often not explicitly identified by our interlocutors. My suggested refutations will not always be phrased in the way in which I would phrase them for didactic effectiveness: in this talk, I am mainly trying to convey ideas.

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.

As Mark Murphy has recently shown, standard justifications of universal divine authority are insufficient. [1] By “divine authority” I shall mean the doctrine that obedience is morally owed to God by all. God would not give us a command that we did not have a reason to act in accordance with, Murphy argues, but it does not follow that we would be obliged, much less morally obliged, to have the fact of God’s having commanded the action be among our practical reasons for the action. We might, for instance, think that what God has commanded us is prudentially the best policy for us or that it is the best possible evidence for what is on independent grounds morally obligatory.

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.

The Principle of Sufficient Reason says that all contingent facts must have explanation. In this 2006 volume, which was the first on the topic in the English language in nearly half a century, Alexander Pruss examines the substantive philosophical issues raised by the Principle Reason. Discussing various forms of the PSR and selected historical episodes, from Parmenides, Leibnez, and Hume, Pruss defends the claim that every true contingent proposition must have an explanation against major objections, including Hume's imaginability argument and Peter van Inwagen's argument that the PSR entails modal fatalism. Pruss also provides a number of positive arguments for the PSR, based on considerations as different as the metaphysics of existence, counterfactuals and modality, negative explanations, and the everyday applicability of the PSR. Moreover, Pruss shows how the PSR would advance the discussion in a number of disparate fields, including meta-ethics and the philosophy of mathematics.