Random Motion – Welcome

In science, ‘Random Motion’ (or ‘Brownian Motion’)corresponds to motion that is due to the directionless, aimless stirring of molecules. It represents the random, mindless aspect of nature. It is an example of ‘chance’. Its counterpart is of course, ‘necessity’: The action of physical law or the constraints of environment.  Together, so science tells us, they create what we see around us. That’s a bitter pill to swallow for many that hope for a more directed, teleological explanation for all there is. But, ‘chance and necessity’ are indeed very powerful. Think of the functioning of a cell and all the molecules in it. They need thermal random motion to undergo the reactions they need to undergo (try to put your hand in the freezer for a few hours and you know what I mean). But at the same time they ‘know’ what to do, they have direction: So-called motor proteins know where to transport their loads, signal cascades tell the cell to divide and so on. All this is directed by an amazing machinery, which uses multiple levels of ‘necessity’ (from energy molecules called ATP to genetic instructions) to channel randomness into useful directions.

Another example comes to mind: During a recent weekend we walked along a beach on one of the Great lakes. There was a small stream emptying into the lake, cutting the beach at a right angle. It was a stormy evening and some ice flows where on the lake. We went back the next morning and ice and sand had blocked the channel, forcing the little stream to flow parallel to the beach for about 25 meters. Overnight, the beach had completely changed. A week later it was back to normal, battered by several more storms and temperature changes. The beach changes randomly. The random forces of wind, water and ice keep changing the beach on an almost hourly basis. But over the short term the beach stays the same as in some kind of equilibrium. Overthe long term, however, if suddenly the environment changes ( the lake level goes up, the temperature in the winter changes, storms are more frequent) this delicate balance, this fragile state will be upset by necessity. The random forces and the necessity of the changing environment will change the beach forever.

 This is ‘chance and necessity’. Chance provides the drive, and necessity, often born of complexity, provides a type of ‘direction’. Over the long run things change: Mountains are born, species change and complicated molecules learn their dance. If we can’t fathom this, it is probably just because we are blind to the passage of time and the awesome power of chance and necessity.

Welcome to ‘Random Motion’.

Published in: on February 20, 2006 at 10:28 pm  Comments (1)