Uit: Language in Thought and Action, door S.I. Hayakawa.

Chapter 10 

On Definitions

Definitions, contrary to popular opinion, tell us nothing about things. They only describe people's linguistic habits; that is, they tell us what noises people make under what conditions. Definitions should be understood as statements about language.
 
     House. This word, at the next higher level of abstraction, can be substituted for the more cumbersome expression, "Something that has characteristics in common with Bill's bungalow, Jordan's cottage, Mrs. Smith's guest home, Dr. Jones's mansion. . . ."
   Red. A feature that rubies, roses, ripe tomatoes, robins' breasts, uncooked beef, and lipsticks have in common is abstracted, and this word expresses that abstraction.
   Kangaroo. Where the biologist would say "herbivorous mammal, a marsupial of the family Macropodidae," ordinary people say "kangaroo."


    Now it will be observed that while the definitions of "house" and "red" given here point down the abstraction ladder (see the charts) to lower levels of abstraction, the definition of "kangaroo" remains at the same level. That is to say, in the case of "house," we could if necessary go and look at Bill's bungalow, Jordan's cottage, Mrs. Smith's guest home, and Dr. Jones's mansion, and figure out for ourselves what features they seem to have in common; in this way, we might begin to understand under what conditions to use the word "house." But all we know about "kangaroo" from the above is that where some people say one thing, other people say another. That is; when we stay at the same level of abstraction in giving a definition, we do not give any information, unless, of course, the listener or reader is already sufficiently familiar with the defining words to work himself down the abstraction ladder. Dictionaries, in order to save space, have to assume in many cases such familiarity with the language on the part of the reader. But where the assumption is unwarranted, definitions at the same level of abstraction are worse than useless. Looking up "indifference" in some cheap pocket dictionaries, we find it defined as "apathy"; we look up "apathy" and find it defined as "indifference."
    Even more useless, however, are the definitions that go up the abstraction ladder to higher levels of abstraction-the kind most of us tend to make automatically. Try the following experiment on an unsuspecting friend:
 
  "What is meant by the word red?"
"It's a color."
"What's a color?"
"Why, it's a quality things have."
"What's a quality?"
"Say, what are you trying to do, anyway?"

You have pushed him into the clouds. He is lost.
    If, on the other hand, we habitually go down the abstraction ladder to lower levels of abstraction when we are asked the meaning of a word, we are less likely to get lost in verbal mazes; we will tend to "have our feet on the ground" and know what we are talking about. This habit displays itself in an answer such as this:
 
  "What is meant by the word red?"
"Well, the next time you see some cars stopped at an intersection, look at the traffic light facing them. Also, you might go to the fire department and see how their trucks are painted."


"Let's Define Our Terms"

An extremely widespread instance of an unrealistic (and ultimately superstitious) attitude toward definitions is found in the common academic prescription, "Let's define our terms so that we shall all know what we are talking about." As we have already seen in Chapter 4, the fact that a golfer, for example, cannot define golfing terms is no indication that he cannot understand and use them. Conversely, the fact that a man can define a large number of words is no guarantee that he knows what objects or operations they stand for in concrete situations. Having defined a word, people of ten believe that some kind of understanding has been established, ignoring the fact that the words in the definition of ten conceal even more serious confusions and ambiguities than the word defined. If we happen to discover this fact and try to remedy matters by defining the defining words, and then, finding ourselves still confused, we go on to define the words in the definitions of the defining words, and so on, we quickly find ourselves in a hopeless snarl. The only way to avoid this snarl is to keep definitions to a minimum and to point to extensional levels wherever necessary; in writing and speaking, this means giving specific examples of what we are talking about.

Operational Definitions

Another way to keep extensional levels in mind, when definitions are called for, is to use what physicist P. W. Bridgman called "operational definitions." As he says,
 
  To find the length of an object, we have to perform certain physical operations. The concept of length is therefore fixed when the operations by which length is measured are fixed. ... In general, we mean by any concept nothing more than a set of operations; the concept is synonymous with the corresponding set of operations.2

    The operational definition, then, as Anatol Rapoport explains, is one that tells you "what to do and what to observe in order to bring the thing defined or its effects within the range of one's experience." He gives the following simple example of how to define "weight": go to a railroad station or drugstore, look for a scale, stand on it, put in a penny, read the number at which the pointer comes to rest. That is your weight. But supposing different scales give different readings? Then your weight can be said to be within the range of, say, 140 to 145 pounds. With more accurate scales you might get closer readings, such as 142 pounds plus-or-minus one. But there is no "property" called weight that exists apart from the operations measuring it. As Rapoport says, "If the only way we can be aware of the amount of weight is by means of the scale, then the very definition of weight has to be in terms of the scale." 3
    Such, then, is the scientific, or "operational," point of view towards definition---one that attempts rigidly to exclude non-extensional, non-sense statements. We can extend this idea from science to the problems of everyday life and thought. Just as there is no such thing as "length" apart from the operations by which length is measured, just as there is no "weight" apart from the operations by which weight is determined, there is likewise no "democracy" apart from the sum-total of democratic practices, such as universal franchise, freedom of speech, equality before the law, and so on. Similarly, there is no such thing as "brotherhood" apart from brotherly behavior, nor "charity" apart from charitable actions.
    The operational point of view does much to keep our words meaningful. When people say things like, "Let's have no more of progressive methods in our schools," "Let's get back to sound business principles in running our county government," "Let's try to do the Christian thing," "Let's put father back as head of the family," we are entitled to ask, "what do you mean - extensionally speaking? To ask this question often - of ourselves as well as of others-is to do our bit towards reducing the vast amount of non-sense that is written, spoken, and shouted in this incredibly garrulous world.
    The best examples in everyday life of operational definitions are to be found in cookbooks, which describe the operations by means of which the entity defined may be extensionally experienced. Thus: "Steak Diane. Slice tenderloin beef very thin and give it a few whacks with a meat mallet to flatten it even more; sprinkle with salt and pepper to taste. Have your pan very hot. . . ." (The Sunset Cook Book.) Writers and speakers would do well to study cookbooks occasionally to increase the clarity and verifiability of their utterances.

2 The Logic of Modern Physics (1927), p. 5.


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