As weblogger Rand Simberg recently noted, the arguments against cloning are missing in action.

Oh, there are plenty of people who oppose cloning. They just have trouble coming up with reasons that go beyond "I just don't like it."

That doesn't make for much of a discussion. It's hard to refute arguments against cloning that aren't made, but most "arguments" in the cloning debate are really just conclusions. For example, you can read Leon Kass and Daniel Callahan's recent piece in The New Republic from one end to another without getting a morally coherent argument as to why cloning is bad. (Note to Kass: "Slippery Slope" arguments are well and good, but you must still establish that the bottom of the slope is a bad place.)

Still, there are some common themes among cloning opponents that are worth unpacking here:

1. Cloning doesn't work well enough. It's too dangerous and is likely to produce deformed babies. Deliberately producing a child that will suffer serious genetic problems is unspeakable.

This is the best argument. But it's not an argument against cloning, just an argument against cloning with poor technology. If cloning worked perfectly every time, this argument wouldn't hold at all. Secondly, we don't consider it "unspeakable" for people who are at risk of spreading hereditary disease to have children — in fact, the Catholic Church, a major opponent of cloning, does not endorse birth control in order to prevent such an event. Nor are there laws against such couples having children. If there were, people would consider those laws to be "eugenics" laws, which are bad.

2. Cloning will work too well. It will produce so many successful clones that it will replace sexual reproduction, leading to a loss of genetic diversity.

The inconsistency with the argument above is obvious. Also, widespread cloning won't lead to a loss of diversity: at least, if everyone alive cloned him or herself once, we'd have exactly as much diversity as we have now. I suppose if someone produced six billion copies of Bill Gates we'd have a problem. But, really, how likely is that?

3. Cloning will produce soulless zombie tools of the corporate power structure.

No, it won't. Lucas aside, clones won't be any more soulless than identical twins, who are simply natural clones. And they won't be zombies unless something else is done to make them that way — like, perhaps, making them sit through The Phantom Menace a few hundred times. And that would be the crime against humanity, not the cloning that preceded it.

4. Cloning is "playing God."

What's that? Heart transplants were once "playing God." Now they're medicine. Ditto with in-vitro fertilization and, long ago, vaccination. "Playing God" is a synonym for "gives me the willies." (see below).

5. Cloning is against God's will.

No, it isn't. So there. Seriously, this isn't really an argument, but an attempt to shut down argument. It's also dubious theology. Given Adam's creation by God "in his own image," followed by Eve's creation by modification of a bit of Adam, and the command to go forth and multiply, it's as arguable that God likes cloning (and related biotechnology) as that God is against it. And that's if you care what Yahweh thinks. Lots of people, of course, don't. Some religious groups actually favor cloning.

6. Clones are unnatural.

Tell it to an identical twin. Besides, smallpox is natural; smallpox vaccine is not. Why are "natural" things necessarily good?

7. Cloning gives me the willies.

This is, I think, the core argument. Leon Kass thinks that the "revulsion" that we feel — or at any rate, that he feels — is a meaningful ethical guide. But many people felt revulsion, no less sincerely, at the thought of eating with black people, or of homosexuals, or of Jews. And, of course, many of us have a different intuition than Kass, feeling no revulsion at all. Why are the gut feelings of Kass, a man who says we already live lives that are too long and too healthy, privileged?

There may be a persuasive and well-founded case against cloning, but it hasn't been made yet in the public sphere. And the prevalence of sloganeering and "mad scientist" references makes me doubt that cloning opponents have much more than you see above. That's too bad, since we're supposed to be having a national debate on the subject. But debates require arguments, not just positions.

Glenn Harlan Reynolds is a law professor at the University of Tennessee and publishes InstaPundit.Com.  He is co-author, with Peter W. Morgan, of  The Appearance of Impropriety: How the Ethics Wars Have Undermined American Government, Business, and Society (The Free Press, 1997).

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