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Biological plausability for the Society of Mind theory


A theory of why evolution is a slow process
Marvin Minsky Scientist
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I think early 1940s a Japanese scientist named Susumu Ohno wrote a book called Evolution by Gene Duplication. And his central idea was that you don’t improve things by making small changes exactly. You don’t modify genes so often as you make new ones by copying old ones. Or in fact, I think major improvements or advances in biological species might be by having an entire extra chromosome, a copy of an old chromosome. Each human has 23 pairs of chromosomes. And, I think chimpanzees have 22 or there's... there was some accident in which one of the chromosomes broke up and duplicated and divided and went on a different course of evolution. That’s a bad example. But anyway, what’s the point? The point is that if you evolve by making changes in genes, then for each advance you’re going to also have a step backwards. Let’s take a nice example. Imagine that there’s a certain gene which is expressed both in making your human brain and your human heart. There are lots of genes that are active in... in many different organs. Well now, suppose you make a little change in this gene that makes the heart a little better at pumping blood. The chances are that the same gene will do something negative for its function in the brain. Because after all, at any moment in evolution almost every gene is almost optimal. The point of evolution is that you’re always making small changes in genes. I didn’t mean to say they don’t happen. And then the ones that tend to make the animal live longer or have more children – which is... that’s even more important – are kept. And so. we’re always evolving genes that are on the edge of being as good as they can be. Now, if you mutate a gene to make the... if there’s the same gene in the heart and the brain – and I’m sure there are hundreds of those – and you make one that makes the heart valve more efficient so it can pump more blood, it probably makes some parts of the brain a little less efficient. So there’s always a little bit of loss when you have a gain, almost always. And so, that’s why evolution is slow, because it has lots of genes, all of which are optimized. And we know that most mutations are bad. In fact, a very large proportion of changes in genes are fatal because they prevent the embryo from developing into an adult.

Marvin Minsky (1927-2016) was one of the pioneers of the field of Artificial Intelligence, founding the MIT AI lab in 1970. He also made many contributions to the fields of mathematics, cognitive psychology, robotics, optics and computational linguistics. Since the 1950s, he had been attempting to define and explain human cognition, the ideas of which can be found in his two books, The Emotion Machine and The Society of Mind. His many inventions include the first confocal scanning microscope, the first neural network simulator (SNARC) and the first LOGO 'turtle'.

Listeners: Christopher Sykes

Christopher Sykes is a London-based television producer and director who has made a number of documentary films for BBC TV, Channel 4 and PBS.

Tags: 1940s, Evolution by Gene Duplication, Susumu Ohno

Duration: 3 minutes, 16 seconds

Date story recorded: 29-31 Jan 2011

Date story went live: 12 May 2011