The scientific, ethical, and policy issues raised by research involving the engraftment of human neural stem cells into the brains of nonhuman primates are explored by an interdisciplinary working group in this Policy Forum. The authors consider the possibility that this research might alter the cognitive capacities of recipient great apes and monkeys, with potential significance for their moral status.

Some philosophers have argued that moral agency is characteristic of humans alone and that its absence from other animals justifies granting higher moral status to humans. However, human beings do not have a monopoly on moral agency, which admits of varying degrees and does not require mastery of moral principles. The view that all and only humans possess moral agency indicates our underestimation of the mental lives of other animals. Since many other animals are moral agents (to varying degrees), they (...) are also subject to (limited) moral obligations, examples of which are provided in this paper. But, while moral agency is sufficient for significant moral status, it is by no means necessary. (shrink)

Research with human–animal chimera raises a number of ethical concerns, especially when neural stem cells are transplanted into the brains of non-human primates . Besides animal welfare concerns and ethical issues associated with the use of embryonic stem cells, the research is also regarded as controversial from the standpoint of NHPs developing cognitive or behavioural capabilities that are regarded as “unique” to humans. However, scientists are urging to test new therapeutic approaches for neurological diseases in primate models as they better (...) mimic human physiology than all current animal models. As a response, various countries have issued reports on the topic. Our paper summarizes the ethical issues raised by research with human–animal brain chimeras and compares the relevant regulatory instruments and different recommendations issued in national reports from three important European research nations: Germany, Switzerland and the United Kingdom. We assess and discuss the focus and priorities set by the different reports, review various reasons for and perspectives on the importance of the brain in chimera research, and identify critical points in the reports that warrant further specification and debate. (shrink)

Human–nonhuman chimeras have been the focus of ethical controversies for more than a decade, yet some related issues remain unaddressed. For example, little has been said about the relationship between the origin of transferred cells and the morally relevant capacities to which they may give rise. Consider, for example, a developing mouse fetus that receives a brain stem cell transplant from a human and another that receives a brain stem cell transplant from a dolphin. If both chimeras acquire morally relevant (...) capacities as a result of transplantation, and if those capacities are indistinguishable, should the difference in cell origin matter to how we classify these creatures? I argue that if morally relevant capacities are easy to detect, cell origin is irrelevant to how the chimera ought to be treated. However, if such capacities are hard to detect, cell origin should play a role in considerations about how to treat the chimera. (shrink)

Animal models of human diseases are often used in biomedical research in place of human subjects. However, results obtained by animal models may fail to hold true for humans. One way of addressing this problem is to make animal models more similar to humans by placing human tissue into animal models, rendering them chimeric. Since technical and ethical limitations make neurological disorders difficult to study in humans, chimeric models with human neural tissue could help advance our understanding of neuropathophysiology. In (...) this article, we examine whether the introduction of human neural tissue and any consequent cognitive change is relevant to the way we ought to treat chimeras. We argue that changes in cognitive abilities are morally relevant to the extent that they increase the capacities that affect the moral status of any entity, including awareness, autonomy, and sociability. We posit that no being, regardless of species, should be treated in a way that is incommensurate with its moral status. Finally, we propose a framework that can be used to guide ethical assessment of research involving chimeras with advanced cognitive capacities. We advance this framework as a useful tool for bringing relevant considerations to the forefront for those considering the ethical merit of proposed chimeric research. In doing so, we examine concepts relevant to the question of how any entity may be treated, including moral status, dignity, and capacities. (shrink)

Did Descartes deny that animals can feel? While it has generally been assumed that he did, there has been some confusion over the fact that Descartes concedes to animals both sensations and passions'. John Cottingham, for example, has argued that while Descartes did insist that animals were automata, denying them thought and "self"-consciousness, none of these assertions entail the conclusion that animals do not feel. This paper examines both Cottingham's arguments and the relevant sections of Descartes' writings, concluding that Descartes (...) does indeed deny that animals are capable of feeling, but that for various reasons, this is not the brutal' and monstrous' view it is commonly assumed to be. (shrink)

This work was supported, in part, by a Stem Cell Network grant to Françoise Baylis and Jason Scott Robert and a CIHR grant to Françoise Baylis. We sincerely thank Alan Fine, Rich Campbell, Cynthia Cohen, and Tim Krahn for helpful comments on an earlier draft of this paper. Thanks are also owed to Tim Krahn for his research assistance. An earlier version of this paper was presented to the Department of Bioethics and the Novel Tech Ethics research team. We thank (...) the participants at each of these meetings for their helpful comments. (shrink)

This article discusses what is involved in having full moral status, as opposed to a lesser degree of moral status and surveys different views of the grounds of moral status as well as the arguments for attributing a particular degree of moral status on the basis of those grounds.