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The Society of Mind
What is interesting here is that Minsky, after being so keen on the neural network approach, now seemed disillusioned with it.
Together with Papert he worked on a new theory “The Society of Mind”, a strange, almost mystical, theory that was explained in a book of the same name. The book, consisting of 270 interconnected one-page ideas, is certainly fun to read as the following excerpt demonstrates:
Holist: I'll prove no box can hold a mouse. A box is made by nailing six boards together. But it's obvious that no box can hold a mouse unless it has some "mouse-tightness" or "containment". Now, no single board contains any containment, since the mouse can just walk away from it. And if there is no containment in one board, there can't be any in six boards. So the box can have no mouse-tightness at all. Theoretically, then, the mouse can escape!
Citizen: Amazing. Then what does keep a mouse in a box?
Holist: Oh, simple. Even though it has no real mouse-tightness, a good box can "simulate" it so well that the mouse is fooled and can't figure out how to escape.
Logo and tutle graphics
At the same time he diversified into the psychology of education. “The Society of Mind” was based on information and theories of child development and this suggested ways to improve the early environment. Minsky and Papert invented the programming language, Logo, and Minsky built the first Logo Turtle.
Logo is derived from the AI language Lisp and the Turtle is based on the ideas of turtle geometry. Commands such as forward, turn right and so on can be used to make the Turtle draw geometric patterns. This approach allowed very young children to learn to program and develop concepts that involved projecting their own frame of reference onto the Turtle. In the long run, however, Logo has to be seen as something of an error – it is about as unsuitable as a first computer language as you can imagine. Turtles turned out to be more useful and enduring.
Despite having put a damper on the development of neural networks Minsky has continued to develop impressive robots and vision systems at MIT. In 1969 he built the first “human-like” robot hand manipulator, complete with tactile sensor. He thought up the idea for the “binary tree” robot manipulator – a many-armed robot in the form of a binary tree that to the casual observer seems far more difficult to program than a simple robot arm.
An early Minsky robot piling bricks.
He has also had a long standing interest in music and why it exerts such a powerful influence over us. In 1970 he invented a musical variations synthesiser which composed music. His interests range into art, writing, dance and he is currently Toshiba Professor of Media Arts and Sciences as well as Computer Science.
In years to come Minsky will probably be remembered as the man who proved that perceptrons couldn’t learn, which is a shame given his other accomplishments. Every AI expert falls into the trap of thinking that real AI should be achievable within a few years and they always end up disillusioned when they discover that this isn’t possible. It isn’t because they over rate the power of the computer, it’s because they under rate the power and complexity of the human brain. The discovery that it’s more difficult isn’t the same as that it’s impossible.
The final question every wants to know the answer to is – was Marvin the Paranoid Android in “The Hitch Hiker’s Guide to the Galaxy” an offhand tribute to Minsky who built so many robots? A nice idea but according to the author the robot wasn't even his invention and was originally called "Marshall".