On my previous post regarding the ethical implications of epigenetics research, Aileen Kennedy provided a thoughtful comment on how this might relate to the concept of mind-body dualism. Instead of writing a short reply to Ms. Kennedy, I decided to devote a full blog post to how our developing understanding of epigenetics might alter how we think about the relationship between biology and identity.
Among modern philosophers, Descartes stands out for his elucidation of the Platonic concept of mind-body dualism. Descartes theorized that the body was simply like a machine and that what truly defined one's existence or true identity was the immaterial mind (recall his famous dictum: “cogito ergo sum—I think, therefore I am”) which controls the body. In other words, the body is simply a coalescence of flesh (like a mindless Golem) that has little to do with defining one's essence outside of purely material or aesthetic considerations.
Of course modern medicine and neuroscience have rejected this Cartesian notion that the mind is purely immaterial and not connected to any physical tissue. However, in its stead modern medicine has established its own mind-body dualism of neural tissue being the repository of our individual identity and the rest of our body being purely functionary but not defining our essence. Indeed, neuroscience has located different areas of the brain (e.g., the amygdala as the seat of emotion and social learning and the pre-frontal cortex for self-control and goal-setting) that can grossly said to be related to one's personality or identity. For instance, if someone has their frontal lobe damaged by physical trauma or prenatal exposure to alcohol, doctors can predict that person will exhibit problems with impulse controls among other issues.
Further, we can see this mind-body dualism manifested in a variety of ways, such as private cryogenics providers offering to freeze simply one's head but not the rest of the body (because the brain is all one really needs to preserve the immortality of one's existence) with the hope that this head can be reattached to a donor body in the future. We also see in it in modern bioethical regulations. Consider the UK's ban on allowing human-animal chimera embryos to develop past 14 days. http://news.bbc.co.uk/2/hi/health/6524883.stm Why 14 days you might ask? The reason is that shortly after 14 days in human embryos the primitive streak (beginning of spinal and brain tissue) starts to form and the differentiation of pluripotent stem cells into neural crest cells begins. The ethical argument is that before “generic” stem cells (which are actually unique in terms of their DNA) differentiate into neural cells, there is no potential for the putative organism to develop any individuality. Ergo, human individuality (identity) stems from neural tissue--other human (body/corporeal) tissue is irrelevant in this regard.
However, there has always been anecdotal evidence that non-neural cells can also exhibit “memory” or fundamental markers of one's unique identity. There are numerous case reports of heart transplant recipient all of a sudden being endowed with the artistic skills or peculiar dietary preferences of their deceased organ donors. In other words, the existential or lived experiences of the heart donor seems to have been imprinted upon their non-neural tissue and appears to be “talking to” to the cells in its new host body. Before one relegates this concept of “cellular memory” to sensationalist new-age hucksterism that one might find on daytime television (yes, I'm calling you out Oprah for giving credibility to “The Secret”) consider that Dr. Gary Schwartz of University of Arizona has documented 70 cases where transplant recipients have inherited fundamental personality traits of their donors (http://www.dailymail.co.uk/health/article-381589/The-art-transplant.html#ixzz13mkpSZg9).
While these case reports are not definitive proof that cellular memory exists, the concept that individual cells outside of our brain are indeed imprinted with our life's experiences seems more plausible with the epigenetics providing a demonstrable and logical mechanism of how this might occur.
Will this concept of non-neural tissue storing important information about one's individual, existential identity change normative considerations relating to organ donation, embryonic stem cell research, cry, etc? I honestly do not know, but I think it is interesting to pose this question and see what others think.(Khan)