The idea that we should use technology to transcend the limitations of the human body and brain was dubbed "transhumanism" by the biologist Julian Huxley, brother of Aldous. Huxley believed that "the human species can, if it wishes, transcend itself" through an "evolutionary humanism." But transhumanism, improving on the human form and not just our social institutions, was implicit in the Enlightenment from its beginning, from Denis Diderot, Jean de Condorcet, William Godwin and Robert Boyle to Benjamin Franklin and Tom Paine.
In 1769, Diderot, editor of the Encyclopédie, wrote three whimsical essays known as "D'Alembert's Dream" recounting imaginary dialogues between himself, his friend d'Alembert, a cultured lady friend, and a physician. In these dialogues Diderot proposes that, since human consciousness is a product of brain matter, the conscious mind can be deconstructed and put back together. Science will bring the dead back to life. Animals and machines can be redesigned into intelligent creatures, and humanity can redesign itself into a great variety of types "whose changes and whose future and final organic structure it's impossible to predict."
It seems likely that this century will see Diderot's prescience confirmed. In the coming decades, as pharmacology, artificial intelligence, nanotechnology, and biotechnology converge, life spans will extend well beyond a century. Our senses will extend to perceive sights, sounds and sensations beyond our current abilities. We will remember more of our lives, with greater fidelity. We will master fatigue, arousal and attention, and give ourselves more working intelligence. We will have greater control over our emotions, and be less subject to depression, compulsion and mental illness.
Our bodies and brains will be surrounded by and merged with computer power which itself will become as, or more, powerful than our brains. As we merge machines into our minds we will indeed be deconstructed and put back together. We will use these technologies to redesign ourselves, our children and animals, into varieties of intelligent life impossible to predict.
For the last three hundred years, the idea that humans should take creative responsibility to improve the works of the Intelligent Designer, whether monarchies or reproductive biology, has been resisted by religious conservatives, political authoritarians and romantic defenders of an idyllic past. In today's debate over the future of human evolution these diverse voices from left and right have joined in a bioconservative alliance to oppose life extension and human enhancement technologies. For bioconservatives attempts to acquire radically longer lives, healthier bodies or quicker brains are hubristic flights from God, consumer capitalist false consciousness, neo-eugenic Brave New World-ism or Faustian pacts with the techno-industrial age. For these critics of the Enlightenment becoming more than human threatens "human dignity" and is doomed to disaster.
As Diderot prefigured, central to this emerging biopolitics is the debate over whether mind is unique to human beings, whether "human" is a meaningful moral category. For Enlightenment partisans mind is an emergent property of matter, and "human" is a constantly evolving category with indistinct borders. Our accidental gift of mind is shared to various extents with our mammal cousins and recent ancestors. If we and our fellow citizens make ourselves more than human, wherever that line might lie, and if our society is joined by intelligent animals or machines, this would not be an untenable abomination but an enrichment of our diversity. Bioconservatives reject this future diversity since only humans can have rights, and our culture and polity depends on human-racial unity and purity.
Between the distracting extremes of naïve techno-utopianism and bioconservative bans on emerging technologies there are many legitimate questions about the risks of tinkering. One challenge is to ensure that access to enhancement technologies is widely distributed so that we are not fractured by the emergence of an enhanced elite. Universal access to enhancement may seem impossible in our grossly unequal world. But there are grounds for optimism.
Some enhancement technologies will probably be cheap. Gene therapies or pharmaceuticals to suppress aging and repair the body and brain could be as inexpensive to distribute as condoms, mosquito nets and vaccines. Of course, though within reach, the world's poor don't yet have the condoms, mosquito nets and vaccines they need, so it can seem perilously foolish to propose that they have a right to life extension and brain boosters. Yet, ten years ago, when anti-retroviral therapies for HIV cost $40,000 a year, it was inconceivable that we would now have billions of dollars in a Global Fund to make those therapies available to people living on a dollar a day. The response to the challenge of global access to HIV treatment was not to ban antiretrovirals in the North, but to force pharmaceutical companies to accommodate humanitarian need, to develop cheaper therapies, and to invest in the health systems of the South. We will need the same policies to ensure access to enhancement technologies, from $100 laptops to gene therapies to cybernetic implants.
Even if enhancement therapies aren't cheap, their social benefits will generally make them cost-effective. Diderot bids d'Alembert goodnight by saying "Give a man, I don't say immortality, but only twice his lifespan, and you'll see what'll happen." As the Baby Boomers pass into their seventies in the developed countries, with shrinking numbers of children taking their place in the workforce, our health care and pension systems will stagger. If aging-related diseases and disabilities can be postponed by therapies that slow aging and repair the brain the graying of society will be far less traumatic. Spending one or two percent more of the GDP to develop anti-aging therapies and guarantee their universal accessibility would then be an overall economic necessity.
Similarly, the burdens of cognitive deficits such as dementia, addiction, and mental illness will make universal access to cognitive enhancement therapies an obvious choice. Yet these same neurotechnologies also have grave risks. In Diderot's dialogues his sleeping friend d'Alembert muses that human beings could devolve into "large, inert, and immobile sediment." In other words we could, through accident or intention, lose faculties we value, such as our capacities for empathy, creativity, awe or calm reflection. Some addictive drugs, like methamphetamine, rewire the brain to focus on only the next fix, while hormones and neurotransmitters can manipulate our feelings and interests. We need guidelines and policies to steer human evolution away from dead ends of radical selfishness and addictive absorption, and towards greater sociability, self-awareness and reason. Even self-chosen brain engineering could make us all less than human, and we need instead to encourage one another to enhance the virtues that we value.
Diderot's third dialogue addresses another bioconservative anxiety, the hybridization of humans and animals. Blurring the line between humans and animals violates deep taboos, stirring visions of the Minotaur and the Island of Dr. Moreau. U.S. President Bush and the Church of Scotland have both called for a ban on hybrids. Such a ban would profoundly harm biomedical research, which uses animals with human genes and tissues to explore cures for many diseases.
There is, however, also a legitimate concern in human-animal hybrid research. At what point do hybrids acquire human level rights? D'Alembert's physician proposes the creation of a race of goat-men to liberate humans from drudgery. But why would it be more moral to enslave goat-men any more than other humans? Perhaps Diderot anticipated this objection since the final line in the dialogue notes that a French Cardinal had proposed to baptize an orangutan if only it would speak.
In fact the Spanish government is about to extend fundamental "human rights" laws to include great apes. Opponents argue that apes should not have rights because they do not display human levels of thought and culture. So what if apes were given human-level mental faculties through genetic engineering? Would there still be any objections to full enfranchisement? Now that we have the full genomes of humans and apes sequenced, and have identified the key genetic differences that differentiate our brains, this is an imminent possibility. The moral status of such an ape would be one of the starkest lines dividing the human-racists from the Enlightened.
Diderot also proposes the possibility of a sentient and living keyboard, a clavichord that might reproduce. While Diderot appears untroubled by the prospect, of all the risks posed by emerging technologies emergent machine minds are perhaps the greatest. In Diderot's dialogue the cultured lady suggests that, as the mind is connected by nerves to the body, all minds are connected to one another and the rest of the universe through sensitive fibers like a giant spider's web. The doctor responds that if minds that expansive were to exist there would be "an epidemic of good and evil geniuses" and "the constant laws of nature would be interrupted by natural agents." The capacity for apocalyptic chaos from self-willed intelligence rising out of our exponentially accumulating web of machines surely rivals the risks of climate change and bioterrorism. Staying ahead of this potentially apocalyptic "Singularity" will require that we merge with our web, our exocortex, spreading our minds across multiple bodies and machines, to become smarter and faster, to remain the web's weavers and not its ensnared victims.
If we defend liberal society and use science, democratic deliberation and prudent regulation to navigate these challenges, we have a shot at an inconceivably transcendent future, where we leave behind this pupal stage of humanity. Dreaming d'Alembert imagines humanity splitting apart to form separate cocoons, each distilling particular human traits - magistrates, philosophers, poets - and each birthing its own distinct butterflies. "Who knows what new race could result some day from such a huge heap of sensitive and living points?" We can become a new species of great diversity, united in fraternité by our shared appreciation of the preciousness of self-awareness in a vast, dark universe. This is the positive vision of the Enlightenment, each of us reaching our fullest technologically enabled potentials while living as one tolerant, abundant, democratic society.
Still, the skeptic asks, to what end? Why risk the path to posthumanity? What projects would we pursue with our immortal bodies, boundless minds, and sublime senses? Just as our Paleolithic ancestors could not have anticipated our great cities, our arts and machines, or our spiritual traditions, so we cannot now imagine the grandeur of the accomplishments of our posthuman descendents. The cultured lady in the dialogue imagines taking apart the mind of a genius for storage, and then reconstructing it later to see " memory, comparison, judgment, reason, desires, aversions, passions, natural aptitude, and talent reborn." Perhaps our descendents will use nanotechnology to turn whole planets into intelligent, living stuff, each atom a processor in a planet-sized mind, conscious of the fall of every sparrow and capable of preserving the memories of every life. In such a world our personal identities could continue for billions of years.
When D'Alembert wakes he asks "if everything is a universal flux, as the panorama of the universe demonstrates to me everywhere, what would the changes in a time span of a few million centuries produce here and elsewhere? Who knows what a thinking, feeling being is on Saturn?" Perhaps our descendents will reach out to find the other far-scattered forms of intelligence in our galaxy, and begin engineering the universe to stop its racing expansion to heat death. Or, as Michio Kaku suggests, perhaps they will build a new, more congenial universe and migrate there.
Whatever our descendents' projects they – and perhaps some of us - will look back on our lives today with the wonder, pity and gratitude that we feel for our Paleolithic ancestors. As our ancestors left their caves to build farms and cities, we must now take conscious rational control of our biological destiny and grow to reach the stars.