●  Abortion and the Moral Significance of Merely Possible Persons:  Finding Middle Ground in Hard Cases, in Philosophy and Medicine, ed. H. Tristram Engelhardt (Springer 2010)

Abstract.  This book has two main goals.  The first is to give an account, called Variabilism, of the moral significance of merely possible persons—persons who, relative to a particular circumstance, or possible future or world, could but in fact never do exist.  The second is to use Variabilism to illuminate abortion.  

According to Variabilism, merely possible persons—just like anyone else—matter morally but matter variably.  Where we understand that a person incurs a loss whenever agents could have created more wellbeing for that person and instead create less, Variabilism asserts that the moral significance of any loss is a function of where that loss is incurred in relation to the person who incurs it.  That is:  a loss incurred at a world where the person who incurs that loss does or will exist has full more significance, according to Variabilism, while a loss incurred by that same person at a world where that person never exists at all has no moral significance whatsoever

Some other views deem all merely possible persons and all of their losses to matter morally.  Still other views deem no merely possible persons and none of their losses to matter morally.  Variabilism, instead, takes a middle ground between these two extreme positions.  It thus opens the door to a certain middle ground on procreative choice in general and abortion in particular.  Thus, given that, for persons, thinking and coming into existence come together, Variabilism supports the argument that the early abortion is ordinarily permissible when it is what the woman wants.  That is so, since the loss incurred when, as an effect of the early abortion, a given person is never brought into existence to begin with has no moral significance at all.  In contrast, the late abortion is ordinarily subject to a different analysis.  For the loss incurred in that case has full moral significance, according to Variabilism, since it is incurred at a world where the person who incurs it already exists.

Abstract at Springer

●  Harming Future Persons:  Ethics, Genetics and the Nonidentity Problem, eds. M. Roberts and D. Wasserman, in International Library of Ethics, Law, and the New Medicine (Springer 2009) 

Includes papers by Heyd (explaining and defending the person-affecting intuition and relating nonidentity problem to issues of biographical identity), Persson and McMahan (on the Asymmetry), Holtug (proposing a solution to the nonidentity problem with elements sufficiently person-affecting to sidestep the repugnant conclusion), Wolf (on identity), Mulgan (on a rule consequentialist solution to the nonidentity problem), Harman and Steinbock (on when it is wrong to bring the harmed child into existence), Hanser (on standing in an appropriate relation to the harmed child as a condition on causing harm), Roberts (on analogies between one type of nonidentity problem and the two-envelope problem, and approaches to each that focus on the information available to the agent at the critical time), Lillehammer, Herissone-Kelly and Wasserman (on considerations relating to attitude, intention and parental role as helping to the nonidentity problem), Arrhenius (on structural and coherence issues relating to the person-affecting approach generally) and Peters and Shiffrin (on the nonidentity problem, law and public policy).

Abstract at Springer

●  Child Versus Childmaker:  Future Persons and Present Duties in Ethics and the Law (Rowman & Littlefield 1998)

Chap. 1.  Introduction

Chap. 2:  Is the Person-Affecting Intuition Inconsistent? -- John Broome has argued that the person-affecting intuition is inconsistent.  I develop an alternative statement of the person-affecting intuition -- a form of person-affecting consequentialism -- that avoids that inconsistency objection.  Based on the four-place relation "p has at least as much wellbeing in w1 as q does in w2," the principles I suggest focus on maximizing wellbeing not for the aggregate but rather for individual.  Thus for each existing or future person, the proposal is that, with exceptions to address trade-offs, agents ought to make choices that maximize that person's wellbeing.

Chap. 3:  The Nonidentity Problem -- Derek Parfit, Gregory Kavka and others put forth the "nonidentity problem" as a challenge to person-affecting principles generally.  I consider how three variations on the nonidentity problem apply to the form of person-affecting consequentialism I describe in Chap. 2.  My conclusion is that two variations of the nonidentity problem are inconsistent with the basic tenets of person-affecting consequentialism and can be safely set aside, and that the third variation leads to results that are not implausible.

Chap. 4:  Wrongful Life -- I argue that in some instances the choice to bring a new person into existence can harm a person -- create, that is, less wellbeing for a person when agents could have created more -- and that that harm can ground a finding of wrongdoing.  I thus argue that it is sometimes better for a person never to come into existence at all than to come into an existence that is highly flawed.

Chap. 5:  Human Cloning -- John Robertson has argued that "harm to offspring" objections fail in the case of the new reproductive technologies.  His argument derives from the ideas that (i) in the absence of the new technologies the offspring would not exist at all and (ii) the offspring lives are worth living.  Robertson's conclusion is that offspring in general are not harmed, or wronged, by application of those new technologies.  I argue that when cloning is used to produce -- say -- five, or fifty, or a thousand genetically identical people, we can see just how agents could have gone about making things better for any one of those people.  They could have brought one embryo, but not all those others, to fruition.  We, accordingly, find that we have a clear basis after all for declaring the cloned individual to have been harmed.

  Modal Ethics (in progress)   

Applications of world theory to issues in normative and population ethics, including (1) obligations in respect of future persons (including the nonidentity problem and the aggregative response, as well as obligations to procreate), (2) the question of “who matters morally,” (3) determining when one act (including any omission) makes things better for a person than another act does, (4) relating the two-place overall betterness relation to the four-place betterness-for relation (including Pareto issues) and (5) comparability issues (can a person be better (worse) off at a world where that person never exists than at a world where that person does or will exist?).

●  Doing the Best We Can:  Dialogue Concerning Future Persons, Harm and the  Nonidentity Problem (in progress)

This dialogue is intended to facilitate the teaching of the nonidentity problem, the person-affecting, or person-based, approach in ethics and issues having to do with the obligations we have in respect of future persons.  Comments very welcome!


  In Progress:

●  "The Moral Effluvia of Existence:  Can Existence Make Things Better for a Person?  And So What If It Can?"

●  Roberts, "Does the Moral Significance of Merely Possible People Imply that Early Abortion Is Wrong?"

●  Roberts, "The Two Envelope Problem and the Man Who Knew Too Much"

Published or Accepted for Publication:

   ● "Can Procreation Impose Morally Significant Harms or Benefits on the Child?  And So What If It Can?"  Newsletter on Philosophy and Medicine (American Philosophical Association forthcoming 2014)

●  "Population Axiology," Oxford Handbook of Value Theory, eds. Iwao Hirose and Jonas Olson, Oxford University Press (forthcoming 2014)

●  "Temkin's Essentially Comparative View, Wrongful Life and the Mere Addition Paradox" (symposium) Analysis (forthcoming 2014)

●  "The Nonidentity Problem," Stanford Encyclopedia of Philosophy (2013)

●  "The Nonidentity Problem," International Encyclopedia of Ethics, ed. Hugh LaFollette (Wiley-Blackwell 2013)

●  "Population Ethics," International Encyclopedia of Ethics, ed. Hugh LaFollette (Wiley-Blackwell 2013)

●  "Moral and Legal Constraints on Human Reproductive Cloning," in Families:  Beyond the Nuclear Ideal:  For Better or Worse?  eds. D. Cutas and S. Chan (Bloomsbury 2012)

●  "Does the Nonidentity Problem Imply a Double Standard for Physicians and Patients?" Response to Hope and McMillan, American Journal of Bioethics (2012)

●  "An Asymmetry in the Ethics of Procreation,"  Philosophy Compass 6.11 (2011) 765-776

●  "Harming in the Multiple Agent Context," Ethical Perspectives 18 (2011) 313-340

         "Harming in the Multiple Agent Context" (draft)

●  "The Asymmetry:  A Solution," Theoria 77 (2011) 333-367

●  "Procreation, Abortion and Harm:  Comment" --  2.9 Newsletter on Philosophy and Medicine 20-23 (American Philosophical Association 2010)

●  "The Nonidentity Problem," Stanford Encyclopedia of Philosophy (July 2009)


●  "The Nonidentity Problem and the Two Envelope Problem:  When Is One Act Better for a Person than Another?"  In Harming Future Persons, eds. Roberts and Wasserman, Springer (2009), pp. 201-228.

The nonidentity problem and the two envelope problem have in common an ongoing resistance to intuitive analysis.  They also share certain structural features.  I argue that the two problems proceed under the same error, imagining subjects to draw haphazardly from a potpourri of actual and expected values to generate results about betterness and harm rather than, as we naturally do and always should, draw in a more discriminating way from a more orderly array.  When we play by the same set of rules in calculating the values that we then compare, we, in particular, become able to discern (1) harm in just the cases in respect of which one important variation on the nonidentity problem has long been thought to show “no harm done” and (2) no harm done in the two envelope problem, which purports to show “harm done” when the subject refuses endlessly to switch from one envelope to another and back again.

 "Harming Future Persons:  Introduction," with David Wasserman.  In Harming Future Persons, eds. Roberts and Wasserman, Springer (2009), pp. viii-xxxviii.

 "What Is the Wrong of Wrongful Disability?  From Chance to Choice to Harm to Persons," 28(1) Law and Philosophy 1-57 (2009)

          Draft of "What Is the Wrong of Wrongful Disability?"

          Link to final text at Law and Philosophy       

The issue of wrongful disability arises when parents face the choice whether to produce a child whose life will be unavoidably flawed by a serious disease or disorder (Down syndrome, for example, or Huntington’s disease) yet clearly worth living.  The authors of From Chance to Choice claim, with certain restrictions, that the choice to produce such a child is morally wrong.  They then argue that an intuitive moral approach—a “person-affecting” approach that pins wrongdoing to the harming of some existing or future person—cannot account for that wrong since the choice to produce such a child cannot, under the logic of the nonidentity problem, harm that child.  The authors propose that we supplement the person-affecting approach with an “impersonal” principle that takes the form of their well-known principle N.  In this paper, I argue that the authors are mistaken to suppose that a plausibly articulated person-affecting approach cannot account for the wrong of wrongful disability.  We can retain an intuitive, comparative, “worse for” account of harm and still identify serious harms imposed by the choice of wrongful disability.  In particular, I argue that harm, both to the impaired child and to others, comes not in the form of that procreative choice’s procreative effect but rather in the form of its many distributive effects.  I argue, moreover, that that harm result can support the claim that the parents' choice is morally wrong as well as the impaired child's legal claim (for "wrongful life") against the health care provider whose negligent failure to diagnose or inform parents of an increased risk of a genetic or congenital impairment results in the birth of the impaired child.   

●  "The Nonidentity Fallacy:  Harm, Probability and Another Look at Parfit's Depletion Example," 19 Utilitas 267-311 (2007)

          Draft of "The Nonidentity Fallacy"

          Link to final text at Utilitas

The nonidentity problem is a collection of problems having distinct logical features. For that reason, they can be typed. This paper focuses on just one type of nonidentity problem, the ‘can’t-expect-better’ problem, which includes Derek Parfit’s depletion example and many others. The can’t-expect-better problem uses an assessment about the low probability of any particular person’s coming into existence to reason that an earlier wrong act does not harm that person. This paper argues that that line of reasoning is unusually treacherous in that it makes not just one hard-to-detect error in what is done with the relevant probability assessments but rather alternates between two. We sort out one mistake only to fall, against all odds (as it were), into a second. By avoiding both errors, we become able to discern harm in cases in which the can’t-expect-better problem argues there is none. We will then be in a position to set aside the can’t-expect-better problem as an objection against the person-based intuition that acts that are ‘bad’ must be ‘bad for’ at least some existing or future person.

●  Review, Tim Mulgan Future People:  A Moderate Consequentialist Account, 116 Mind 770-775 (2007)

●  "Supernumerary Pregnancy, Collective Harm and Two Forms of the Nonidentity Problem," 34 Journal of Law, Medicine & Ethics 277-292 (2007)

          Draft of "Supernumerary Pregnancy"

          Link to final text at Jo. Law, Medicine and Ethics

An interesting question, in both the moral and the legal context, is whether the babies born of an infertility treatment-induced supernumerary (or multi-fetal) pregnancy (or “ITISP”) are properly considered to have been harmed.  One might wonder how such a question could even arise in the face of data that clearly demonstrate that ITISP leaves an unduly large number of babies blind, deaf and palsied and facing life-long disabilities.  In fact, however, a number of arguments, based on the problem of collective harm and two forms of the so-called “nonidentity problem,” challenge the claim of harm in the ITISP context.  The purpose of the present paper is to establish, as against these arguments, that harm has been imposed on the ITISP-damaged offspring.

●  "Person-Based Consequentialism and the Procreation Obligation," The Repugnant Conclusion: Essays in Population Ethics (eds. J. Ryberg and T. Tännsjö) 99-128 (Springer, 2005)

          Link to TOC for the collection and to my paper

This article explores a person-based account of the repugnant conclusion, investigating, along the way, the "extinction problem" as a leading challenge to such an account.  The argument is made that a careful consideration of what we understand our own obligations to be in contemporary life -- including our obligations with respect to already-existing people -- casts doubt on the idea that, in general, agents have an obligation to bring new people into existence just in case doing so will contribute to total, aggregate, utility or wellbeing. 

●  "Supernumerary Pregnancy and the Limits of the Constitutional Privacy Guaranty," Jo. of Philosophical Research 105-117(2005)

The claim of this article is that the privacy guaranty of the Fourteenth Amendment does not protect the choice to commence or continue a supernumerary pregnancy when the consequence of doing so presents risks of harm to prospective offspring in the form of physical, intellectual or emotional deficiencies.  This is so, it is argued, notwithstanding the fact that the reproductive choice (for example, the use of strong fertility drugs in the absence of procedures designed to avoid multiple pregnancy) is part of the causal chain that eventuates in the existence of those offspring, who (probably) would never have otherwise existed at all. 

●  "Is the Person-Affecting Intuition Paradoxical?" 55 Theory and Decision 1-44 (2003)

Link to final text at Theory and Decision

This article critically examines some of the inconsistency objections that have been raised by John Broome and Larry Temkin against the so-called "person-affecting" restriction in normative ethics, including "additional people" problems (especially the mere addition paradox and issues relating to "Pareto-Plus") and a version of the nonidentity problem from Kavka and Parfit.  Paradoxes can be avoided, it is argued, by situating the person-affecting intuition within a certain form of maximizing consequentialism (in competition with "total" and "average" forms of maximizing consequentialism). 

●  "Can It Ever Have Been Better Never to Have Existed At All?  Person-Based Consequentialism and a New Repugnant Conclusion," 20 Jo. of Applied Philosophy 159-185 (2003)

          Draft of "Can It Ever Have Been Better"

This article critically considers a handful of arguments to the conclusion that statements purporting to assert that never having existed at all can be better, in the case of some individuals, than existence are always incoherent or at least untrue.  The article concludes that such arguments fail and that it is both coherent and plausibly true that it would have been better, in the case of certain persons, that they never have existed at all. 

●  "A New Way of Doing the Best That We Can:  Person-Based Consequentialism and the Equality Problem," 112 Ethics 315-350 (2002)

          Corrected "A New Way of Doing the Best That We Can" 

          Link to final text at Ethics

This paper argues that a person-affecting, or "person-based," form of consequentialism includes the best features of traditional, aggregative forms of maximizing consequentialism yet is not vulnerable to many of the most telling objections such forms of consequentialism.  Among other things, person-based consequentialism leaves a clearly defined role for considerations of equality.  This paper also suggests that the "leximin" principle captures much of what we think is right about equality without taking us too far in the direction of "equalism."

●  "Cloning and Harming:  Children, Future Persons and the 'Best Interest' Test," 13 Notre Dame Jo. of Law, Ethics & Public Policy 37-61 (1999)

We can predict that, should reproductive cloning ever become an option, we adults will insist on the right of consent before we will allow our own genomes to be used for purposes of reproductive cloning.  Whether conceived of in legal or moral terms, what we aim to protect in insisting on a right of consent is an interest in "privacy."  This article argues that the same interest should be respected in the case of children and future persons.  Just as we would not (and in many states legally should not) use a child -- who is in no position to consent -- as a kidney donor unless we are sure that acting as such a donor is in the child's own best interest, I argue that neither children nor future persons should be used as clone sources or intentionally brought into existence as clones -- as one of two or more genetically identical individuals -- unless there is a clear showing that such a violation of their interest in privacy serves their own best interest.

●  "Human Cloning:  A Case of No Harm Done?" 21 Jo. of Med. and Phil. 537-54 (1996)

Link to final text at Jo. of Med. and Phil.

The focus of this article is the nonidentity problem, developed by Parfit, Kavka and others, and its application to reproductive cloning technologies.  John Robertson has put forward a version of the nonidentity problem as an argument that reproductive cloning will not cause harm to the offspring that it will be used to produce.  Richard McCormack has argued that the acceptance of human reproductive cloning would undermine the dignity of the human embryo and would constitute a breach of the respect that he thinks we owe to the embryo as human.  The terms of their debate suggests that one must either support human reproductive cloning or reject abortion as a morally permissible option.  I argue, however, that we can identify respects in which reproductive cloning causes specific sorts of harm to offspring and hence that we have grounds to reject human reproductive cloning that have no adverse implication for our full and robust support for the right of abortion.

●  "Parent and Child in Conflict: Between Liberty and Responsibility," 10 Notre Dame Jo. of Law, Ethics and Public Policy 485-542 (1996)

The focus of this article is the case of "Baby Richard," who, after a failed adoption, was returned at the age of four to a biological father whom the child had never seen before.  The main argument of the article is that, just as adults have parental rights that we think warrant protection under the Fourteenth Amendment's due process guaranty, so should children be understood to have "affiliational" rights that likewise merit constitutional protection.  Such rights would counterbalance in extreme circumstances the parent's right of custody and control with respect to his or her own biological offspring.

●  "Present Duties and Future Persons: When Are Existence-Inducing Acts Wrong?" 14 Law and Philosophy 297-327 (1995)

This article takes a close look at the nonidentity problem in its many forms.  Thus, counterfactual, probabilistic and more broadly modal forms of the argument are considered and, in some cases, rejected as flawed.  The analysis has been revised and clarified in Chapter 3 of Child Versus Childmaker ("The Nonidentity Problem").

●  “Sexual Harassment, the Acquiescent Plaintiff and the ‘Unwelcomeness’ Requirement,” in D. Bushnell, ed., Nagging Questions (Rowman & Littlefield, 1995) 105-121

This article considers a certain requirement that the Supreme Court has imposed in connection with claims brought for sexual harassment under Title VII of the Civil Rights Act, as amended.  According to the Supreme Court, the plaintiff must establish that the defendant’s conduct, in addition to creating unreasonable burdens on the plaintiff that discriminate against the plaintiff on the basis of her sex, is “unwelcome” to her.  Meritor Savings.   This article argues that the unwelcomeness requirement is unjustified.  It is very difficult for the plaintiff to establish her subjective “state of mind” months or years after the questionable conduct occurred.  Moreover, it is a requirement that serves no clear policy or legislative purpose, in view of the other showings of fact that the plaintiff is independently required to make under Title VII. 

●  "A Way of Looking at the Dalla Corte Case," 22 Jo. of Law, Medicine and Ethics 339-42 (1994)

I argue that, when the postmenopausal woman's own ongoing partner is the sperm source, it is difficult to conclude that postmenopausal pregnancy is somehow immoral or should be made illegal.  This argument leaves the question of moral status open in the case were both egg and sperm are donated.  In both cases, the main concern would be the consequences of the technology for the child.  In the former case, it is difficult to see any other reasonable alternative by which the particular child could both exist and not suffer the risk of having a beloved parent die when the child is still young.  In the latter case, it is easy to pinpoint an alternative course of action that would allow the particular child both to exist and avoid the risk.  The moral analysis thus seems to be different in the one case as compared to the other.

●  "Good Intentions and a Great Divide: Having Babies by Intending Them," 12 Law and  Philosophy 287-317 (1993)

The focus of this article is commercial surrogacy and Richard Posner's argument that, from the child's point of view, no objection to commercial surrogacy can be sensibly made in view of the fact that the child owes his or her very existence to the practice of surrogacy.  I argue that this defense of surrogacy is flawed in view of the fact that by the time the question of the contract's enforceability is properly raised the child exists; declaring the contract unenforceable will not in any way change that fact.  At the same time, declaring the contract unenforceable represents a step forward from the child's point of view since it means that the child's placement will be determined, not by the terms of the commercial contract, but rather in accordance with the child's own "best interest."

●  "Distinguishing Wrongful From ‘Rightful' Life," 6 Jo. of Contemporary Health Law and Policy 59-80 (1990)

This paper argues that the tort of "wrongful life" should be recognized.  The particular focus is on arguments that conclude that claims of wrongful life are somehow self-contradictory or incoherent.  I argue that they are neither.


●  "The Moral Effluvia of Existence:  Can Existence Make Things Better for a Person and So What If It Does?"  Society for Applied Ethics, Oxford University (June 2014)

●  "Rethinking 'Mere Addition':  Can Adding Happy People Make Things Worse?" American Philosophical Association Pacific Division Meetings (San Diego 2014)

●  "Can Procreation Impose Morally Significant Harms or Benefits on the Child?" American Philosophical Association Eastern Division Meetings (Baltimore 2014)

●  Comment on Tim Campbell, "Infinite Utility and Cain's Paradox," Rocky Mountain Ethics Congress/RoME V (2012)

●  Comment on Howard Nye, "Responsibility for Vulnerability and the Non-Identity Problem," American Philosophical Association Pacific Division Meetings (San Francisco 2013)  

●  "Wrongful Life and Wrongful Birth," seminar presentation, New York University (Nov. 2011)

●  "Variabilism and the Asymmetry," University of Tennessee, Knoxville (Oct. 2011)

●  "The Person-Affecting Approach in Ethics," super-seminar, University of Tennessee at Knoxville (Oct. 2011)

●  "Variabilism and the Asymmetry," Rocky Mountain Ethics Congress (RoME IV) (Aug. 2011)

●  "Procreative Reasons, Procreative Obligation and Procreative Liberty," Dubrovnik Conference On Moral Philosophy and Value Theory (June 2011)

●  "The Two Envelope Problem:  The Man Who Knew Too Much," faculty colloquium, University of Delaware (Apr. 2011) 

●  "The Nonidentity Problem," student seminar, University of Delaware (Apr. 2011)

●  "A Variabilist Solution to the Asymmetry," Workshop on Population Ethics, McGill University, Montreal (Mar. 2011)

●  "A Variabilist Solution to the Asymmetry," Philamore Ethics Reading Group (Mar. 2011)

●  "Abortion and the Moral Significance of Merely Possible Persons," Stockholm University (Dec. 2010) 

●  "Abortion and the Moral Significance of Merely Possible Persons," University of Copenhagen (Nov. 2010)

●  "The Asymmetry and Genetic Enhancement," Workshop on Justice and Reproduction, The Nordic Network for Politics and Ethics (University of Gothenburg, Nov. 2010)

●  "Causing Harm in the Multiple Agent Context," Université catholique de Louvain, International Bernheim Workshop (Oct. 2010)

●  Comment on Saul Smilansky's "Should We Be Sorry We Exist?" Rocky Mountain Ethics Congress (RoME III) (Aug. 2010)

●  "Does the Moral Status of Merely Possible Persons Imply that Early Abortion Is Wrong," poster presentation, Rocky Mountain Ethics Congress (RoME III) (Aug. 2010)

            Poster on Abortion and the Moral Status of Merely Possible People

●  "Does the Moral Status of Merely Possible Persons Imply that Early Abortion Is Wrong?" Society for Applied Philosophy Annual Conference (St. Anne's College, Oxford, July 2010)

●  Comment on John Broome, "Climate Change:  How Bad Is the Chance of Catastrophe?"  DeCamp Seminar (University Center for Human Values, Princeton, Mar. 2010)

●  "An Asymmetry in the Ethics of Procreation:  Can It Be Permissible Not to Bring the Happy Child into Existence Yet Obligatory to Leave the Miserable Child Out of Existence?," Conference on What Do We Owe to Future Persons, Cluster of Excellence/The Formation of Normative Orders, Goethe University (Frankfurt, Feb. 2010)

●  Comment on Dillard, Harman, Kamm and McMahan, "Procreation, Abortion and Harm," Committee on Philosophy and Law, American Philosophical Association Eastern Division Meetings (Dec. 2009)

●  "Does the Moral Status of Merely Possible Persons Imply that Early Abortion Is Wrong?" New Jersey Regional Philosophical Association (Montclair State University, Nov. 2009)

●  "Counting the Costs Before They're Hatched:  Climate Change, the Nonidentity Problem and the Moral Significance of Merely Possible Persons," Conference on the Ethics of Climate Change:  Intergenerational Justice and the Global Challenge, University of Delaware Department of Philosophy and the American Philosophical Association (Newark, Del., Oct. 2009)

         Link to full text

●  "Do Principles of Justice Extend to Merely Possible Persons?" Conference, Extensions of Justice, The Hebrew University of Jerusalem (Mount Scopus, June 2009)

          Link to full text

●  Comment on Holly Smith, "Error and Uncertainty in Moral Decision-Making," Felician Ethics Conference (Apr. 2009)

●  "Abortion and the Moral Significance of Merely Possible Persons," University of Delaware at Newark (Nov. 2008)

          Link to full text

●  Comment on Rivka Weinberg, "Existence:  Who Needs It?" University Center for Human Values, Princeton University (Nov. 2008)

●  "The Nonidentity Problem and the Two Envelope Problem," University of California at Riverside (Feb. 2008) 

●  “Climate Change and the Problem of Collective Harm,” comment on Andrew Light, Society for Applied Philosophy, Princeton Theological Institute (Oct. 2007)

●  Comment on Larry Temkin, “Equality and Health Care,” University Center for Human Values, Princeton University (Sept. 2006)

●  "When Do We Harm Persons by Causing Them to Exist?  Expected Value, Betterness and the Slave Child Case," University Center for Human Values Decamp Seminar (Princeton, Oct. 2006)

●  “Supernumerary Pregnancy and Harm to Persons,” Center for Bioethics, University of Pennsylvania (Hart Lecture, June 2006)

●  "Assisted Reproductive Technologies and Harm to Offspring," The American Society of Law, Medicine & Ethics 28th Annual Conference for Health Law Teachers (Newark, June 2004)

●  Comment on Noam J. Zohar, "Divine Representations and the Value of Embryos:  God's Image, God's Name and the Status of Human Non-Persons," Center for Judaic Studies and University Center for Human Values (Princeton, 2004)

●  Comment on David Wasserman, "Is Every Birth Wrongful?  Is Any Birth Required?"  University Center for Human Values (Princeton, 2004)

●  "The New Reproduction Technologies and the Limits and Structure of Constitutional Privacy," American Philosophical Association -- Pacific Division Meetings (San Francisco, Mar. 2003)

●  "The Structure of Constitutional Privacy:  The 'Right' To Be Left Alone As a Hierarchy of Critical Privacy Interests," American Society for Value Inquiry (Milwaukee, Apr. 2002)

●  Comment on Adrienne Asch, “Selling of Human Ova,” University Center for Human Values (Princeton, 2002)

●  "Person-Based Consequentialism and the Equality Problem," American Philosophical Association -- University of Delaware Ethics in the Twenty-First Century (Newark, Delaware, Nov. 2001)

●  "Am I As Good As You Are?  Two Forms of Consequentialism and Two Approaches to the Equality Problem," American Philosophical Association -- Pacific Division Meetings (Oakland, April 2001)

●  "Cloning and Harming," American Philosophical Association -- Pacific Division Meetings (Berkeley, Apr. 1999)

●  "Is the Person-Affecting Intuition Inconsistent?" American Philosophical Association -- Pacific Division Meetings (Berkeley, Apr. 1997)