Today we talked about what "digital" means. We began by talking about what is information (based on a simplified version of Shannon's development of information theory - one of my favorite expositions of this is Pierce's book). The students had some fun (or maybe it was more me) guessing my age by doing a binary search. I lied about my age, and so they learned an important lesson - that there is good information and bad information! We then discussed how various forms of media - books, audio, images, video - encode their information as sequences of numbers. Pythagoras said more than 2500 years ago that "all is number," and we are coming full circle with quantum physics (which we talked about!). We discussed information vs. knowledge (and how little we really know - think Descartes). Finally, we segued to discussing analog vs. digital computation (and communication). I think this is the part the students enjoyed the most, because they learned how to use an abacus (and why it captures the essence of digital computation) and how to use a slide rule (analog computation). All in all, a fun afternoon.
We never got to the "big" questions that I promised at the beginning of the session: Is the brain digital or analog? Can a human be digitized? Is the universe a giant digital computer? Maybe we will revisit these at a later date. (But there's just too much to cover!!!).