Just today I stumbled on to an excellent video explaining Bayes’ Theorem. It’s simple and very visual, and makes a nice beginner’s intro. I’d recommend watching it and then reading my explanation of Bayes’ Theorem. Also check out the producer’s other vids, they are very informative as well.
Newsflash: Millions of Americans live in extreme poverty.
Neato summary of the ‘T-Rex collagen controversy.’
Here’s a little story from Ed Suominen, co-author of the new book Evolving out of Eden:
“Ed got introduced to Darwin in a most unexpected way. He certainly wouldn’t have gone out looking to meet him, having been indoctrinated against evolution to the point where it was almost difficult to say the word without negative connotations. It all began from some research about an intriguing way of optimizing design parameters without the engineer having to explicitly specify those parameters: genetic algorithms.
“It’s one form of evolutionary computation, which, as Daniel Ashlock describes in his textbook on the subject,
“‘operates on populations of data structures. It accomplishes variation by making random changes in the data structures and by blending parts of different structures. These two processes are called mutation and crossover, and together are referred to as variation operators. Selection is accomplished with any algorithm that favors data structures with a higher fitness score.’ [Ashlock 2006, 13]
“Sounds innocuous enough, right? But it’s evolution, plain and simple: the “ability to produce new forms, in essence to innovate without outside direction other than the imperative to have children that live long enough to have children themselves.” That, says Ashlock, is the key feature that evolutionary computation tries to reproduce in software (p. 13), and he spends another 500 or so detailed pages showing the various ways it’s been done.
“After reading about evolutionary computation and playing around with demonstrations of it for a while, using readily available open-source software, Ed was soon hooked on its elegance and power. The software sets up an artificial chromosome with each “gene” determining a parameter for some widget you want to design. Then you run a simulation of your widget a few hundred different times, with different sets of parameters specified by random numbers in the genes of each chromosome. Each simulation produces a “fitness” metric, a value that shows how well the widget works in its simulated environment with the particular “DNA” that it was randomly assigned as a starting point.
“Then the fun starts: The widgets mate with each other, crossing over their chromosomes in the same way that those from your parents do in real life, during the production of sperm or eggs in your body. Each widget in the next generation has a randomly shuffled combination of the genes from two widgets in the first population, plus a few mutations sprinkled in. Things are set up so that only the “fittest” widgets from the first generation are likely to be parents of those in the next.
“The result: evolution by a simulated form of natural selection. Ed had been raised believing that Adam and Eve were his ancestors and Darwin was of the devil, but now Darwin had come to his computer. What was happening on the screen before his eyes not only worked but made a lot of sense. He could understand exactly what was happening, because it was computer code, and pretty simple code at that.
“Ed decided that he should learn a little bit about this evolution business to help give him some perspective about how to use this new engineering tool. As things turned out, it wasn’t needed for the parameter-optimization project he had been contemplating, but the hook was set in his mind regardless: It was fascinating stuff, and made so much sense out of everything! Could there really be something to this after all? He started cautiously reading, initially feeling guilt and anxiety about leafing through evolution books as if he were over at the rack of porn magazines instead of the Natural Sciences section of the bookstore. But read he did, and, after a few hundred hours of study, came to the conclusion that evolution was true and Genesis 1-3 was not. It was not an easy or welcome discovery for a fundamentalist Christian to make.”
