Wednesday, October 20, 2010

Is Vivisection Good Science?

Vivisection, originally defined as surgery conducted for experimental purposes on living organisms is now commonly used to describe any form of testing on live non-human animals. Anti-vivisection groups often criticize vivisection in the latter definition on the grounds that it is both cruel and a poor means of gathering knowledge that can be applied to our own species.

There is no question that a great deal of cruelty is involved in current vivisection practices, but is there any basis to the poor science accusation? The National Anti-Vivisection Alliance writes:

“The prime reason as to why animal testing cannot be applied to humans is due to the difference in species, genetic make-up and vary in physiology and biology. We simply cannot get the results from one species and apply it to another. Beagle dogs, for example, cannot get heart disease due to being designed for a high intake of meat in their diet due to being solely carnivores, yet heart disease is rife in the human population. Lemon juice, something used commonly, can kill cats as do grapes to dogs.”

The site is certainly correct that we would be ill advised to draw many conclusions about heart disease by studying another species that does not get it, but does this mean there is no knowledge to be garnered by using other species as models?

In the case of diet, other animals tend to make fairly poor models for humans since we have all evolved along different evolutionary paths to fill differing dietary niches. For many other things we might study this is not the case. Many other animals break down alcohol very similarly to the way we do. Why should we not be able to model the breakdown of alcohol in these animals? Many other animals have skin that bruises or burns and bones that break under similar conditions to our own. Why should we not be able to model the effects of trauma and injury on humans in these animals? Many other animals possess a very similar structure in their brains as we possess in the core region of our own. Why should we not be able to learn something about a drug's effect on the core of our brain by studying its effect in these other animals.

The American Anti-Vivisection Society claims, “Nine out of ten drugs that appear promising in animal studies go on to fail in human clinical trials,” as a reason why vivisection cannot be useful. Yet if we look back at the example of using other animals' brains as models for the core of our brain, it will certainly be necessary after this trial to ensure that a drug has no effect on other systems of our brain and that it doesn't have negative consequences on other areas of our body. We haven't learned this from the animal tests, but we still may have gathered valuable information about the way a drug operates in the area of our primary concern.

While many of the experiments currently being conducted we might not see as having any practical and applicable purpose, Carl Sagan makes the point incredibly clear in The Demon Haunted World why we must be careful when criticizing any striving for new knowledge as being without practical value:

Giving money to someone like Maxwell might have seemed like the most absurd encouragement of mere “curiosity-driven” science, and an imprudent judgment for practical legislators. Why grant money now, so nerdish scientists talking incomprehensible gibberish can indulge their hobbies, when there are urgent unmet national needs? From this point of view it's easy to understand the contention that science is just another lobby, another pressure group anxious to keep the grant money rolling in so the scientists don't ever have to do a hard day's work or meet a payroll.

Maxwell wasn't thinking of radio, radar, and television when he first scratched out the fundamental equations of electromagnetism; Newton wasn't dreaming of space flight or communication satellites when he first understood the motion of the moon; Roentgen wasn't contemplating medical diagnosis when he investigated a penetrating radiation so mysterious he called it “X-rays”; Curie wasn't thinking of cancer therapy when she painstakingly extracted minute amounts of radium from tons of pitchblende; Rowland and Molina weren't planning to implicate CFCs in ozone depletion when they began studying the role of halogens in stratospheric photochemistry.

Members of congress and other political leaders have from time to time found it irresistible to poke fun at seemingly obscure scientific research proposals that the government is asked to fund. Even as bright a senator as William Proxmire, a Harvard graduate, was given to making episodic “Golden Fleece” awards – many commemorating ostensibly useless scientific projects – including SETI. I imagine the same spirit in previous governments – a Mr. Fleming wishes to study bugs in smelly cheese; a Polish woman wishes to sift through tons of Central African ore to find minute quantities of a substance she says will glow in the dark; a Mr. Kepler wishes to hear the songs the planets sing.

We do not know the results that may come from our curious seeking of new knowledge. That said, this doesn't give researchers a blank check to use anyone or anything however they should please. Just imagine how much more we could learn with unrestricted testing on other humans! All the shortcomings and difficulties of tests in other species would be eliminated, yet for some reason modern society has nearly universally condemned the non-consensual medical experiments of Nazi Germany. Many of the animals we currently experiment on suffer much as we would in these experiments. We may require anesthesia, but by no means would we find this small token acceptable as we brutally violated humans in the same ways we do to other animals today. From an ethical perspective, our reckless testing on non-human animals is behind only our consumption of them for the greatest misdeeds of our day in terms of suffering caused.

The guidelines we place on animal testing ought to change to more resemble the ones we currently have in place protecting our fellow humans, but what effect would this have on science?

Prior to sending the first human into space, the United States had launched five different monkeys and a mouse into space between five individual missions. At the time we had little idea what effect the lack of gravity and radiation at high altitude might have on any travellers. Since these animals had all evolved with a similar dependence on gravity and ordinary radiation levels as we had, and we saw no evidence of systems in humans that should be uniquely sensitive to these conditions, these other animals made good sense as models for what might happen to a human in space. We found from these missions that the animals did survive and were able to continue to function in space with no obvious health consequences. What would the United States have done had we not been able to test on these animals? I suspect our first mission would have been to build an airplane similar to the current “Zero G” plane capable of flying in parabolic arcs for up to 30 seconds at a time simulating the weightlessness of space. Next we would have probably designed a mission to launch someone to an altitude where they could experience free fall for roughly 10 or 15 minutes. Finally once all of these had proved to be safe we would attempt a full earth orbit mission.

This would have required additional time and cost for all of the safety precautions we expect in human missions, but by no means would it have prohibited the space race. There may be other experiments that may not be as easy to replace, but we must also be careful not to underestimate our own combined ingenuity when presented with new problems to solve. A good ethical system should be able to weigh the potential harm caused to the subjects against the potential benefit for results. Today our system only begins to do that with human subjects, and comes nowhere close with non-human animals.

No comments:

Post a Comment