Scientists in the United States have claimed to have developed something straight out of science fiction – a functioning human “mini-brain” contained in a petri dish. The brain is said to be equivalent of about a 5-week foetus. The hope is for the mini-brain to replace some animal experiments, providing a much better model of human neural activity.
The researcher presenting the findings, Rene Anand, claimed that the “ethical issues were non-existent”. But that is deeply mistaken – the development raises profound ethical questions, intersecting with animal rights, philosophy of mind and our conception of what it is to be human.
To say there are ‘ethical issues’ does not mean there are only problems with the development. On the upside, this not only promises to improve scientific validity of basic research, but could lead to less ethically questionable animal neurological research. While significant protections are in place for such research, it may still nevertheless involve killing animals, subjecting animals to considerable discomfort or pain. Currently, that may be justified by the potential benefits to humanity – but if a scientifically superior alternative such as human brains in petri dishes becomes available, it may become ethically impermissible (perhaps with legal reforms to follow) to perform traditional animal neurological research.
That having been said, we should attend to the potential ethical issues as well. Firstly, the cells originated from a human donor’s skin cells. This means that the brain is composed of the biological material of the donor’s. In normal cases, donors may not be terribly concerned with the disposition of those cells. But when they’re used to make a brain, do they become something more? Certainly, the skin cell donors should consent to the use of their cells specifically to make mini-brains (‘broad consent’ would probably not be appropriate in this case). And we might go further and question whether the donor can ever fully relinquish control over the brain cells, if we think their neural functioning in an important way make them still a proper part of the donor.
Moreover, we must carefully examine whether the ‘mini-brains’ are indeed conscious. If they are conscious, then a whole host of ethical worries arise. What sort of inner life are researchers subjecting to the mini-brain? Are they living lives of pain? Can they qualify as ‘human’ (given they are human cells and structured to function like a human brain), thereby inheriting various human rights? It may well be more problematic to experiment a petri dish brain with completely malformed consciousness processes than a relatively orderly animal brain.
Anand claims the mini-brains are not conscious, stating there are no sensory stimuli entering the brain and therefore it is not thinking. But in many strands of philosophy of mind (including Cartesianism and Monism) external stimuli are not necessary for thought to occur – sentience can be free-floating. And there is some evidence for this as well – consider “phantom pain”, where individuals who lost limbs nevertheless feel pain in those limbs. The origin of the pain is often not an external stimuli, but the person’s brain itself .
So evidence for consciousness may have come from attendance to the neural structure itself. Here, the fact that the brain in the petri dish is analogous to a 5-week-old foetus gives better indication that it is not conscious (given that at such a stage, foetuses are not generally thought to be sentient). However, we still run into the philosophical problem of other minds – scientists cannot directly observe consciousness, only infer it from correlations between neural activity and someone’s reports of being conscious (and even that is a questionable inference). And we cannot ask the petri dish whether it is conscious.
The great unknowns
We are really left with a situation where we do not know whether or not the brain in the petri dish is conscious, much less what kind of conscious life it could have. Before such research proceeds, then, we should engage neuroscientists and philosophers of mind to reduce that uncertainty. This is because while the uncertainty exists, research on brains in petri dishes is essentially very risky – a significant risk that we are creating beings with inner lives, and subjecting them to pain, despair, indignity and more ills besides.
The other great unknown is where this research will lead. Even if Anand is right and the present brain is not conscious, the research could lay a foundation that leads to the creation of a brain in a petri dish that certainly is conscious – e.g., resembling a much more developed foetus that is generally agreed upon to have consciousness. Should we ban such entities from ever being created? Can we stop the inevitable onwards rush of scientific development? Or should we allow them to be made, but ascribe to them the rights of fellow humans? But then, we may ask, what is the point of creating them in the first place – if they have all the rights of humans, then the same research protections as apply to humans would also be used and the research utility would be greatly diminished. Or will there be other reasons to create brains in petri dishes – e.g., as an alternative computer processor?
These questions cannot be answered in a mere blog post. But the fact that they are so uncertain, while developments progressing so rapidly, means that there is urgent need for deep, thoughtful, and public discussion of these issues so appropriate legal, social and regulatory regimes can be developed.