It is common to hear that humans have ‘use’ or are ‘useful’. Working together and being employed in tasks of many kinds means that we regularly have our usefulness appraised. We often apply concepts of use in the workplace and apply them to specific human capabilities – ‘is she good that?’ ‘Do you think we could use David for this project?’ – and one might hypothesise that modern capitalist attitudes to human labour seek to maximise the possible uses of the human body for the maximisation of profit. But I am not terribly interested in this idea of ‘labour’ as an adequate expression of use, since a human’s usefulness cannot be limited to a period of time and, as Quentin Meillassoux has demonstrated, the human cannot be relied upon for measures of what time might be. I leave it to Marxist political philosophers to consider how our conception of human use is predicated on time, since what I am interested is a use that comes from simply living. That is, I am interested in research that finds humans useful not just for what they do but also for what they are biologically.
Human twins, I think, offer a good example of when a human is thought to be useful without having to do one thing or another. In fact, psychologists and geneticists are particularly drawn to twins not for what they do together, nor, especially, for what they do apart (though these are important), but for simply being born together and sharing a certain amount of genetic material, inter-uterine and post-natal environments. Their behaviour, when compared to non-twins or when offset against differences found between genetically ‘identical’ and genetically ‘non identical’ sets, can tell us the different roles being played by our genes and the environments we live in. So their use in these scientific practices is attached to the biological fact of twins and not, like bus drivers or nurses, to roles that they perform for others or themselves.
Both working and at rest, both awake and unconscious, whether existing in a system of capitalist exchange or through another means of subsistence, human twins are considered ‘useful’ in contemporary biological research simply by being what they are: two conceived and born together. With over 140 twin registries in the world carrying biometric data of hundreds of thousands of twin sets, twins are assisting and have assisted in some major breakthroughs in genetics in the last 20 years. Some estimate that as many as 1.5 million twins and their families are participating in twin studies worldwide. They participate in about 9% of all genome-wide association studies globally. In a recent article in the journal Twin Research and Human Genetics, authors Yoon-Mi Hur and Jeffrey M. Craig argue that the storage of twin data and the growth in new twin registries reflects the increasing importance of twins in contemporary genetics. The authors suggest that it is now “well recognized in the scientific community that twins are powerful and flexible tools to achieve understanding of the biological substrate of complex human diseases and behaviors (2013; 1, my emphasis)”. Part of their use is that they are living tools, they are not synthesised in a lab but occur separate to the interests of research itself. It is as if twins will be what they are, whether they are measured, weighed, have their blood and saliva sampled for DNA analysis, have their bone density scanned or complete pages upon pages of questionnaires that hope to capture their differences and similarities. This is why those who employ twins as research tools, despite ongoing criticisms, have been described by geneticists as a “naturally occurring experimental situation” (Spector 2012) that offers “unique insight” (Segal 2012) into our genetic make up and the way in which we are affected by our environment. Whether or not we agree with these claims, the agency of twins to be useful cannot be compared to the multiple ways in which the twin studies method can make them useful, not for what they do, simply for what they are.
Galton, Francis. ‘The History of Twins as a Criterion of the Relative Powers of Nature and Nurture,’ Journal of Anthopological Institute of Great Britain and Ireland 5, (1875): 391–406.
Hur, Yoon-Mi and Jeffrey M. Craig. ‘Twin Registries Worldwide: An Important Resource for Scientific Research.’ Twin Research and Human Genetics 16 (2013): 1-12. doi:10.1017/thg.2012.147.
Segal, Nancy L. Born Together–Reared Apart: The Landmark Minnesota Twin Study. Cambridge, MA: Harvard UP, 2012.
Spector, Tim. Identically Different: Why You Can Change Your Genes. W&N: London, 2012.
—. ‘The Use of Twins in Research’. BRC Biomedical Forum, Guy’s Hospital, 9th January 2013.