It's got the head of a monkey and the body of a monkey. But not the same monkey.

You probably don't want to hear any more details of this Mondo Bizarro medical news item. According to pioneering scientist Robert White, the mix-and-match creature he fabricated in a 1970s experiment survived for "many days." This experiment raised hopes, he told the BBC in an interview last month, because "People are dying today who, if they had body transplants...would remain alive."

This comment raises the bar in the competition for stating the obvious. Nevertheless, for most of us, the idea of swapping monkey heads prompts an immediate, instinctive revulsion, a reaction that may also feature incredulous laughter. Between those two reactions--this is too hideous to consider, this is too absurd to consider--there remains a stubborn reality: Somebody somewhere did consider it, and then went ahead and did it. In a lab somewhere, monkeys were beheaded, reassembled, and then kept temporarily alive.

The advancing front of the "life sciences"--cloning, gene manipulation, tinkering with body parts--keeps sending similar unbelievable and appalling items our way. Medical ethicists are regularly convened to fret about them, and on a recent TV show an audience member asked the panel the old familiar question: "Has our ability to produce these new technologies outdistanced our ability to cope with them ethically?"

The question has a weary quality, because we suspect that ethical concerns are going to have very little influence over what eventually takes place. It's efficiency, or the illusion of it, that governs these things. Look for comparison to the field of weapons development, where new killing devices have historically been implemented as soon as they are invented: the guillotine replacing the axe, for example. Hand-wringing about ethics seems irrelevant. Weapons technology hurtled forward until the proliferation of nuclear missiles brought the promise of Mutually Assured Destruction, and people realized no one would be around to enjoy this absolute efficiency. That glimpse into the abyss, rather than newfound scruples, prompted a pullback from the brink.

So the short answer to the woman in the audience is, Lady, that happened a long time ago. The human tendency to let technology overrun ethics appeared the first time somebody picked up a rock and hit somebody else over the head with it.

There's an extra creep factor with these new experiments, though. We've long been familiar with technologies that increase the efficiency of death. This latest round, however, confronts us with technologies that bring to life things we instinctively sense should not be. They feel disturbing and ominous, as if they violate the harmony of nature. Even when they engineer life, they participate in death.

Yet it's a disservice to dismiss these innovators as merely lacking in ethics. Dr. Joseph Guillotin was troubled by the clumsy and gruesome axe beheadings that he witnessed during the French Revolution, and the machine he proposed was welcomed as more compassionate. To a culture awash in blood the guillotine seemed an obvious improvement. Today, however, we would question whether factory-style decapitation ever advances social reform.

Similarly, Robert White, the monkey doctor, says that he was moved by the plight of people with severe spinal injuries. It seemed to him that a "body transplant" was the ideal solution. Once he started thinking about it, the idea became no stranger than a liver transplant.

How do you overcome instinctive revulsion at bizarre new technology? Just think about it long enough. Gradually, the strange and horrible comes to seem noble and benign, especially if it is more efficient. Too many drooling old people? Euthanasia can erase their embarrassing presence. Too many Down's syndrome babies? Track 'em down and snuff 'em before they're born. Quadriplegics fading away? Maybe decapitating them, then sewing on a fresh headless body, would give them a new lease.

Against this principle of vigorous efficiency, we have only the defense that we "instinctively sense" when things are going too far. That standard seems vague, but not because it lacks firmness and authority; rather, it is because it is being communicated to us from a place we don't regularly consult. We don't know how to hear this voice reliably. It's our ability to perceive or receive these convictions that is cloudy, not the convictions themselves.

This voice is related to conscience, another human capacity that is persistent and firm, yet can be overcome by reluctance, confusion, or rationalizing. Rationalizing in the name of efficient compassion is especially effective; it can record over the voice of conscience with an identical, mimicking voice, allowing us to commit feats of horror with placidity. The last bloody century provides any number of examples of the "banality of evil."

When we object to these bizarre new uses of technology, we tend reflexively to say that such undertakings constitute "playing God." We sense that God has something to do with this whole business of life and death, and that there are some ways we can assist his work, and some things we should respectfully back away from. We say we "feel" it, but the impulse comes from a different place than either emotion or rationality. We know it's not merely the voice of our pet notions and desires, because it has a propensity for telling us things we don't want to hear. It's more like a still, small voice inside.

Now more than ever, it is time to amplify that voice. As technology races into these realms of death-scented life, the leaps are greater and the decisions come faster. Everyone, not just ethicists, should become more intentional about listening to that quiet, yet authoritative, voice. Until we do, better lock up your monkeys.