The Nominal Fallacy

The nominal fallacy is the error of believing that the label carries explanatory information.

An instance of the nominal fallacy is most easily seen when the meaning or importance of a term or concept shrinks with knowledge. One example of this would be the word “instinct.” “Instinct” refers to a set of behaviors whose actual cause we don’t know, or simply don’t understand or have access to, and therefore we call them instinctual, inborn, innate. Often this is the end of the exploration of these behaviors. They are the “nature” part of the nature-nurture argument (a term itself likely a product of the nominal fallacy) and therefore can’t be broken down or reduced any further. But experience has shown that this is rarely the truth.

One of the great examples: It was for quite some time thought that when chickens hatched and immediately began pecking the ground for food, this behavior must have been instinctive. In the 1920s, a Chinese researcher named Zing-Yang Kuo made a remarkable set of observations on the developing chick egg that overturned this idea—and many similar ones. Using a technique of elegant simplicity, he found that rubbing heated Vaseline on a chicken egg caused it to become transparent enough so that he could see the embryo inside without disturbing it. In this way, he was able to make detailed observations of the chick’s development, from fertilization to hatching. One of his observations was that in order for the growing embryo to fit properly in the egg, the neck is bent over the chest in such a way that the head rests on the chest just where the developing heart is encased. As the heart begins beating, the head of the chicken is moved up and down in a manner that precisely mimics the movement that will be used later for pecking the ground. Thus the “innate” pecking behavior that the chicken appears to know miraculously upon birth has, in fact, been practiced for more than a week within the egg.

Stuart Firestein explains why naming is not explaining.