Impairment of parts and wholes

Aristotelians tend to find the following argument plausible:

1. Every disability includes the impairment of the proper function of one or more body parts or aspects.

2. If a part or aspect is impaired, the whole is impaired.

3. It is bad for one to be impaired.

4. Hence, every disability includes something that is bad for one.

The argument is compatible with a disability not being on balance bad for one (e.g., because maybe it is instrumentally good, for instance because it might contribute to personal growth in various ways, or make one a member of a particularly valuable community, etc.), but it implies that a disability is always bad for one in some respect. I don’t know that I have seen the argument expressly formulated as above, but I think something like this argument has always been at the back of my mind when thinking about disability.

There is philosophical literature challenging premise (3). But (3) is central to Aristotelian eudaimonism, so challenges to it did not seem very plausible to me.

However, it occurred to me yesterday that premise (2) may well be false. Think about cases of redundancy. Suppose toothies are a species of organisms that, unlike humans, have a variable number of teeth. The minimum number of teeth for the first-order proper functioning of a toothy is 60. With fewer teeth, a toothy can’t chew its food sufficiently well to function properly. However, typical healthy toothies exhibit significant redundancy in their dentation, and have anywhere between 70 and 100 teeth. Toothies that have from 60 and 69 teeth either do not have any redundancy in their dentation (at 60) or have insufficient redundancy (from 61 to 69). We can think of redundancy as a second-order proper function. Furthermore, toothies that have more than 100 teeth have the teeth crowded too much in the jaw, which isn’t good for them.

Toothies constantly grow need teeth and wear out old teeth. The worn-out teeth become flaky and weak, and eventually break and fall out. Now suppose that Alice is a toothy with 85 teeth, one of which is well on its way to wearing out. That tooth is impaired. However, Alice is not impaired by virtue of having an impaired tooth, because any number of teeth between 70 and 100 is sufficient for proper first-order (chewing) and second-order (redundancy) functioning of the organism. When that tooth falls out completely, Alice won’t be impaired, and when the teeth has partial function, as it does now, she isn’t impaired either. This, premise (2) is false.

We might suppose that even if Alice isn’t impaired by having an impaired tooth, she would be better off if that tooth weren’t impaired. But that need not be true. For it need not be true that having more teeth is better for one. Having more teeth makes for more redundancy but it also makes for more crowding in the jaw. When the tooth is wearing out, crowding may be decreased (the tooth may be thinner), even though redundancy is also decreased. So it need not be the case that the tooth impairment is in any way bad for Alice.

Now, it may seem that typical impairments of human bodies or aspects are unlike Alice’s tooth impairment. However, this is not clear. Consider intellectual aptitudes. These include reasoning aptitudes in the domains of the spiritual, moral, emotional, intuitive, interpersonal, spatial, logical, arithmetical, artistic, linguistic, kinaesthetic, etc., etc. But different humans have different social roles. Perhaps what is normal for humans is proper functioning of a sufficient number of these aptitudes, not of all of them, so that each human being can find a good niche in society. Furthermore, the sufficient number of these aptitudes may be one that is sufficient to ensure redundancy. In that case, if someone has more than enough redundancy, a severe impairment of one of the aptitudes need not imply a lack of proper function of the human as a whole. But we might, nonetheless, count someone with such a severe impairment of an intellectual aptitude as disabled. If so, being disabled in that respect need not imply being impaired on whole, or badly off in any respect.

However, in the intellectual aptitude case, shouldn’t we say that having more of the aptitudes is better? It isn’t like teeth, where having too many can be harmful, is it? Well, that isn’t completely clear. After all, it can be harder for a kid with many talents to specialize. But even if we grant that one is better off for having more of the aptitudes, this does not mean that lacking one or more is bad. It can be just less good. If Alice’s having 70 teeth is enough for her toothy nature, but 71 is better, then having only 70 isn’t bad, just less good.

That said, there are doubtless some parts or aspects of a human being such that proper function of the part or aspect is necessary for the proper function of the whole. The most obvious cases are the moral and spiritual: someone whose moral or spiritual aspects are impaired is indeed impaired as a person.

Acknowledgment: I feel that some of what I say is influenced in various ways by conversations I had with my superb student Hilary Yancey, but where I have failed to absorb her ideas at the time.