Marvin Minsky

Did you know that one of the world’s foremost thinkers on the subject of artificial intelligence (AI) also invented the confocal microscope?

Mathematician by training, visionary thinker by nature, Marvin Minsky has made lasting contributions to disciplines as diverse as cognitive psychology, robotics, optics, and computational linguistics.

Currently professor of Media Arts and Sciences at MIT, Minsky wrote the seminal work Perceptrons, with colleague Seymour Papert, delineating the foundation for artificial neural networks.  His more recent book, The Emotion Machine, critiques popular theories on the function of the human mind.

But in 1955 Marvin Minsky had a problem.

His efforts to solve that problem led to a breakthrough in microscope technology and a leap forward in science.

Lenses, Prisms, Diaphragms

Minsky’s life-long love affair with machines began in childhood.  His father was an opthalmologist and the family home was full of lenses, prisms, diaphragms and other instruments.  Minsky would take each of them apart and his father would “quietly put them together again.” (Minsky, Scanning, 1988)

After completing his undergraduate studies at Harvard in 1950 and his PhD at Princeton in 1954, both in the field of mathematics, he was invited to become a Junior Fellow at Harvard.  While a student he had developed a fascination with the human brain and learning process, and devoured all the knowledge he could about the nervous system and how nerve cells are connected.

Now, as he began his work as a Junior Fellow, Minsky took stock of the available information on brain cells and came to a conclusion:  the technology of the day was insufficient to create a complete neural “wiring diagram” due to the issue of…

Scattered Light

In a memoir published in 1988, Minsky described the problem he was facing at the time:

“To be sure, a good deal was known about the shapes of certain types of nerve cells, because of the miraculous way in which the Golgi treatment tends to pick out a few neurons and then stain all the fibres that extend from them. But this permits you to visualize only one cell at a time, whereas to obtain the required wiring diagram you need to make visible all the cells in a three dimensional region. And here was a critical obstacle: the tissue of the central nervous system is solidly packed with interwoven parts of cells. Consequently, if you succeed in staining all of them, you simply can’t see anything. This is not merely a problem of opacity because, if you put enough light in, some will come out. The serious problem is scattering. Unless you can confine each view to a thin enough plane, nothing comes out but a meaningless blur. Too little signal compared to the noise: the problem kept frustrating me.” (Scanning, 1988)

Obsessed with the issue of scattered light, Marvin Minsky set up shop in a workroom at the Lyman laboratory of Physics at Harvard.  The result of his efforts was a single-point illumination system using a spatial pinhole to eliminate out-of-focus light.

In order for single-point illumination to work, specimens are scanned point by point.  This could be a slow process at the time, due to a lack of light sources that were bright enough.  Minsky originally used a carbon arc, which he then replaced with a zirconium arc.  It wasn’t until years later and the advent of laser technology, that confocal microscopy became a viable option for researchers.

Confocal microscope prototype

Another limitation to the original confocal microscope was the lack of computing power.  When Minsky developed his technology, computers were just becoming available.  His friend Russel Kirsch was running some of the first tests involving computer image analysis at the time, and invited him to experiment with the SEAC computer at the Bureau of Standards.

The SEAC computer was the first programmable computer in U.S. history, and had a whopping 6000 bytes of storage; unfortunately this wasn’t enough memory to process the images they were generating.  Minsky and Kirsch also suffered from a dearth of adequate devices for digitizing the image signals.

The Society of the Mind

Although most of his career has been spent as an AI thought leader and theorist, Marvin Minsky did make further contributions to the world of laboratory instruments and machines.

After inventing the confocal microscope, he pursued work on a mechanical microscope and micromanipulator, and later designed and built a sophisticated robotic arm.  He also built the first head-mounted graphical display, and SNARC, the first randomly wired neural networking machine.

He went on to develop the Society of the Mind theory in the early 1970s, offering the possibility that what we think of as intelligence might actually be the product of the interaction of non-intelligent parts.

“To me, we’re just big gadgets, and we’re made out of lots of little gadgets, and the important thing is to find out how to put them all together.”  (Minsky, Gadgetoff presentation, 2007)

Whether or not you share Marvin Minsky’s vision of man as machine, there’s no arguing with human ingenuity.  It’s amazing what we can accomplish when faced with a problem in search of a solution.


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