How science has shifted our sense of identity

Across the arc of the past 150 years, we can see both science and scientism shaping human identity in many ways. Developmental psychology zeroed in on the intellect, leading to the transformation of IQ (intelligence quotient) from an educational tool into a weapon of social control. Immunology redefined the ‘self’ in terms of ‘non-self’. Information theory provided fresh metaphors that recast identity as residing in a text or a wiring diagram. More recently, cell and molecular studies have relaxed the borders of the self. Reproductive technology, genetic engineering and synthetic biology have made human nature more malleable, epigenetics and microbiology complicate notions of individuality and autonomy, and biotechnology and information technology suggest a world where the self is distributed, dispersed, atomized.

Individual identities, rooted in biology, have perhaps never played a larger part in social life, even as their bounds and parameters grow ever fuzzier.

Designs on intelligence

“Methods of scientific precision must be introduced into all educational work, to carry everywhere good sense and light,” wrote the French psychologist Alfred Binet in 1907 (English translation published in 1914 (ref. 2)). A decade earlier, Binet and Théodore Simon developed a series of tests for French schoolchildren to measure what they called ‘mental age’. If a child’s mental age was less than her chronological age, she could receive extra help to catch up. The German psychologist William Stern took the ratio of mental to chronological age, giving what he called the IQ and, theoretically, making it comparable across groups. Meanwhile, Charles Spearman, a British statistician and eugenicist of the Galton school, found a correlation between a child’s performance on different tests. To explain the correlations, he theorized an innate, fixed, underlying quality he called ‘g’, for ‘general intelligence’. Then the American psychologist Henry Goddard, with the eugenicist Charles Davenport whispering in his ear, claimed that low IQ was a simple Mendelian trait. Thus, step by scientistic step, IQ was converted from a measure of a given child’s past performance to a predictor of any child’s future performance.

IQ became a measure not of what you do, but of who you are — a score for one’s inherent worth as a person. In the Progressive era, eugenicists became obsessed with low intelligence, believing it to be the root of crime, poverty, promiscuity and disease. By the time Adolf Hitler expanded eugenics to cover entire ethnic and cultural groups, tens of thousands of people worldwide had already been yanked from the gene pool, sterilized, institutionalized, or both.

Immunologists took another approach, They located identity in the body, defining it in relational rather than absolute terms: self and non-self. Tissue-graft rejection, allergies and autoimmune reactions could be understood not as a war but as an identity crisis. This was pretty philosophical territory. Indeed, the historian Warwick Anderson has suggested that3 in immunology, biological and social thought have been “mixing promiscuously in a common tropical setting, under the palm trees”.

Not me

The immunological Plato was the Australian immunologist Frank MacFarlane Burnet. Burnet’s fashioning of immunology as the science of the self was a direct response to his reading of the philosopher Alfred North Whitehead. Tit for tat, social theorists from Jacques Derrida to Bruno Latour and Donna Haraway have leaned on immunological imagery and concepts in theorizing the self in society. The point is that scientific and social thought are deeply entangled, resonant, co-constructed. You can’t fully understand one without the other.

Later, Burnet was drawn to new metaphors taken from cybernetics and information theory. “It is in the spirit of the times,” he wrote in 19544, to believe there would soon be “a ‘communications theory’ of the living organism.” Indeed there was. In the same period, molecular biologists also became enamoured of information metaphors. After the 1953 solution of the DNA double helix, as the problem of the genetic code took shape, molecular biologists found analogies with information, text and communication irresistible, borrowing words such as ‘transcription’, ‘translation’, ‘messengers’, ‘transfers’ and ‘signalling’. The genome ‘spells’ in an ‘alphabet’ of four letters, and is almost invariably discussed as a text, whether it is a book, manual or parts list. Not coincidentally, these fields grew up alongside computer science and the computing industry.

The postwar self became a cipher to be decoded. DNA sequences could be digitized. Its messages could, at least in theory, be intercepted, decoded and programmed. Soon it became hard not to think of human nature in terms of information. By the 1960s, DNA was becoming known as the ‘secret of life’.

Many selves

In the late 1960s and 1970s, critics (including a number of scientists) grew concerned that the new biology could alter what it means to be human. The ethical and social issues raised were “far too important to be left solely in the hands of the scientific and medical communities”, wrote James Watson (of DNA fame and later infamy) in 1971.

In 1978, Patrick Steptoe and Robert Edwards succeeded with human in vitro fertilization, leading to the birth of Louise Brown, the first ‘test-tube baby’. By 1996, human cloning seemed to be around the corner, with the cloning of a sheep that Ian Wilmut and his team named Dolly.

Cloning and genetic engineering have prompted much soul-searching but little soul-finding. There has long been something both terrible and fascinating about the idea of a human-made, perhaps not-quite-person. Would a cloned individual have the same rights as the naturally born? Would a baby conceived or engineered to be a tissue donor be somehow dehumanized? 

Do we have a right to alter the genes of the unborn? Or, as provocateurs have argued, do we have an obligation to do so? The recent development of potent gene-editing tools such as CRISPR has only made widening participation in such decision-making more urgent.

Arguments, both pro and con, around engineering humans often lean on an overly deterministic understanding of genetic identity. Scientism can cut both ways. A deep reductionism located human nature inside the cell nucleus. In 1902, the English physician Archibald Garrod had written5 of genetically based “chemical individuality”. In the 1990s, as the first tsunamis of genomic sequence data began to wash up on the shores of basic science, it became obvious that human genetic variation was much more extensive than we had realized. Garrod has become a totem of the genome age.

By the end of the century, visionaries had begun to tout the coming of ‘personalized medicine’ based on your genome. No more ‘one size fits all’, went the slogan. Instead, diagnostics and therapy would be tailored to you — that is, to your DNA. After the Human Genome Project, the cost of DNA sequencing nosedived, making ‘getting your genome done’ part of mass culture.

Today, tech-forward colleges offer genome profiles to all incoming first-years. Hip companies purport to use your genome to compose personalized wine lists, nutritional supplements, skin cream, smoothies or lip balm. The sequence has become the self. As it says on the DNA testing kit from sequencing company 23andMe, “Welcome to you.”

Boundaries blur

But you are not all you — not by a long shot. The DNA-as-blueprint model is outdated, almost quaint.

For starters, all of the cells in a body do not have the same chromosomes. Cisgender women are mosaics: the random inactivation of one X chromosome in each cell means that half a woman’s cells express her mother’s X and half express her father’s. Mothers are also chimaeras, thanks to the exchange of cells with a fetus through the placenta.

Chimaerism can cross the species boundary, too. Human–chimpanzee embryos have been made in the laboratory, and researchers are hard at work trying to grow immune-tolerant human organs in pigs. Genes, proteins and microorganisms stream continuously among almost any life forms living cheek by jowl. John Lennon was right: “I am he as you are he as you are me and we are all together.”

Even in strictly scientific terms, ‘you’ are more than the contents of your chromosomes. The human body contains at least as many non-human cells (mostly bacteria, archaea and fungi) as human ones6. Tens of thousands of microbial species crowd and jostle over and through the body, with profound effects on digestion, complexion, disease resistance, vision and mood. Without them, you don’t feel like you; in fact, you aren’t really you.

The biological self has been reframed as a cluster of communities, all in communication with each other.

These, too, cavort promiscuously beneath the palms. Scientists found that they could use a person’s microbiome to identify their sexual partner 86% of the time7. The communities of greatest similarity in cohabiting couples, they found, are on the feet. The thigh microbiome, by contrast, is more closely correlated with your biological sex than with the identity of your partner.

A body part, a cesspool, a subway car, a classroom — any place with a characteristic community — can be understood as having a genetic identity. In such a community, genetic information passes within and between individual organisms, through sex, predation, infection and horizontal gene transfer. In the past year, studies have shown that the communities of symbiotic microbes in deep-sea mussels become genetically isolated over time, like species. In fungi, genes called Spok (spore-killer) ebb and flow and recombine across species by ‘meiotic drive’, a kind of genomic fast-forward button that permits heritable genetic change to occur fast enough to respond to a rapidly changing environment. The genome, as the geneticist Barbara McClintock said long ago, is a sensitive organ of the cell.

Epigenetics dissolves the boundaries of the self even further. Messages coded in the DNA can be modified in many ways — by mixing and matching DNA modules, by capping or hiding bits so that they can’t be read, or by changing the message after it’s been read, its meaning altered in translation. DNA was once taught as a sacred text handed faithfully down the generations. Now, increasing evidence points to the nuclear genome as more of a grab bag of suggestions, tourist phrases, syllables and gibberish that you use and modify as needed. The genome now seems less like the seat of the self and more of a toolkit for fashioning the self. So who is doing the fashioning?

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