If there were one startling and apt image of today's Olympics it wouldn't be the five rings, let alone the uninspired logo for 2012. It would be the clean, sprung lines of the carbon-fibre blades used by amputees to run in the Paralympics and, now, in the conventional Olympics – a device entirely human in use and totally functional in form.
The Wellcome Foundation has one, a "Flex-foot Cheetah", made by Össur, in the middle of its new exhibition Superhuman: Exploring Human Enhancement from 600BCE to 2050. It should have put it at the centre.
Timed to coincide with the Olympics, the exhibition might well have concentrated simply on man's efforts to increase his athletic performance. Instead, it has taken its cue from the Paralympics to explore more generally the search to replace the deficient and increase the prowess of our mortal being.
It's a fascinating theme not just for its mechanics but its ethics. At the beginning, the efforts of medicine and craft were bent on replacing lost parts. The earliest object displayed is an artificial toe that was buried with an Egyptian mummy and turned out, on examination, to be not symbolic but a false digit actually used and demonstrably workable. Artificial legs, false eyes, spectacles and porcelain dentures soon follow as the search for the functional expanded to the improvement of appearance. Breast enhancement takes its place, woollen knit as well as silicone implant, along with the "Waterloo teeth" taken from the dead (we hope) on the battlefield.
Sex, too, rears its frolicsome head with a charming little 19th-century Indian gouache of "a Woman using a dildo in the form of a root vegetable suspended from the branch of a tree" and an 18th-century "Ivory dildo in the form of an erect penis, complete with contrivance for simulating ejaculation" of a size that would have done credit to a Siberian mammoth, never mind a mere human.
Rather touchingly we are told that a silver false nose made for a syphilitic woman was later returned when she married and found her husband preferred her without it.
Contemporary artists take all of this with a certain wryness. There's an entrancing video by Regina Jose Galindo, Recorte por la Linea (Cut Through the Line), filmed in Venezuela, which apparently has the highest rate of aesthetic procedures per capita in the world. In it, the artist has her body marked up by a surgeon detailing just where and how each curve can be improved. The German artist Rebecca Horn goes in the other direction with a series of contraptions to enhance the reach of head and hand.
The men are no less subject to the idea of the perfect physique, of course, with the Atlas courses in body building, taken on a few steps by the female bodybuilder and video artist, Francesca Steele. Superhero comics make the muscular magnificent as well as menacing. Matthew Barney, the American filmmaker, directed a whole series of Cremaster stories around the figure of the double amputee model and Paralympian, Aimee Mullins, taking various half-animal, half-machine roles.
It's not all vanity and competitiveness. Lest we take prosthetics too light-heartedly, the curators also include a moving section on thalidomide children, when the company and the state attempted to make up for the appalling malformation of thalidomide births by providing expensive and cumbersome false limbs to make the children more normal, only to find that, less interested in appearance than mobility, they preferred electric wheelchairs or using their feet to feed themselves.
Any human intervention raises questions of what is permissible and what is not. The exhibition begins, as it ought, with the figure of Icarus, the youth who was given wax-worked wings and soared too close to the sun and crashed to earth. Man must strive but also accept his limitations. The Olympic Games, as the show records, started without any ban on enhancement drugs and saw several disastrous collapses of the overstrained runners. The Tour de France, a test of endurance as much as skill, was rife with drugs, with a string of deaths resulting (one fatal collapse is captured on camera and exhibited in the show).
There are those who argue that technology and drugs are actually egalitarian. Available to all they will iron out disparities in physique and give everyone a chance, just as there are those that argue "blades" give the amputee unfair advantages over those with conventional limbs.
Wellcome wrestles with these questions as it presents a contemporary world in which technology, biology and medicine are all melding into each other. The "i-limb" displayed has independently driven fingers operated by electrical impulses controlled by muscle contractions. So effective is it that some have chosen to have their hand amputated rather than labouring with a half-way house. Implanted chips can remotely control machines. Revital Cohen has erected a machine, "The Immortal", in which life-support machines connect to each other in a display of how human organs can be replicated mechanically. And, if you want to think harder on the questions posed by this futuristic world, there are a series of talking heads discussing transhumanism and enhancement.
"The conversation with society has changed profoundly in this last decade," Mullins says. "It is no longer a conversation about augmentation, it's a conversation about potential. A prosthetic limb does not represent the need to replace loss anymore. It can stand as a symbol that the wearer has the power to create whatever it is that they want to create in that space, so that people society once considered disabled can now become the architects of their own identity."
Maybe. But then there's a nagging question, which the exhibition fails to ask, about who will control and disburse these costly products of man's endless drive towards self-enhancement. A conference of the US National Science Foundation written up on the last wall concludes with a prediction for 2025 that "robot and software agents will operate on principles compatible with human goals, awareness and personality". It would fly in the face of history if they did.
Superhuman, Wellcome Collection, London NW1 (020 7611 2222) to 16 October