There is a scene in C.S. Lewis’s The Pilgrim’s Regress where the hero has been imprisoned by a giant called the Spirit of the Age, whose glance turns everything transparent so that one can “see through” it. The jailor who works for the giant furthers this process by debunking ‘social constructs’ with graphically brutal descriptions of the food he provides to the prisoners. One day he offers the prisoners milk while making a sneering comment about how they might as well be drinking the cow’s “other excretions.”
At this point the hero exclaims “Thank goodness! Now I know you don’t really believe what you’re saying!” and then proceeds to point out that there is an obvious, objective difference between milk, which is given to feed the young, and, say, urine, which isn’t. It’s not a question of convention or habit or mythology or belief; it’s a question of what in fact happens.
Our own zeitgeist hasn’t lost the taste for this particular game, which indeed is a very old one. It might be called the argument from ambiguity, and how it works is that, rather than trying to establish a given position, one instead claims that the relative concepts and categories cannot be clearly defined and thus cannot be objectively applied. This often manifests in terms like “shades of grey” or “who’s to say?” or “spectrums,” and it has a superficial credibility in that hard cases can be found in most subjects, and bringing these up can lend the speaker an air of intellectual sophistication.
Facts Don't Care About Your Ambiguity
But the argument almost always has the same weakness as it ever had, and which is illustrated in the scene from The Pilgrim’s Regress; namely, that its power comes from ignoring or suppressing some pertinent fact (e.g. that milk in fact feeds young, that a child has unique DNA upon conception, and so on). Typically it is used when the factual basis for a position is very weak, since it amounts to denying that the facts can be adequately known. It’s essentially the rhetorical version of mutual assured destruction: admitting that you can’t win, but trying to ensure the other side can’t either.
That isn’t to say that appeals to ambiguity are always illegitimate. There are cases where confusion and uncertainly truly does derail a given position. The issue of race would be a good example. While it’s true there are broad, obvious racial features (e.g. skin color), the actual make up of any given person’s ethnicity—that is, their actual genetic background—is a very ambiguous and uncertain thing indeed.
Because an individual’s heritage comprises not only his parents, but his parents’ parents, and their parents and so on back beyond the reach of human knowledge. Thus, there is no way, conceivably, to untangle the mixed bloodlines of any given individual to identify whether a given trait was due to one bloodline or another or to the blending of two or more.
Race, therefore, is inherently ambiguous, at least for scientific purposes, because the relevant factor—ancestry—is a continuous and convoluted blend of factors beyond our ability to untangle and study it. It is not possible to isolate given strands of inheritance, and even if we could, those strands themselves are blends of yet earlier strands. Therefore, anyone who wished to argue that a given race has certain traits and can be selectively bred to produce them would have his position discredited by the inherent ambiguity of the subject of race.
But note what we did there: when appealing to ambiguity, we were appealing to a clear fact about race, a fact that anyone can observe and recognize. Anyone who thinks about it can see that, say, a Chinese man today is likely to have genetic ancestors from all over eastern Asia to a greater or lesser extent, and that if a given ancestry produces one result, blending two different ancestries will produce something different than either. Ambiguity itself, when legitimate, is an objective fact about something that can be observed and independently verified
Sex Is Not A Spectrum
This is not the case for, say, sex. Many today will argue from ambiguity that the concept of ‘man’ and ‘woman’ cannot be clearly defined, and that it exists on a spectrum of values, emotions, and experiences, the same being true for ‘man.’ Sex and gender, in fact, are claimed as subjective, ambiguous ideas.
The chief problem with this view is that human beings exist.
What I mean is, every human being currently alive is alive because a man laid with a woman, either directly or indirectly (‘In-Vitro Fertilization’ and other scientific workarounds are fundamentally just a different way for a man’s seed to reach a woman’s body). Every person you meet or encounter was born of woman and begotten by man. Because there is no other way a human being can be created.
That’s not something socially constructed, or subject to interpretation or based on a belief system. That is what, in fact, happens.
So, in fact, ‘man’ and ‘woman’ have very clear definitions: a man is a human being capable of begetting children, a woman a human being capable of bearing them, and only the union of the two produces children. This is something anyone can verify for himself by observation. If you dispute this, you are disputing the meaning of words in the English language, and even if you won, you would still need words to account for which one bears and which one begets, mean you would have the words ‘man and woman’ shorn of any content, the equivalent of having a canceled deed to a house.
The standard answer to this is that the fact of sterility alters or discredits this position. But it doesn’t, because in such cases we can point to some objective fact, some flaw or damage to the system that prevents the normal process. That is, conception would have been possible but for such-and-such an issue. Whereas in any other case – of a man lying with a man, for instance – it is fundamentally impossible. Only the male can beget; only the female can bear. To make an analogy, a boat is a vessel for navigating on water. But some boats have holes in them and can’t float. That does not mean the capacity to float is irrelevant to the definition of a boat.
In the face of such facts, someone appealing to ambiguity will often ask, “why does it matter?” But the more pertinent question is, “why doesn’t it matter?” Why should an objective fact count for nothing? Besides which, if we can define a concept clearly, based on observable, objective facts, then that itself means the concept is not ambiguous.
The truth is that most of our concepts and categories are rooted in these kinds of facts. Aristotle pointed this out long ago; the idea of a horse is based on the common features that we observe in all horses. It is not arbitrary or ambiguous: these traits do, in fact, exist and anyone who likes can go and find them out.
Also note that this sort of thing is not a matter of science and therefore isn’t subject to scientific reversal. That is to say, science may discover a new planet, or discover that the planets do not, in fact, move in the way previously believed, or that what was thought to be a planet is in fact something else, but the definition of a planet versus, say, a moon is not something that can be ‘discredited’ by scientific research; that one orbits a star and another orbits a planet is simply what is meant by those terms. Appeals to science to maintain ambiguity, as in the case of, say, sex or the definition of life, are therefore irrelevant.
What all this amounts to is something very simple; that ambiguity, like everything else, stands and falls on evidence and reason. There are clear factors that make a concept ambiguous or not, and if one tries to argue from ambiguity, he had better be able to show that the subject under discussion is in fact ambiguous.