FROM Medusa with her head of writhing snakes, to the priapic satyrs and the imprisoned and vengeful Minotaur, classical mythology abounds with strange part-human creatures.
These hybrid beings are rarely friendly, coming from the murky shadows of nightmare to disturb our sunlight world.
The source of the fear seems to be in the transgression they represent: the implication of inter-species sexual relations and, more profoundly, the breaking down of barriers between animal and human.
We humans like to see ourselves as fundamentally different from the other animals that share our wondrous and fragile planet.
In some ways, perhaps we are. As far as we know at least, we are the only creatures capable of articulating the ethical conundrums around our existence.
Mind you, a glance at the news headlines on any given day makes it clear the capacity for ethical thought is not inevitably linked to actual ethical behaviour.
Are humans morally superior to elephants? The elephants might not think so.
Human cognitive capacities are the philosophical underpinning for what we consider to be our higher moral status, a status that makes us consider a human life to be of more value than an animal one.
So perhaps it’s not surprising ethical discussions around the creation of a new wave of technologically mediated human–animal hybrids focus largely on the potential impact of human neurons in their brains.
Might a hybrid with human neuronal structures be more aware of their situation, have more potential for the kind of existential suffering we consider unique to humans?
And would the creation of such hybrids therefore raise fundamentally different moral questions from those raised by other human uses of animals?
Creating human–pig hybrids could be a way to address the shortage of organs for transplantation, allowing us to grow organs on demand, potentially using the recipient’s own stem cells to avoid rejection risk.
Actual transplantations may still be a way off, but CRISPR technology has already been successfully used to graft human stem cells into pig embryos, and debate about the ethics of such procedures has been going on for a while.
With organ generation using hybrid animals “on the cusp of feasibility,” we need to broaden the conversation, two bioethicists write in the Journal of Medical Ethics.
A widespread ethical concern raised about farming of human–pig chimeras for their organs is that their humanised brains might develop “morally relevant cognitive capacities”, the bioethicists write.
The uncertain moral status of hybrid animals has been widely discussed, with some arguing we should not create any chimeras with human-like neuronal structures for fear they might also develop human-like consciousness.
These two authors go further. If the moral status of a human–pig hybrid is uncertain, they argue, so is that of the non-chimeric pigs farmed for human consumption.
“It is difficult to assess the cognitive abilities of pigs,” they write. “Since we cannot communicate with pigs directly, we are limited to drawing inferences from pig behaviour and physiology.”
New ethical challenges raised by genetic technologies can shine a bright, perhaps unwelcome, light on gaps in our existing ethical frameworks.
For millennia, humans have fallen back on the assumption that we are more than animals, that we alone among the earth’s species have moral status.
The essential elements of that status, though, have always been hard to pin down: we have not determined “what set of cognitive capacities are morally relevant”, as these authors put it.
Many of the qualities we might put forward have, after all, been demonstrated in various other animals: grief at the death of a loved one, consciousness of self, and so on.
Even if we could agree on the precise mix that qualifies for the higher moral status tag, how would we go about testing for it “in creatures that look very different to us, that behave in very different ways and that we cannot communicate with directly”, these authors ask.
It’s a good question, though one that may be beyond our capacity to answer.
Jane McCredie is a Sydney-based science and health writer.
The statements or opinions expressed in this article reflect the views of the authors and do not represent the official policy of the AMA, the MJA or InSight+ unless so stated.