It’s summer. Perhaps things slow down for you and you’ve got a little more time to think expansively. I’m therefore allowing myself to try to convey one of the more complicated ideas that shapes our mind reading.

Two Kinds of Causality: Mechanical and Mental When explaining the behavior of anything or anyone, people use two distinct systems. One system focuses on matter, the other on mind. The one that focuses on matter is mechanical: matter in motion, thing A hits thing B. The cue ball hits the eight ball, thereby moving it. The one that focuses on mind is intentional: mind over matter, goal oriented. I intend to win this game of pool, so I intend to hit the eight ball into the corner pocket.

Mind has intention; matter does not. You have a mind, so you intend to do all sorts of things. In contrast, the Moon is all matter. It doesn’t intend to tug our oceans to make tides.

Mind Readers Dictionary: The Podfast : Play in Popup

Mind Readers Dictionary : Play in Popup

For all our brilliance, we humans still haven’t got a sound theory for explaining how mind and matter relate. It is one of science’s greatest remaining conundrums: How can a mind’s intentions do heavy lifting in the world of matter? An intention is such a wispy thing, as though it has no substance, no three-dimensionality. And yet an intention can move mountains. The Great Wall of China, Hoover Dam, the Pyramids—they started as people’s intentions.

You were once nothing more than a twinkle in your parents’ eyes. Now, look at you and the matter you move. And with a mind of your own, too! How did you get your minds’ intentions, anyway?

Two Kinds of Mental Causality: Intentions as Goals and Intentions as Mental Pictures Among those who wonder about such things, the word intention has come to convey two meanings. One is, of course, an intention to do things. The other is intention as opposed to extension. Intension is an internal representation (a picture in my mind’s eye) of what’s external to the mind. This second meaning of intention, as the mind’s-eye representation of an external thing, is where we get aboutness that was the topic of last week’s essay.

To use references to both kinds of intention in one sentence, I could say, “When I intend to win at pool, I somehow experience an intention of winning, a picture in my mind of the eight ball going into the corner pocket.”

From what we can tell, the Moon has neither of these two kinds of intentions. It neither intends to move the tides nor does it have an internal picture of moving the tides. If you doubt this, you are not alone. There’s the Man in the Moon, and there’s the eight ball’s intention to spite me by missing the corner pocket; intention comes so naturally to us humans that we can easily animate anything with it.

Integrating Mind and Matter, or if That’s too Hard, Getting Rid of Something Notice that the two kinds of intention each represent opposite one-way moves between the worlds of matter and mind. An intention to do something is mind acting on matter, the mental changing the physical. Conversely, intention as an internal representation of the outside world is matter acting on mind. In other words, it’s something in the outside world imposing an impression on us. The eight ball’s physical existence somehow configures my mind so that I end up picturing it.

We readily experience both kinds of intention, so maybe they just alternate. Something outside changes something inside us (by leaving an impression, a representation), which makes us intend to cause something outside. How they would alternate raises complex questions that some people find discouraging. They look for a simpler alternative that eliminates either one of the two kinds of intention, or one of the two kinds of causalities. This makes for four schools of thought:

Mind acts on matter only: There is both mind and matter, but mind governs matter. The mind shapes the matter in the world. As far back as Plotinus (204–270), we have had philosophers who argue for the primacy of the mind over matter, typically with God’s mind ultimately controlling all of matter. This approach poses awkward questions. For example, how does the mind—even God’s mind—get its ideas? Where do its ideas come from? This view remains popular, for example among New Agers who argue for the law of attraction: Whatever you think about you will magically bring to yourself. Your thoughts have direct power over the matter in the world.

Matter acts on mind only: There is both mind and matter, but matter governs mind. Your mind is wholly a product of your experiences of the physical world. Your mind is a collection of representations, but it doesn’t have any independent power to act on the world. The philosopher John Locke (1632–1704) leaned this way. Though he did believe the mind acted on the world, too, his emphasis was on how the mind is born blank and its content is wholly the product of experience. This view imposes an awkward question: If your mind is merely a collection of representations that can’t do anything, why even have it? Despite this problem, this is an extremely popular position in science and philosophy these days. Dan Dennett, America’s most popular living philosopher, argues it. So do many biologists: You, they say, are made of genes. Genes are merely a collection of impressions left by your ancestors’ environments over evolutionary history. You are merely a vehicle for the gene’s preservation and don’t have any powers of intention independent of them. But your genes don’t have any intention, either. They just happen to be a record of the past that happens to be instructions for making you. Weird. But popular!

Only mind: There is no physical reality. There is only the mental realm. You create your own reality by means of what you think. This position, called idealism, remains popular among anthropologists and philosophers, particularly in Europe.

Only matter: There is no mind, really. There’s only matter in motion. You are nothing more than a constellation of atoms, and the atoms determine all your behaviors. This theory, called elimitivism or computationalism, is very popular among cognitive scientists, researchers who treat the mind as though it were simply a fancy computer.

You may be surprised by these positions. In fact, I hope you are. Though counterintuitive approaches sometimes prove the most probable, these positions are both counterintuitive and improbable, raising more complications than they solve, which is why relating mind and matter remains an open question.

There is a new and improved explanation for the relationship between mind and matter, one that is both more intuitive and more scientifically credible. It, however, will have to wait for later essays.

Mind and Matter in Everyday Conversation Before ending this one, though, I’d like to identify a way these concepts apply to everyday life. Mind acting on matter is commonly called mind over matter. When we talk about mind over matter, we’re talking about free will—the courage to change things or, at the extreme, to change anything we put our minds to.

Conversely, matter over mind is the mind being determined by matter. When we talk about it, we’re talking about determinism, fate, or predestiny. If matter prevails over mind, you need the serenity to accept what you can’t change or, at the extreme, to accept that you can’t change anything.

In everyday conversation, we employ both mind causality and matter causality to explain each other’s behavior. When we’re frustrated with people’s stubbornness, we argue that they are cold, unfeeling, like robots or zombies—all matter, no mind, mindlessly committed to the wrong thing. We try to wake them up, to get them to think, to have a heart, to be more human, to wake their minds up. When we talk this way, it makes physical causality look bad and mental causality look good.

But sometimes we make physical causality look good and mental causality look bad. Think of the dedication of a soldier fighting the good fight, dedicated to one goal only: defending his people. He’s a virtuous machine. His determination and courage and nerves of steel make him a mechanism of merit. And then there’s the overly mental type: fickle, scheming, a second guesser, unreliable, someone who thinks too much for his or her or anyone’s good.

We reach for the mind and matter models of causality willy-nilly to suit our immediate conversational needs. Both the mind’s mental causality and matter’s mechanical causality can be held up as healthy or unhealthy. That science has yet to reach any kind of consensus on the relationship between mind and matter makes it easy to use the concepts loosely and strategically rather than accurately. Here, exaggerated for illustrative purposes, is an example of a spat in which mechanical and mental causality are invoked both as good things and bad things:

Jill: You’re not listening to a thing I’m saying. Here I am, trying to reason with you (mental—good). You’re like a robot homing device out for just one thing—satisfying your own desires (mechanical—bad).

Jack: No, I’m not. My mind is open. I’m just choosing not to go along with your selfishness, like anyone with a heart and mind would (mental—good). You’re the robot, mechanically insisting that I do your bidding. You’re like a juggernaut. You’re flying blind into a brick wall (mechanical—bad).

Jill: You’re right. I’m after only one thing, but you’re wrong about what it is. My sole purpose is to ensure our mutual happiness. And, really, it’s simple as one, two, three (mechanical—good). We could make each other happy if you would stop complicating it with all your mental activity (mental—bad). We simply need to act nice to each other (mechanical—good). We don’t need to work it out so much all the time (mental—bad).

In this example, what’s really determining whether Jack and Jill explain each other in terms of physical or mental causality? And what’s making them switch between treating each of these forms of causality as good or bad?

Really it’s their desires and preferences. We treat physical, mechanical determination as good if it causes people to do what we want them to do. We treat it as bad if it causes people to do what we don’t want them to do. Likewise, if mental causation gives people the courage to do what we want them to do, it’s good, and if it gives people the courage to do what we don’t want them to do, it’s bad.

And where do our desires and preferences come from? From our mind’s intentions. Or perhaps not. Maybe they’re physically, mechanically determined…