People often claim that certain things are wrong or that certain actions should not be done because doing so would be “unnatural.” This argument is sometimes used in conjunction with the “playing God” argument, but it does not require a religious foundation.
Taken literally, the argument rests on three assumptions: there is a natural way things should be, we should act in accord with the natural way and unnatural things and actions are morally wrong. Defining what is natural and what is not is a critical part of this method. Fortunately, there are moral theories that are based on the concept of human nature or a natural way and they can be used by those employing this method. Aristotle, for example, bases his morality on his view about human nature. Taoism, although claiming to eschew ethics, includes a conception of nature and endorses acting in accord with this nature.
One common version of this method is based on the assumption that if X is not done in nature or does not exist in nature, then X is wrong. Interestingly, this method is often used in situations when it turns out that X actually happens in nature.
Taken metaphorically, this method is based on the assumption that people should not go beyond certain limits. What it means to make decisions or take actions beyond these limits must be defined. This is often defined in terms of arrogance or acting outside the limits of normal constraints. Obviously, why this should not be done must also be defended.
In many cases when people use this method they are making a tacit or hidden appeal to another moral theory. For example, doing something unnatural might be seen as having terrible consequences. In this case the argument would be an appeal to consequences based on a consequentialist approach.
While this method has dramatic appeal, it is usually better to use the underlying moral theory rather than playing the “unnatural card.”
This method has the following three steps:
Step 1: Argue that X or doing X is unnatural
Step 2: Argue that unnatural things or actions are wrong.
Step 3: Conclude that X is wrong or X should not be done.
This method is often employed to argue that homosexuality is immoral. Following this method, the first step would be to argue that homosexuality is an unnatural lifestyle. The second step would be to argue that people should not live unnatural lifestyles. The conclusion would be that homosexuality is morally wrong.
Like the “playing God” method, this method is often employed to argue against scientific “tampering.” For example, it might be used to argue against genetic engineering. The first step would be to argue that creating new life forms with genetic engineering creates unnatural things. The second step would be to argue that people should not create unnatural things. The conclusion would be that the use of genetic engineering to create new life forms is morally wrong.
Since this method rests on using unnaturalness as a moral defect, defining what is natural is critical. While people often uncritically make assumptions about what is natural and unnatural, presenting a coherent and plausible account of what is natural is rather difficult.
If natural is taken as being non-artificial, then all technology ranging from shoes to space shuttles would be immoral. This seems to be rather absurd.
If natural is taken in terms of the way things should be, the method seems to be circular since the argument would be that people should not do things they should not do.
Fortunately, as noted above, moral theorists have developed accounts of nature that can be employed (perhaps using an argument from authority) when using this method. In such uses, the applying moral theories method would be combined with this method to develop the argument.
As with the “playing God” argument, one way to respond (at least in a live conversation) is to require that the person spell out exactly how X is unnatural and why X is wrong. This is can also be a request for the person to explicitly state the underlying theory/principle they are actually employing. This is not a counter-argument but can be used to expose the lack of an argument on the other person’s part. If it can be shown that the person has not spelled out how X is unnatural and why this is wrong and conclude they did not make their case-they merely expressed their unsupported opinion.
A second way to reply is to show that it is acceptable to be “unnatural” in similar situations. This can be done by an argument by analogy. The analogy is drawn between the situation at hand and a similar situation in which making the decision or taking the action is acceptable. The challenge is finding an analogy that is acceptable.
Using the genetic engineering example, it can be pointed out that people have been altering animals through selective breeding for thousands of years without being accused of engaging in unnatural activities. Genetic engineering is simply a more efficient method of achieving the ends of selective breeding. Therefore, genetic engineering is not unnatural.
A third way to reply is by Showing that the act or thing occurs in nature. For example, some people contend that homosexuality is common among animals. So, it is not unnatural. Therefore it is not morally unacceptable. The Daily Show did a rather interesting segment on gay penguins that makes fun of the unnatural argument.