Alexander R. Pruss:

Selected Papers and Essays

For a list of publications, please see my CV. I've also been blogging philosophically at and   A number of the papers here are works in progress.  Comments are welcome, especially on the works in progress.  Click on the title of a paper if you want to read the paper.

Quick links: [Metaphysics and logic] [Philosophy of religion and theology] [Ethics] [Mathematical papers]

Philosophical and theological papers

Metaphysics, philosophy of language, formal epistemology and logic

  • “Counterfactuals, Vagueness and God”.
  • “Popper functions, uniform distributions and infinite sequences of heads”, forthcoming in the Journal of Philosophical Logic.   I show that invariant full conditional probabilities are untenable in dimensions two and higher.
  • “Regular probability comparisons imply the Banach-Tarski Paradox”, forthcoming in Synthese.  I show that the existence of regular probability measures (hyperreal, conditional or comparative) imply the Banach-Tarski Paradox.
  • “Incompatibilism proved”, forthcoming in the Canadian Journal of Philosophy. I show that the transfer principle in the consequence argument for incompatibilism follows (given a plausible definition) from the rule of weakening for subjunctive conditionals.
  • “Infinitesimals are too small for countably infinite fair lotteries”, Synthese. Infinitesimals are too small to be the probability of winning a countably infinite fair lottery.
  • “Sincerely asserting what you do not believe”, Australasian Journal of Philosophy. Examples show that one can sincerely assert what one does not believe—in some odd situations.
  • “Infinite lotteries, perfectly thin darts and infinitesimals”, forthcoming in Thought. Using infinitesimals to model the results of dart throws and the like leads to serious problems.
  • "A Deflationary Theory of Diachronic Identity", Australasian Journal of Philosophy. I defend a theory of diachronic identity guaranteed to have no counterexamples and superior to substantive theories.
  • "Artificial Intelligence and Personal Identity", appeared in Faith and Philosophy. I argue that absurdities follow from the assumption that a robot is a person.
  • "Identity and the Copying of Minds". I argue against psychological theories of identity that claim that in cases where one's personality and memories are moved into the brain of another, we move with them. I am not entirely convinced by my arguments here, I must confess, but I think they deserve some thought.
  • "Freedom, Determinism and Gale's Principle."  I give an argument for incompatibilism on the basis of a plausible supervenience principle and a weakened version of Gale's principle that if all my actions were intentionally caused by another person, then none of my actions were free.
  • "Special Relativity and Endurantism."  I identify a fallacy in Hales and Johnson's argument that endurantism is incompatible with special relativity and argue that an improvement on their argument also does not succeed.
  • "Processes, Marks and Light-Spots."  I give a simple counterexample to Salmon's account of causal processes in terms of mark transmission.  The example has the advantage that not only does it appear to qualify as transmission of a mark under Salmon's definition of mark transmission, but it appears to actually be an instance of mark transmission.
  • "Animalism and Brains"I argue that it is possible for a human animal to survive the loss of all bodily parts other than the brain.
  • "B-Theory, Language and Ethics", Philosophy of Time Group Meeting, Eastern APA, 2006.
  • The Principle of Sufficient Reason: A Reassessment, Cambridge University Press, in 2006.  No longer available online, but can be purchased from
  • "Ex Nihilo Nihil Fit: Arguments New and Old for the Principle of Sufficient Reason", presented at the American Catholic Philosophical Association meeting, Cincinnati, November, 2002
  • "Comments on John Haldane's 'The Soul'", presented in Pittsburgh, April 5, 2003.  (Handout is also available.)
  • Possible Worlds: What They Are Good For and What They Are.  Doctoral Dissertation, University of Pittsburgh, 2001.
  • "The Actual and the Possible."  In Richard M. Gale (ed.), Blackwell Guide to Metaphysics, Oxford: Blackwell, 2002.  A discussion of two contemporary views of the nature of possibility and possible worlds, and a theistic alternative.  Includes a new version of the Third Way, and ethical objections to David Lewis's extreme modal realism.
  • "David Lewis's Counterfactual Arrow of Time."  Published in NousI argue that David Lewis's counterfactual account of the direction of time fails in a number of cases, and in other cases only succeeds because the cases are chosen by us in ways that cohere with our time-reversal-asymmetric concerns.
  • "The Subjunctive Conditional Law of Excluded Middle."  Work in progress.  This Law claims that for any pair of propositions p and q, it is true that were p to hold, q would hold or it is true that were p to hold, not-q would hold.  I show that given plausible suppositions the Law is false.
  • "The Cardinality Objection to David Lewis's Modal Realism."  Philosophical Studies 104 (2001) 167-176.  The collection of all possible worlds is too large to have cardinality and hence possible worlds cannot be existent concrete entities.
  • "What Are Aristotelian Forms?"  Early version of paper forthcoming in Analysis and Existence.  Prescinding from detailed exegesis of texts, what kind of an entity is an Aristotelian form?  Can the notion be made intelligible in a contemporary setting?  What would one be saying about the world by saying that there are Aristotelian forms?
  • "Recombination, Alien Properties and Laws of Nature"  A criticism of recombinationist theories of possibility, and an argument against views that utterly reject alien properties.
  • "Functionalism and Counting Minds."  Work in progressIn general there is no fact of the matter as to how many machines are computing any given program.  Since there plainly is a fact of the matter as to how many persons are conscious in a given way, it follows that being a conscious person is not simply a matter of being an appropriate computing system.
  • "Can Two Equal Infinity?  The Attributes of God in Spinoza."  Work in progress.  Spinoza's God has "infinite attributes", even though only Extension and Thought are mentioned explicitly?  I argue that Spinoza, given his commitment to the truthmaker principle that any true proposition is made true by something positive, can neither say nor deny that Extension and Thought are the only two attributes.  I end with a truthmaker-based ontological argument for the existence of God that might be of interest independently of Spinoza.
  • "Lewis's Semantics for Subjunctive Conditionals and Some Plausible Rules of Inference." [PDF] Forthcoming in SyntheseI show that on a plausible interpretation of the closeness relation between worlds, Lewis's account of subjunctive conditionals fails to support two obvious rules of inference concerning conjunctions of consequents or disjunctions of antecedents.  I offer a modification of Lewis's semantics that solves this problem, but note that some difficulty still remains.  I also characterize when the subjunctive conditional law of excluded middle holds.
  • "Causation and the Arrow of Time."  I argue that the direction of time probably supervenes on the directions of causal relations.

Philosophy of religion and theology


  • "Marriage is a Natural Kind", at Mid-West Society of Christian Philosophers conference, 2016
  • "Care and Union", talk for a workshop on the work of Nicholas Wolterstorff, Baylor University, 2009
  • "One Body: Reflections on Christian Sexual Ethics", talk at the University of St Thomas, Houston, TX, 2008
  • "Cooperation, Also With Evildoers", Society of Christian Philosophers Eastern Division Meeting, 2008
  • "Plans and their Accomplishment", Maritain Society Group Meeting, Eastern APA, 2006
  • "Cooperation with past evil and use of cell-lines derived from aborted fetuses."  I argue for a moderate position on which the use of such cell-lines has a presumption against it, but is not absolutely forbidden.  At the same time, I analyze why precisely there is such a presumption.  This analysis has interesting connections with the retributive theory of punishment.
  • "Love and Double Effect."  Presented at the Formation and Renewal Conference, Notre Dame University, October, 2003
  • "Eight Tempting Big-Picture Errors in Ethics."  Presented at the University Faculty for Life Conference, Georgetown University, May 31, 2003
  • "Kantian Maxims and Lying."  Work in progress.  Christine Korsgaard argued that Kant's first Categorical Imperative (CI) allows you to lie to people who try to deceive you about their intentions.  I argue that Korsgaard's argument rests on what appears to be a subtle misunderstanding of the nature of a Kantian maxim.
  • "Lying, Deception and Kant."  Work in progress.  A common objection to Kant is that his view prohibits lying under all circumstances.  But there is a distinction between lying and deception, and some forms of deception are clearly permissible.  A more serious objection to Kant is that his view prohibits all deception.
  • "Not Out of Lust But in Accordance With Truth: Theological and Philosophical Reflections on Sexuality and Reality."  Forthcoming in Logos.  An account of Christian sexual ethics centered on the notion of truth and reality.
  • "Christian Sexual Ethics and Teleological Organicity."  The Thomist 64 (2000) 71-100.  An account of Christian sexual ethics, particularly focusing on the immorality of contraception, centered on an analysis of the unitive dimension of sexuality and an argument that the unitive dimension is dependent on the procreative.
  • "Lying and speaking your interlocutor's language."  [Link might work only if your institution subscribes to The Thomist.] The Thomist 63 (1999) 439-453.  If one ought not lie even to the Gestapo officer at the door when one is hiding Jews, what should one do?
  • "I was once a fetus: an identity-based argument against abortion."  Work in progress.  To kill me earlier in my life inflicts a greater harm on me by depriving me of more.  I was once a fetus.  Therefore, to have killed me then would have deprived me of more than to have killed me now.  Since it is the harm to me that makes it wrong to kill me now, it would have been wrong to kill me when I was a fetus.  I also give a Rawlsian argument against abortion based the claim that I was once a fetus.  Most of the paper is a defense of the claim that I was once a fetus.
  • "I was once a fetus: that is why abortion is wrong."  Work in progress.  A shorter variant of the above argument.
  • "Maternal love and abortion."  Work in progress.  Some people are opposed to abortion in general because they loved their children when these were fetuses.  While this may be a psychological explanation of why these people believe thus, and perhaps an argument for these people not to abort the children they love, it does not at first sight seem to be an argument for the prima facie wrongness of abortion in general, and especially not an argument that other people have any reason to pay attention to.  I will argue that on the contrary the phenomenon of mothers loving their unborn children gives one a significant reason to think abortion to be prima facie wrong in general.

Mathematical papers