This paper critically examines the biology of species identity and the morality of crossing species boundaries in the context of emerging research that involves combining human and nonhuman animals at the genetic or cellular level. We begin with the notion of species identity, particularly focusing on the ostensible fixity of species boundaries, and we explore the general biological and philosophical problem of defining species. Against this backdrop, we survey and criticize earlier attempts to forbid crossing species boundaries in the creation (...) of novel beings. We do not attempt to establish the immorality of crossing species boundaries, but we conclude with some thoughts about such crossings, alluding to the notion of moral confusion regarding social and ethical obligations to novel interspecies beings. (shrink)

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.

_Real Essentialism_ presents a comprehensive defence of neo-Aristotelian essentialism. Do objects have essences? Must they be the kinds of things they are in spite of the changes they undergo? Can we know what things are really like – can we define and classify reality? Many, if not most, philosophers doubt this, influenced by centuries of empiricism, and by the anti-essentialism of Wittgenstein, Quine, Popper, and other thinkers. _Real Essentialism_ reinvigorates the tradition of realist, essentialist metaphysics, defending the reality and knowability (...) of essence, the possibility of objective, immutable definition, and its relevance to contemporary scientific and metaphysical issues such as whether essence transcends physics and chemistry, the essence of life, the nature of biological species, and the nature of the person. (shrink)

Research that involves the creation of animals with human-derived parts opens the door to potentially valuable scientific and therapeutic advances, yet invokes unsettling moral questions. Critics and champions alike stand to gain from clear identification and careful consideration of the strongest ethical objections to this research. A prevailing objection argues that crossing the human/nonhuman species boundary introduces inexorable moral confusion (IMC) that warrants a restriction to this research on precautionary grounds. Though this objection may capture the intuitions of many who (...) find this research unsettling, it relies on mistaken views of both biology and moral standing, ultimately distorting the morally relevant facts. We critically examine IMC, identify mistaken essentialist assumptions, and reframe ethical concerns. The upshot is a stronger line of objection that encourages a more inclusive and productive ethical discourse. (shrink)