Some enhancement conservatives like Michael Sandel and Francis Fukuyama worry that if we allow unrestricted freedom to enhance human bodies, we may lose our humanity, and the meaning we find in our lives. For Fukuyama, for example, our finitude gives us meaning; for Sandel, it’s the sense that life is a gift, and not something we created.
But both accept therapeutic use of enhancement technologies. If a person were born with a genetic abnormality that caused very low IQ, for example, Fukuyama and Sandel would both accept that we should be allowed to use, say, a genetic enhancement technique to “correct” this, and give the person a normal IQ.
But who’s to say what’s normal and what’s low? In general, the conservative answer appeals to the average person, and what sorts of attributes such a person would have. The boundaries of disease, disability, and mildly lower levels of ability, are hard to map. But something can be labelled an “abnormality,” by some means, Sandel and Fukuyama accept that it can be treated.
This would rule out, for them, giving a person with an average (say, 90-110) IQ an enhancement to genius level. Probably Fukuyama and Sandel’s IQs are notably higher than the average level, but they don’t want the average person to be able to enhance to their level using an intervention like drugs, genetic engineering, or some kind of neural implant. Presumably, they’re OK with better schooling, being raised by educated parents, living in a house with books, and having parents who have time to give personal attention to children, all of which actually do account for a lot of IQ difference.
Now, suppose we find out that the “average” IQ is the result of a widespread mutation that occurred because, let’s say, the Black Plague injured the standard genome some 500 years ago. Most people have the damaged gene; some, like Sandel and Fukuyama, do not. Now it seems that most people are “abnormal,” at least if we sum across history. Now would it be ok to “cure” them of this bad mutation so they could have Sandel/Fukuyama-level IQ?
The point being: we have no reasonable historical baseline for what’s ‘normal’ in many traits. Even prior to the widespread use of steroids, athletic records were continually broken in the modern era; IQ has risen drastically in the last century (cf. “Flynn effect”); and life expectancy has nearly doubled in the last 200 years. While this latter is partly due to drastically decreased infant mortality, life expectancy at age sixty has more than doubled in the last 200 years, from 69 to 89 (i.e. from 9 to 19 years.) Perhaps enhancements are merely correcting for errors in our environment that have damaged our bodies; it’s not as though someone from 1800 couldn’t have lived to be 89; they probably just lacked our enhancements (better education, clean water, access to medical care, etc.)
Without knowing why something is “normal” or “average,” it seems unfair to declare that average to be a baseline, and any therapy that improves above this baseline to be an “enhancement.” It could simply be a correction, that is, a therapy.