As a word, principlism may be clumsy and unpronounceable, but as an explanation of medical ethics, it is supreme. The four principles of autonomy, beneficence, non-maleficence, and justice have become an ethical mnemonic for medical students, a framework for solving all ethical conundrums.

Principlism has dominated bioethical discourse for the last half-century and often acts as a scaffolding for ethical reports on controversial issues. It was first articulated by Beauchamp and Childress in their landmark text, Principles of Biomedical Ethics, which was first published in 1979 and has gone through several editions.

Inevitably, the four principles have been used to analyse the rights and wrongs of the two most contentious issues of our time, abortion and euthanasia.

Is principlism up to the job? In a very interesting paper in the journal Medicine, Health Care and Philosophy, two Australian scholars, Brieann Rigby and Xavier Symons, argue that “Whilst principlism is a useful framework to address bioethical dilemmas, the principles alone are unable to resolve complex moral issues, including the ethics of abortion and euthanasia.”

The main weakness of the principlist approach is that its metaphysics is weak. It is not supported by a robust understanding of what a “person” is. Therefore, it cannot be deployed adequately in the abortion debate, which is fundamentally about personhood.

Beauchamp and Childress forge an argument in support of euthanasia as an expression of a patient’s autonomy. But this seems to glide over the “moral uncertainty” inherent in their theory.

Rigby and Symons point out that while the four principles help to clarify terms of the debate, they cannot solve it. Other principles which principlism ignores are needed, notably in the euthanasia debate:

Dignity, may be one such principle. Vulnerability may be another (and indeed some authors have proposed vulnerability as a fifth principle that ought to inform principlist bioethical reasoning). To limit one’s analysis of the euthanasia debate to an application of the principles, therefore, seems fated to deliver partial and inconclusive analyses.

The authors insist that this is not necessarily a criticism of the principles as such, simply a recognition of their limitations. They conclude: “it seems unrealistic to expect a theory to command both universal appeal and also provide definitive resolutions to divisive social debates.”