Article Text

Download PDFPDF
The inference from a single case: moral versus scientific inferences in implementing new biotechnologies
  1. B Hofmann
  1. Bjørn Hofmann, Section for Medical Ethics, Faculty of Medicine, University of Oslo, PO Box 1130, Blindern, N-0318 Oslo, Norway; b.m.hofmann{at}


Are there similarities between scientific and moral inference? This is the key question in this article. It takes as its point of departure an instance of one person’s story in the media changing both Norwegian public opinion and a brand-new Norwegian law prohibiting the use of saviour siblings. The case appears to falsify existing norms and to establish new ones. The analysis of this case reveals similarities in the modes of inference in science and morals, inasmuch as (a) a single case functions as a counter-example to an existing rule; (b) there is a common presupposition of stability, similarity and order, which makes it possible to reason from a few cases to a general rule; and (c) this makes it possible to hold things together and retain order. In science, these modes of inference are referred to as falsification, induction and consistency. In morals, they have a variety of other names. Hence, even without abandoning the fact–value divide, there appear to be similarities between inference in science and inference in morals, which may encourage communication across the boundaries between “the two cultures” and which are relevant to medical humanities.

  • inference
  • falsification
  • science
  • morals
  • induction
  • consistency

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.


  • Competing interests: None declared.

  • This article is based on a presentation, Fallacies in moral inference: how we implement new biotechnology, at the XXth European Conference on Philosophy of Medicine and Health Care, 23–6 Aug 2006.

  • i It is interesting that the initial skepticism and opposition with respect to new and controversial technologies, such as in vitro fertilisation (during the 1980s), cloning (during the 1990s) and PGD+HLA typing (during the 2000s), vanished as soon as one case showed up (for example, when people were confronted by a suffering face in the media). A more recent example is face transplants, where substantial opposition was swept away by the sight of a faceless person. Correspondingly, as cloning potentiality can be used for therapeutic purposes for visible, existing people, people’s attitudes will change.

  • ii Hence, I do not argue that moral theories are falsified by single cases. The relationship between moral ways of inference, moral norms and moral theories is complicated and is beyond the scope of this article.

  • iii This is not to say that moral reasoning can be reduced to scientific rationality. On the contrary, I argue that there are similarities in moral and scientific reasoning, which are of more general interest. However, the origin of this reasoning is beyond the scope of this article.

  • iv This exception was not explicitly discussed in the public debate, but seemed to be added at the end of the work.

  • v Monthly blood transfusions in combination with peritoneal infusion of deferoxamine five or six nights per week.

  • vi Since this article, also, uses a single case to make a point about moral reasoning and its potential relationship with scientific reasoning, the author is as subject to these inference patterns as anybody else is (hypothetically) expected to be.

  • vii I owe this point to Associate Professor Bjørn Myskja.

  • viii Correspondingly, the USA had the case of Molly (Fanconi anaemia); Denmark, that of Patrik (Fanconi anaemia); the UK, those of the Hashmis (β-thalassaemia) and the Whitakers (Diamond–Blackfan anaemia); and Switzerland, that of Noah. Hence, Mehmet’s is by no means exceptional, and many of the arguments that appeared in these cases9 were also prominent in Mehmet’s.

  • ix Note that ”moral falsification” can mean many things: (1) observation of an occurrence of immorality where the theory would predict an observation of morality, or vice versa; (2) presupposition of a metaphysical claim that has been falsified by experience; or (3) observing the general tendency of an instance of alleged immorality to go unpunished, or of an instance of morality to be punished.

  • x In Norway, PGD is allowed only if it is performed with regard to the potential child itself—that is, to avoid serious hereditary disease. Seven other criteria, very much inspired by the UK’s Human Fertilisation and Embryology Authority, regulate the conditions under which HLA typing is allowed—for example, that the child to be saved has a serious hereditary disease, that the donation will not harm the saviour sibling and that it will improve the health of the sibling who has the disease. Hence, PGD+HLA typing is still rather strictly regulated.

  • xi Actually, it was based on only one case, that of Mehmet, but it might be argued that it was supported by other, similar cases known from the international literature.

  • xii For discussions of the role of analogies in science, see, for example, B Hesse12 and MB Hesse.13

  • xiii A supposed old Arab saying is that you should not allow a camel to put his nose under the edge of your tent, for soon you will have a camel in your tent.

  • xiv One could argue that certain cases challenge the existing system of norms so fundamentally that they overthrow the existing system and form the basis of a new system. One could further argue that such cases parallel what Thomas Kuhn described as anomalies causing “scientific revolutions”.16 However, a discussion of this would be beyond the scope of this article. Suffice it here to point out that single cases may change the both moral and epistemic norms.

  • xv For example, it makes the slippery-slope argument an argument not of principle, but of pragmatism. It is not because of consistency that we will be led to accept B if we accept A, but because of empirical facts about the development of history.

  • xvi According to Quine, the falsifiability of an isolated empirical hypothesis is unavoidably inconclusive, because scientific statements cannot be confirmed or infirmed in isolation, but have to be assessed as a corporate body.

  • xvii White’s point is exactly that the same structure of falsification is at work both in what we traditionally call science and in ethics. Furthermore, we can reason from a false conclusion to one or more false premises (in a logically sound argument) even if the conclusion is normative and the premise is descriptive. However, his premise is that we cannot falsify in either science or morals on the basis of single cases. Like Quine, White argues that such falsifications are of bodies of beliefs only. Hence, Mehmet’s case could be used as a counter-argument (if not a falsification) of White’s account.

  • xviii The naturalistic fallacy is (imprecisely) claimed to be to reason from is to ought—for example, to deduce the moral status of embryos from steps in their biological development, or to avoid the moral challenges associated with prenatal diagnosis through improvement of diagnostic technology. Correspondingly (imprecisely), we could argue that “the humanistic fallacy” is to reason from ought to is: our concepts of how the world is are based on structures of how we believe it ought to be—for example, what photons, DNA and arthritis are depends (heavily if not primarily) on social activity and social norms. More precisely, G E Moore coined the term “naturalistic fallacy” for believing that a naturalistically specifiable property, such as being pleasurable, could be the same as a moral property, such as being good.