The Metaphorical Mind (excerpt)

 We are almost ready to dissolve Wallace's paradox that a forager's mind is capable of calculus. The human mind, we see, is not equipped with an evolutionarily frivolous faculty for doing Western science, mathematics, chess, or other diversions. It is equipped with faculties to master the local environment and outwit its denizens. People form concepts that find the clumps in the correlational texture of the world. They have several ways of knowing, or intuitive theories, adapted to the major kinds of entities in human experience: objects, animate things, natural kinds, artifacts, minds, and the social bonds and forces we will explore in the next two chapters. They wield inferential tools like the elements of logic, arithmetic, and probability. What we now want to know is where these faculties came from and how they can be applied to modern intellectual challenges.

Here is an idea, inspired by a discovery in linguistics. Ray Jackendoff points to sentences like the following:

    The messenger went from Paris to Istanbul.
    The inheritance finally went to Fred.
    The light went from green to red.
    The meeting went from 3:00 to 4:00.

The first sentence is straightforward: someone moves from place to place. But in the others, things stay put. Fred could have become a millionaire when the will was read even if no cash changed hands but a bank account was signed over. Traffic signals are set in pavement and don't travel, and meetings aren't even things that could travel. We are using space and motion as a metaphor for more abstract ideas. In the Fred sentence, possessions are objects, owners are places, and giving is moving. For the traffic light, a changeable thing is the object, its states (red and green) are places, and changing is moving. For the meeting, time is a line, the present is a moving point, events are journeys, beginnings and ends are origins and destinations. 

The spatial metaphor is found not only in talk about changes but in talk about unchanging states. Belonging, being, and scheduling are construed as if they were landmarks situated at a place:

    The messenger is in Istanbul.
    The money is Fred's.
    The light is red.
    The meeting is at 3:00.

The metaphor also works in sentences about causing something to remain in a state:

    The gang kept the messenger in Istanbul.
    Fred kept the money.
    The cop kept the light red.
    Emilio kept the meeting on Monday.

Why do we make these analogies? It is not just to co-opt words but to co-opt their inferential machinery. Some deductions that apply to motion and space also apply nicely to possession, circumstances, and time. That allows the deductive machinery for space to be borrowed for reasoning about other subjects. For example, if we know that X went to Y, we can infer that X was not at Y beforehand but is there now. By analogy, if we know that a possession goes to a person, we can infer that the person did not own the possession beforehand but owns it now. The analogy is close, though it is never exact: as a messenger travels he occupies a series of locations between Paris and Istanbul, but as Fred inherits the money it does not gradually come into his possession to varying degrees as the will is being read; the transfer is instantaneous. So the concept of location must not be allowed to merge with the concepts of possession, circumstance, and time, but it can lend them some of its inferential rules. This sharing is what makes the analogies between location and other concepts good for something, and not just resemblances that catch our eye.

The mind couches abstract concepts in concrete terms. It is not only words that are borrowed for metaphors, but entire grammatical constructions. The double-object construction—Minnie sent Mary the marbles—is dedicated to sentences about giving. But the construction can be co-opted for talking about communication:

    Minnie told Mary a story.
    Alex asked Annie a question.
    Carol wrote Connie a letter.

Ideas are gifts, communication is giving, the speaker is the sender, the audience is the recipient, knowing is having. 

Location in space is one of the two fundamental metaphors in language, used for thousands of meanings. The other is force, agency, and causation. Leonard Talmy points out that in each of the following pairs, the two sentences refer to the same event, but the events feel different to us:

    The ball was rolling along the grass.
    The ball kept on rolling along the grass.

    John doesn't go out of the house.
    John can't go out of the house.

    Larry didn't close the door.
    Larry refrained from closing the door.

    Shirley is polite to him.
    Shirley is civil to him.

    Margie's got to go to the park.
    Margie gets to go to the park.

The difference is that the second sentence makes us think of an agent exerting force to overcome resistance or overpower some other force. With the second ball-in-the-grass sentence, the force is literally a physical force. But with John, the force is a desire: a desire to go out which has been restrained. Similarly, the second Larry seems to house one psychic force impelling him to close the door and another that overpowers it. For Shirley, those psychodynamics are conveyed by the mere choice of the adjective civil. In the first Margie sentence, she is impelled to the park by an external force in spite of an internal resistance. In the second, she is propelled by an internal force that overcomes an external resistance.

The metaphor of force and resistance is even more explicit in this family of sentences:

    Fran forced the door to open.
    Fran forced Sally to go.
    Fran forced herself to go.

The very same word, force, is being used literally and metaphorically, with a common thread of meaning that we easily appreciate. Sentences about motion and sentences about desire both allude to a billiard-ball dynamics in which an agonist has an intrinsic tendency to motion or rest, and is opposed by a weaker or stronger antagonist, causing one or both to stop or proceed. It is the impetus theory I discussed earlier in the chapter, the core of people's intuitive theory of physics. 

Space and force pervade language. Many cognitive scientists (including me) have concluded from their research on language that a handful of concepts about places, paths, motions, agency, and causation underlie the literal or figurative meanings of tens of thousands of words and constructions, not only in English but in every other language that has been studied. The thought underlying the sentence Minnie gave the house to Mary would be something like "Minnie cause [house go-possessionally from Minnie to Mary]." These concepts and relations appear to be the vocabulary and syntax of mentalese, the language of thought. Because the language of thought is combinatorial, these elementary concepts maybe combined into more and more complex ideas. The discovery of portions of the vocabulary and syntax of mentalese is a vindication of Leibniz' "remarkable thought": "that a kind of alphabet of human thoughts can be worked out and that everything can be discovered and judged by comparison of the letters of this alphabet and an analysis of the words made from them." And the discovery that the elements of mentalese are based on places and projectiles has implications for both where the language of thought came from and how we put it to use in modern times.

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Other primates may not think about stories, inheritances, meetings, and traffic lights, but they do think about rocks, sticks, and burrows. Evolutionary change often works by copying body parts and tinkering with the copy. For example, insects' mouth parts are modified legs. A similar process may have given us our language of thought. Suppose ancestral circuits for reasoning about space and force were copied, the copy's connections to the eyes and muscles were severed, and references to the physical world were bleached out. The circuits could serve as a scaffolding whose slots are filled with symbols for more abstract concerns like states, possessions, ideas, and desires. The circuits would retain their computational abilities, continuing to reckon about entities being in one state at a time, shifting from state to state, and overcoming entities with opposite valence. W h e n the new, abstract domain has a logical structure that mirrors objects in motion—a traffic light has one color at a time but flips between them; contested social interactions are determined by the stronger of two wills—the old circuits can do useful inferential work. They divulge their ancestry as space- and force-simulators by the metaphors they invite, a kind of vestigial cognitive organ.

Are there any reasons to believe that this is how our language of thought evolved? A few. Chimpanzees, and presumably their common ancestor with our species, are curious manipulators of objects. W h e n they are trained to use symbols or gestures, they can make them stand for the event of going to a place or putting an object in a location. The psychologist David Premack has shown that chimpanzees can isolate causes. Given a pair of before-and-after pictures, like an apple and a pair of apple halves or a scribbled sheet of paper next to a clean one, they pick out the object that wreaked the change, a knife in the first case and an eraser in the second. So not only do chimpanzees maneuver in the physical world, but they have freestanding thoughts about it. Perhaps the circuitry behind those thoughts was co-opted in our lineage for more abstract kinds of causation.

How do we know that the minds of living human beings really appreciate the parallels between, say, social and physical pressure, or between space and time? How do we know that people aren't just using dead metaphors uncomprehendingly as when we talk of breakfast without thinking of it as breaking a fast? For one thing, space and force metaphors have been reinvented time and again, in dozens of language families across the globe. Even more suggestive evidence comes from my own main field of research, child language acquisition. The psychologist Melissa Bowerman discovered that preschool children spontaneously coin their own metaphors in which space and motion symbolize possession, circumstance, time, and causation:

    You put me just bread and butter.
    Mother takes ball away from boy and puts it to girl.
    I'm taking these cracks bigger [while shelling a peanut].
    I putted part of the sleeve blue so I crossed it out with red [while coloring]
    Can I have any reading behind the dinner?
    Today we'll be packing because tomorrow there won't be enough space to pack.
    Friday is covering Saturday and Sunday so I can't have Saturday and
    Sunday if I don't go through Friday.
    My dolly is scrunched from someone . . . but not from me.
    They had to stop from a red light.

The children could not have inherited the metaphors from earlier speakers; the equation of space with abstract ideas has come naturally to them.

Space and force are so basic to language that they are hardly metaphors at all, at least not in the sense of the literary devices used in poetry and prose. There is no way to talk about possession, circumstance, and time in ordinary conversation without using words like going, keeping, and being at. And the words don't trigger the sense of incongruity that drives a genuine literary metaphor. We all know when we are faced with a figure of speech. As Jackendoff points out, it's natural to say, "Of course, the world isn't really a stage, but if it were, you might say that infancy is the first act." But it would be bizarre to say, "Of course, meetings aren't really points in motion, but if they were, you might say that this one went from 3:00 to 4:00." Models of space and force don't act like figures of speech intended to convey new insights; they seem closer to the medium of thought itself. I suspect that parts of our mental equipment for time, animate beings, minds, and social relations were copied and modified in the course of our evolution from the module for intuitive physics that we partly share with chimpanzees.

Metaphors can be built out of metaphors, and we continue to borrow from concrete thoughts when we stretch our ideas and words to encompass new domains. Somewhere between the basic constructions for space and time in English and the glories of Shakespeare there is a vast inventory of everyday metaphors that express the bulk of our experience. George Lakoff and the linguist Mark Johnson have assembled a list of the "metaphors we live by"—mental equations that embrace dozens of expressions:

    ARGUMENT IS WAR:
    Your claims are indefensible.
    He attacked every weak point in my argument.
    Her criticisms were right on target.
    I've never won an argument with him.

    VIRTUE IS UP:
    He is high-minded.
    She is an upstanding citizen.
    That was a low trick.
    Don't be underhanded.
    I wouldn't stoop to that; it is beneath me.

    LOVE IS A PATIENT:
    This is a sick relationship.
    They have a healthy marriage.
    This marriage is dead—it can't be revived.
    It's a tired affair.

    IDEAS ARE FOOD:
    What he said left a had taste in my mouth.
    All this paper has are half-baked ideas and warmed-over theories.
    I can't swallow that claim.
    That's food for thought.

Once you begin to notice this pedestrian poetry, you find it everywhere. Ideas are not only food but buildings, people, plants, products, commodities, money, tools, and fashions. Love is a force, madness, magic, and war. The visual field is a container, self-esteem is a brittle object, time is money, life is a game of chance.

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The ubiquity of metaphor brings us closer to a resolution to Wallace's paradox. The answer to the question "Why is the human mind adapted to think about arbitrary abstract entities?" is that it really isn't. Unlike computers and the rules of mathematical logic, we don't think in Fs and x's and y's. We have inherited a pad of forms that capture the key features of encounters among objects and forces, and the features of other consequential themes of the human condition such as fighting, food, and health. By erasing the contents and filling in the blanks with new symbols, we can adapt our inherited forms to more abstruse domains. Some of these revisions may have taken place in our evolution, giving us basic mental categories like ownership, time, and will out of forms originally designed for intuitive physics. Other revisions take place as we live our lives and grapple with new realms of knowledge.

Even the most recondite scientific reasoning is an assembly of downhome mental metaphors. We pry our faculties loose from the domains they were designed to work in, and use their machinery to make sense of new domains that abstractly resemble the old ones. The metaphors we think in are lifted not only from basic scenarios like moving and bumping but from entire ways of knowing. To do academic biology, we take our way of understanding artifacts and apply it to organisms. To do chemistry, we treat the essence of a natural kind as a collection of tiny, bouncy, sticky objects. To do psychology, we treat the mind as a natural kind. 

Mathematical reasoning both takes from and gives to the other parts of the mind. Thanks to graphs, we primates grasp mathematics with our eyes and our mind's eye. Functions are shapes (linear, flat, steep, crossing, smooth), and operating is doodling in mental imagery (rotating, extrapolating, filling, tracing). In return, mathematical thinking offers new ways to understand the world. Galileo wrote that "the book of nature is written in the language of mathematics; without its help it is impossible to comprehend a single word of it."

Galileo's dictum applies not only to equation-filled blackboards in the physics department but to elementary truths we take for granted. The psychologists Carol Smith and Susan Carey have found that children have odd beliefs about matter. Children know that a heap of rice weighs something but claim that a grain of rice weighs nothing. When asked to imagine cutting a piece of steel in half repeatedly, they say that one will finally arrive at a piece so small that it no longer takes up space or has any steel inside it. They are not of unsound mind. Every physical event has a threshold below which no person or device can detect it. Repeated division of an object results in objects too small to detect; a collection of objects each of which falls below the threshold may be detectable en masse. Smith and Carey note that we find children's beliefs silly because we can construe matter using our concept of number. Only in the realm
of mathematics does repeated division of a positive quantity always yield a positive quantity, and repeated addition of zero always yields zero. Our understanding of the physical world is more sophisticated than children's because we have merged our intuitions about objects with our intuitions about number.

So vision was co-opted for mathematical thinking, which helps us see the world. Educated understanding is an enormous contraption of parts within parts. Each part is built out of basic mental models or ways of knowing that are copied, bleached of their original content, connected to other models, and packaged into larger parts, which can be packaged into still larger parts without limit. Because human thoughts are combinatorial (simple parts combine) and recursive (parts can be embedded within parts), breathtaking expanses of knowledge can be explored with a finite inventory of mental tools.

 

  -Steven Pinker, How the Mind Works, ch 5 pg 352