Since April 1st, 2023 I am professor of philosophical ethics at the Ethics Institute / Department of Philosophy and Religious Studies, Utrecht University. My main interest is in practical ethics, notably public health ethics, and in the relationships between moral philosophy, normative theory and practical ethical decision making. In the past years I have been working - obviously given my focus on public health - on ethical issues in relation to the COVID-19 pandemic. My major research theme however was vaccination ethics more in general. Together with Roland Pierik I wrote a monograph Inducing Immunity? The Justification of Collective Immunization in Times of Vaccine Hesitancy. The book was published in 2024 by MIT Press, in the Basic Bioethics book series, open access! 

A general theme in recent and presumably also upcoming years is to gain a better understanding of the normative character of the value of (health) solidarity, and its links with sustainability and justice. This theoretical issue is relevant to policy questions in relation to vaccination, infectious disease control, local and global health inequalities, and access to health care.

Currently (2026), I'm working on exploring injustices in relation to overweight and obesity, the role of ethics in scientific policy advice during a pandemic, and the impact of cancer screening on socioeconomic health inequalities. I'm also involved in ESDiT (Ethics of Socially Disruptive Technologies), a 10-years research program that is carried out at the Technical Universities of Twente, Delft Eindhoven and Wageningen, as well as Utrecht University. In this program my focus is on concepts of health, solidarity and justice, and how these are disrupted due to technologies such as immunization, weight-loss medicines, and digital technologies.  

My job as professor of philosophical ethics is not my first at Utrecht University, I studied at this university, and started my career at the Utrecht University Centre for Bioethics and Health Law, which later evolved in the Ethics Institute. For 5 years I worked as clinical ethicist at the Radboud University Medical Centre in Nijmegen; at the same time I wrote my dissertation Preventive Medicine Between Obligation and Aspiration. Given that there was only limited synergy between my work as clinical ethicist and my research in ethics of prevention, I returned to the Utrecht Centre for Bioethics, combining this with a postdoc position at the Department of Philosophy, University of Amsterdam. From 2002 to 2013  I had a fulltime position at Utrecht University, first as assistant professor, then as associate professor. In those years I initiated, together with Angus Dawson the International Association of Bioethics Network on Public Health Ethics. We also started the journal Public Health Ethics, published by OUP. In Utrecht,  Frans Brom and I started the MA program in Applied Ethics, which soon was granted Erasmus Mundus status, in a collaboration with Linkoping Trondheim, and Stellenbosch.

From 2013 to 2023 I was professor of philosophy at Wageningen University, leading the Philosophy group. This is a vibrant group of philosophers working on animal and environmental ethics, philosophy of technology and public health. In my last year I also lead the 4TU Centre for Ethics and Technology, of which Wageningen is one of the 4 partners.

Throughout my career I have taught ethics for a variety of student audiences: philosophy, medicine, dentistry, pharmacy, food sciences; but also professionals (nursing, medicine, public health, occupational health), also in guest positions at the universities of Keele (UK) and Stellenbosch (S-A) and the London School of Hygiene and Tropical Medicine.

My view on practical philosophy is to build bridges between theoretical analysis and practical moral problems in professional areas or public policy. This has resulted in in-depth analyses of problems in public health, such as: how far should professionals go in promoting health of citizens; what responsibilities do citizens have to take precautions against infection; and how should governments allocate scarce medical resources during an influenza pandemic. These are questions about health that go far beyond a medical-professional perspective; they concern responsibilities of all societal actors to contribute to health and quality of life.

My philosophical approach to practical societal issues is also the key in various consultative roles, for example for the World Health Organization. Since 2005, I have been member of the Health Council of the Netherlands and contributed to more than 25 advisory reports for the Minister of Health, including reports on collective vaccination, screening, preconception counseling, special policies for high-risk groups, and expert reports on Q-Fever and Mexican Flu. From 2016 to 2025 I was member of the Adviescommissie Pakket of Zorginstituut Nederland, a committee that advises on the content of the basic health insurance package.

I have been member of several research ethics committees, notably in the area of food research: TNO, Unilever Vlaardingen, and Wageningen University.

Key papers and books:

Inducing Immunity? Justifying Immunization Policies in Times of Vaccine Hesitancy. MITpress, 2024. (with Roland Pierik)

The (un)fairness of vaccination free riding. Public Health Ethics 2022;15(3): 233–239. 

Facing Difficult but Unavoidable Choices: Donor Blood Safety and Deferral of Men Who Have Sex with Men. Bioethics 2022;36(8): 840-848 (co-authored with Roland Pierik; Thijs van de Laar and Hans Zaaijer).

Sharing Responsibility: Responsibility for Health Is Not a Zero-Sum Game. Public Health Ethics 2019;12(2): 99–102. (co-authored with Angus Dawson)

Maternal Immunization: Ethical Issues. The Lancet Infectious Diseases 2016;16 (12): e310–e314. (co-authored with Philipp Lambach, Justin R Ortiz, and Andreas Reis, World Health Organization)

How (not) to argue for the rule of rescue. Claims of Individuals vs Group Solidarity. In: I. Glenn Cohen, Norman Daniels, and Nir Eyal (eds.) Identified versus Statistical Victims. An Interdisciplinary Perspective. New York: Oxford University Press, 2015: pp. 137-149.

Moral Principles for Allocating Scarce Medical Resources in an Influenza Pandemic. Journal of Bioethical Inquiry 2009;6(2):159-169

Ethics, prevention, and public health, edited AJ Dawson and MF Verweij. Oxford University Press, 2007.

Preventive Medicine Between Obligation and Aspiration (monograph) Kluwer/Springer, 2001.