When we conceived of scheme in the 1970’s, programming was a very different exercise than it is now. Then, what generaly happened was a programmer would think for a really long time, and then write just a little bit of code, and in practical terms, programming involved assembling many very small pieces into a larger whole that had aggregate (did he say ‘emergent’?) behaviour. It was a much simpler time.
Critically, this is the world for which scheme was originally designed. Building larger programs out of a group of very small, understandable pieces is what things like recursion and functional programming are built for.
The world isn’t like that anymore. At some point along the way (he may have referred to the 1990’s specifically), the systems that were being built and the libraries and components that one had available to build systems were so large, that it was impossible for any one programmer to be aware of all of the individual pieces, never mind understand them. For example, the engineer that designs a chip, which now have hundreds of pins generally doesn’t talk to the fellow who’s building a mobile phone user interface.
The fundamental difference is that programming today is all about doing science on the parts you have to work with. That means looking at reams and reams of man pages and determining that POSIX does this thing, but Windows does this other thing, and patching together the disparate parts to make a usable whole.
Beyond that, the world is messier in general. There’s massive amounts of data floating around, and the kinds of problems that we’re trying to solve are much sloppier, and the solutions a lot less discrete than they used to be.
Robotics is a primary example of the combination of these two factors. Robots are magnificently complicated and messy, with physical parts in the physical world. It doesn’t just move forward along the ground linearly and without interruption: the wheels will slip on the ground, the thing will get knocked over, etc.
This is a very different world, and we decided that we should adjust our curriculum to account for that. So, a committee (here, Prof. Sussman peaked his hands over his head, which I interpreted to indicated pointy-headedness) got together and decided that python was the most appropriate choice for future undergraduate education. Why did they choose python? Who knows, it’s probably because python has a good standard library for interacting with the robot.