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No. 2778:

Today, there's something about Mary. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Our bodies are a lot like machines. Some people go so far as to say they're nothing butmachines. Our bodies may be more complicated than a toaster oven, they argue, but we're built of the same atoms and subject to the same physical laws. Their logic is clear. However, as we know from experience, the human body has at least one big difference from machines: it can experience a craving for chocolate or the longing for companionship. Philosophers call these internal mental states qualia, and qualia are a constant source of debate.

In 1982 philosopher Frank Jackson proposed a thought experiment that led to a lively exchange. Imagine a brilliant scientist whom we'll call Mary locked in a room where everything she can see is black and white. (Bear in mind this is just a thought experiment.) From within her room, on her black and white computer, Mary studies the neurophysiology of vision. She understands, for example, that the color "red" is a certain wavelength of light, that when light of a particular wavelength strikes someone's retina it sends signals to the brain, and so on. She becomes an expert, learning all the physical facts there are about vision.

Mary from philosopher Frank Jackson's thought experiment

Now imagine Mary is released from her black and white room. She steps outside and for the first time sees red and blue and green and all the other colors. In a word, her reaction is likely to be "wow." And we ask, could a machine ever have a similar "wow" moment?

But philosopher Jackson was looking to make a much bigger point. He wonders if by experiencing colors, does Mary actually learn something new? Something she didn't grasp before leaving the room? If so, Jackson argues, it was something she wasn't able to learn just by studying the physical world. Ergo, not everything that can be known can be learned by studying the physical world.

Jackson's tight little argument caused quite a stir. It flew in the face of a widely held belief by many philosophers that any knowledge, including knowledge about the human mind, can be "brought back to ... statements ... [about] physical objects." In 2004, a collection of essays on Jackson's argument was published under the title, "There's Something About Mary." It contained scholarly rebuttals and analyses by many leading philosophers.

But the central issue — the existence of qualia — still remains foremost in modern discussions of mind. Our bodies are a lot like machines. But they go much further, converting what we see, hear, taste, touch, and smell into a marvelously textured experience; an experience defined by our very own, personal qualia. And that's a fact you needn't be a philosopher to appreciate.

A smiling child in a field of flowers

I'm Andy Boyd at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Notes and References:

For a related episode, see CONSCIOUSNESS.

F. Jackson. 1982. "Epiphenomenal Qualia." Philosophical Quarterly, 32, pp. 127-136.

Physicalism. From the Wikipedia website: Accessed March 6, 2012.

Qualia. From the Stanford Encyclopedia of Philosophy website: Accessed March 6, 2012.

There's Something About Mary. P. Ludlow, Y. Nagasawa, and D. Stoljar, eds. Cambridge, Massachusetts: MIT Press, 2004.

The picture of a young Marie Curie is in the public domain as its copyright has expired. The pictures of the strawberries and the smiling boy are from Wikimedia Commons.

This episode was first aired on March 8, 2012