Alva Noë

Commercial brain training programs are taking another hit.

Humans and other primates see color thanks to three different kinds of cells in the retina.

By responding differently to short-, medium- and long-wavelength light, these cells provide the information the brain needs to figure out color in the environment.

This is how we do it. It's also how the birds and the bees do it.

But it turns out that our eyes do this imperfectly.

There's a provocative interview with the philosopher Daniel Dennett in Living on Earth.

The topic is Dennett's latest book — From Bacteria to Bach and Back: The Evolution of Minds — and his idea that Charles Darwin and Alan Turing can be credited, in a way, with the same discovery: that you don't need comprehension to achieve competence.

The Civic Museum of Natural History in Milan, which I visited last month, contains a magnificent collection of dioramas.

The museum was badly damaged during WWII, so the oldest of them dates back no earlier than the 1950s. But the diorama form is very much alive and well in this museum as, indeed, it is in some other natural history museums around the world. There are more than 100 dioramas in the Milan collection — and three new ones are coming soon.

Ask yourself: Where's your left hand?

I bet you don't need to look around to answer this. Or try this: Shut your eyes and reach down and touch your right heel. Not that hard for most of us.

Proprioception is the name of this ability we have that lets us keep track of, locate and make use of our own bodies. Proprioception works thanks to sensors in our muscles (muscle spindles), but it also depends on our sensitivity to stretching and pressure on the skin.

What happens if you lose proprioception?

The legendary Liverpool manager Bill Shankly said: "Football is not a matter of life and death. It's much more important than that."

Philosopher David Papineau quotes these words admiringly in his intelligent and very personal new book on sport titled Knowing the Score: What Sports Can Teach Us About Philosophy (And What Philosophy Can Teach Us About Sports).

The brain has evolved over evolutionary time scales of millions of years. So, what is the likelihood that the relatively recent advent of reading and writing, or motorized transport, or the Internet, could have changed our brains?

How do you know you are not now dreaming?

Any test you might perform, you might be merely dreaming that you are performing.

How can you get outside experience to verify that things are, at least once and for all, the way they seem to be?

This is philosophical skepticism in the potent and daring form that comes down to us from René Descartes.

Teachers and students alike have experienced the curious paradox that beginners, as a rule, tend to think too little about what they are doing because they think about what they are doing too much.

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