## Monday, June 20, 2011

### Of physics and biology

John Baez writes about complex systems like biological systems and physical systems such as climate and similar. In a recent post, he had a blurb about one of my favorite topics: the use of statistics in projects.

Now I've always contended that statistics is just a way of abstracting a lot of data into a few values that project managers, process designers, and systems people can use to estimate resources, evaluate risks, and forecast outcomes--all important tasks to be sure.

So, no apologies for using such a tool to reduce the information overload in projects.

But to tell you the truth, I've not done anything with biological or pharmaceutical projects, or climate for that matter.  After reading the excerpt below, I would enter only cautiously!
Physicists love to think about systems that take only a little information to describe. So when they get a system that takes a lot of information to describe, they use a trick called 'statistical mechanics', where you try to ignore most of this information and focus on a few especially important variables.

For example, if you hand a physicist a box of gas, they'll try to avoid thinking about the state of each atom, and instead focus on a few macroscopic quantities like the volume and total energy. Ironically, the mathematical concept of information arose first here—although they didn't call it information back then; they called it 'entropy'.

The entropy of a box of gas is precisely the amount of information you've decided to forget when you play this trick of focusing on the macroscopic variables. Amazingly, remembering just this—the sheer amount of information you've forgotten—can be extremely useful... at least for the systems physicists like best.

But biological systems are different. They store lots of information (for example in DNA), transmit lots of information (for example in the form of biochemical signals), and collect a lot of information from their environment. And this information isn't uninteresting 'noise', like the positions of atoms in a gas. The details really matter. Thus, we need to keep track of lots of information to have a chance of understanding any particular biological system.

So, part of doing biology is developing new ways to think about physical systems that contain lots of relevant information. This is why physicists consider biology 'messy'. It's also why biology and computers go hand in hand in the subject called 'bioinformatics'. There's no avoiding this: in fact, it will probably force us to automate the scientific method!
Bookmark this on Delicious