A unique ethical concern about synthetic biology is that it may result in the creation of entities which fall somewhere between living things and machines.
It is not difficult to see why some products of synthetic biology might fail to fit comfortably into our intuitive dichotomy between the living and the non-living. Consider, for example, the bacterial bio-factories that synthetic biologists hope to construct by adding suitable modules to a minimal bacterial chassis. These bio-factories might possess many of the characteristics that we ordinarily take to be definitive of life: for example, homeostatic physiological mechanisms, a nucleic acid genome and protein-based structure, and the ability to reproduce. But they would also possess many of the features characteristic of machines: for example, modular construction, based on rational design principles, and with specific applications in mind. Alternatively, consider the more remote but not entirely fantastic possibility of a synthetic bio-computer which performs many of the tasks currently performed by PCs, but which is based not on the silicone chip, but on neural networks composed of synthetic human nerve cells.
Entities such as these certainly test our intuitive dichotomy between the living and the non-living in ways that it has hitherto not been challenged. What is less clear, however, is that difficulties about how to classify synthetic entities present any ethical objection to producing them.
One concern could be that creating organisms with the features of both organisms and machines will change how we view existing kinds of life. Mildred Cho and collaborators worry that it will lead us to adopt a wrongheaded reductionist account of life, according to which life is nothing more than a set of biochemical components, or, more restrictively, a set of genes. This, in turn, will undermine ‘the special status of living things and the value that we ascribe to life’. The concern here appears to be that we will cease to regard the distinction between living things and machines as important. But—the argument would go—this distinction is important, for machines and living things differ significantly in their moral status. Machines, such as computers, have no intrinsic value (they are valuable only insofar they can be used to bring about valuable ends), no interests and no rights. Organisms, on the other hand, may possess all of these things. Thus, if the significance attached to the distinction between living things and machines were eroded, we might wrongly come to see living things as possessing less moral status than they actually have.
This argument seems to overblow the significance of life, however. There are many living things (bacteria, for example) to which we already ascribe no moral status. We feel quite justified in killing or exploiting bacteria whenever it suits us. We certainly do not think that in doing so we a breaching their rights, obstructing their interests, or denying their intrinsic value: bacteria possess none of these things. This is because moral status is conferred not by life, but by characteristics that some living things possess (sentience, consciousness, self-consciousness and rationality are among the most obvious candidates).
Perhaps the concern can be re-stated in a more plausible form. It could be argued that accepting reductionist accounts of life would lead us to underestimate the moral status of those living things that do possess moral status. However, it is unclear why this should necessarily be. Many people already accept reductionist accounts of life while still regarding at least some conscious beings as having special moral status.
The real concern in this area is not that we will come to underestimate the moral status of existing living things, but that we will misjudge the moral status of some of the new entities that synthetic biologists may produce. We are, after all, often uncertain or mistaken in our assignments of moral status. While we can be confident that persons have significant moral status, and machines do not, there is plenty of grey area in between where we are less certain. To see this, we need only to survey the literature on the moral status of non-human animals and human embryos. Moreover, it seems plausible that many synthetic entities would fall within this grey area. Perhaps we could be confident that a minimal bacterial chassis would possess no significant moral status. But we might be less confident about a bio-computer constructed from synthetic human-like nerve cells. Arguably, we should not create such a being until we have ascertained what moral status it would have, and thus, how we should treat it.
Synthetic biology may, then, highlight the need for more secure accounts of what determines moral status than we currently have. However, the ethical work necessary to develop such accounts is already underway. Ethical controversies about abortion, stem cell research, human-nonhuman chimeras, artificial intelligence and the treatment of animals have ensured that questions about moral status enjoy a high priority on the bioethics agenda. Discussion of the determinants of moral status has even made its way into recent debate on the ethics of cognitive enhancement. Those reflecting about the direction of synthetic biology will be able to piggyback off a rich and thriving literature on moral status. The need for specific attention to the moral status issues raised by synthetic biology is limited.