Advanced Nonlinear Dynamics

Posted by Steve Hanna on April 20th, 2007 filed in Technical Tags: physics, quotes, sexified, strange noneuclidean geometry

So, I’m currently enrolled in Physics 511, Advanced Nonlinear Dynamics. The class is quite cool. It is a survey class so doesn’t go into as much depth as I would like, but overall it is quite enjoyable. Thus far we have covered cellular automata, turtle graphs, fractals, neural networks, and more recently genetic algorithms. Actually genetic algorithms are the reason I decided to make this post. For those who don’t know the basics on a genetic algorithm, I’ll break it down here.

1) Pick an entity to be measures (string, program, etc). Actually, have a collection of these entities. (Also known as “modules”)
2) Determine quantitatively a way to evaluate the entity’s usefulness.
3) Apply random mutations, crossovers (reproduction). Then pick the “best” and “worst” entities.
4) Replace the worst entity with the best
5) Repeat 3-5 until an optimal solution is achieved.

Yeah, that was pretty basic and a lot of hand waiving. But it really all boils down to a question a student asked:
“What’s the point of crossovers?”

To which my professor replied:
“The main advantage of sexual reproduction is the emergence of modules.”

There you have it, the main advantage of sex. The sciences have no hope.

But to offer a rejoinder to my own argument, I am reminded of the quote by Richard Feynman:
“Physics is like sex. Sure, it may give some practical results, but that’s not why we do it.”