A team of scientists led by Nenad Sestan (Yale) have “restored circulation to the brains of decapitated pigs and kept the reanimated organs alive for as long as 36 hours,” reports MIT Technology Review. The method used to keep pigs’ brains alive outside the body will work on other animals, including primates, Sestan said. The following is a guest post* by Carolyn Dicey Jennings, assistant professor of philosophy and cognitive science at UC Merced, in which she discusses some of the philosophical issues arising from this research.

Resurrecting Brains: Philosophical Questions and New Ethical Territory
by Carolyn Dicey Jennings

Let’s say for argument’s sake that you have a decapitated pig and you are wondering whether you should bring its brain back to life. What ethical issues might concern you? Some brain researchers have been thinking about this and they have a request: “The researchers say that ways of measuring consciousness need to be developed and strict limits set for them to be able to continue their work with the public’s support.” Here are some ideas, but I would like to hear from other philosophers in the comments:

1. Self

If you are going to bring a pig’s brain back to life for scientific experimentation, you probably want to know whether you have also brought back a self. This will be especially problematic when the research is extended to human brains and selves, which is already on the horizon. Of course, some would argue that there are no such things as selves, but I disagree.

Do pigs have selves? They have not yet passed the mirror self-recognition test, which is used by many as a marker of the self. This test requires that an animal recognize its reflection in a mirror as its own. Passing the test is, in normal cases, impressive—a sign of high intelligence, at the very least. Does failing to pass the test indicate an absence of self? No. That bar is too high. Toddlers often don’t pass the test, but ask those who have spent time with toddlers if they have a self. (Hint: yes.)

What these toddlers and many other animals lack is self-consciousness—-an understanding of themselves as selves. Without self-consciousness how could you know that something has a self? Perhaps having a distinctive personality is one sign of self, which pigs certainly display. But disembodied pig brains probably don’t have easily measurable personalities. So what can we do to rule out the presence of a self in a disembodied brain?

One possibility is to rule out the presence of hierarchical frequency coupling. The brain has measurable wave patterns that are cheap and relatively easy to detect through the use of EEG. As I argue in a book under contract with Cambridge University Press, the self is active when low-frequency waves modulate high-frequency waves. So one suggestion is that researchers look for this signature of the self before proceeding with further experimentation.

2. Consciousness

Separate from the issue of the self is that of consciousness—are disembodied pig brains capable of consciousness? This is a hard question. I am teaching a course on consciousness right now and my students have commented on how difficult it is to determine consciousness in nonhuman cases, such as animals and machines, but few think consciousness is absent in animals. One issue is that of language: nonhuman animals have limited to no language, whereas machines have only superficial language abilities (think Chinese Room, or its modern equivalent). It is difficult to discover if something or someone is conscious if you cannot ask them.

Luckily, a number of promising neural markers of consciousness that do not rely on language have been put forward. One is that of feedback from the frontal cortex, likewise measured using EEG. Unlike many animals, pigs do have a frontal cortex, and thus frontal feedback—signals from the frontal cortex to other parts of the brain. (It is called “feedback” because brain processing is normally considered to go from other areas of the brain “forward” to the frontal cortex, and then back again.) If the disembodied brains of pigs display frontal feedback then I think consciousness is a very real possibility.

Another option is to look at the brain’s response to direct stimulation; brains of conscious humans tend to have widespread activation after direct stimulation, whereas brains of unconscious humans do not. This would be a fairly easy test that would help us to look for consciousness in parts of brains or in animals that do not have a frontal cortex.

An advantage of this latter method is that it might capture low-level consciousness, whereas frontal feedback captures only high-level consciousness. Consider this — the difference between standard and so-called “lucid” dreaming is that lucid dreamers report being aware of the fact that they were dreaming. This ability has been found to correspond with greater frontal cortex activity. But surely one need not be a lucid dreamer to be conscious while dreaming (pace Dennett). So frontal feedback may add the awareness that we are conscious, but the absence of frontal feedback would not necessarily mean an absence of consciousness.

3. Pain

A major topic in research ethics is that of pain; causing unnecessary pain and suffering is to be avoided, and this informs current practice. Can we feel pain without a body? One reason to think otherwise is that pain is attributed to parts of the body that signal damage to the brain through the spinal cord. With neither a body nor spinal cord what pain is there to feel? Is whole-body phantom pain possible?

We don’t yet know what happens to a brain without a body. Scientists and philosophers have argued that many forms of consciousness are either partly or wholly dependent on a body. It would be difficult to test for the presence of pain in a disembodied brain because its neural correlates also register non-painful stimuli.

I don’t have a good suggestion for this issue. (I am hoping others do!) The best idea I have had is to start by looking more closely at dreams during NREM sleep. This is the type of sleep we have without even activity in the eyes, when the whole body is at rest. Those woken up during NREM sleep sometimes report dreams. Further exploration here may give us insight into what experience without a body might look like, and whether it could include pain and suffering.

4. New Ethical Territory

I do think that this research is new ethical territory for us. We already allow scientific experimentation on animals that are likely to have consciousness, selves, and sometimes pain. The difference in this case is that these animals (well, brains) are being brought back to life having already experienced death. This may sound absurd, but if the dying brain hypothesis is correct, many of the sacrificed pigs will likely have had near death experiences (i.e. walking in a tunnel toward the light, euphoria, etc.). What will happen when they are brought back? We don’t know. We don’t know if it will cause needless suffering, and thus we don’t know if this work warrants special protections and guidelines. Creating brains in the lab (which is also on the research agenda, and has its own issues) seems importantly distinct from ending, restarting, and re-ending the lives of conscious beings with histories. This is especially true when the beings in question are disembodied brains, which cannot easily communicate the stress or suffering they might be enduring.

art: Wim Delvoye, Pigs