XPost: alt.philosophy, alt.atheism, talk.atheism   
   From: Reanimater_2000@yahoo.com   
      
   "ralph"  wrote in message   
   news:AY2fG0BxBGGEFwai@eddlewood.demon.co.uk...   
   > In message , Immortalist   
   >  writes   
   >   
   >>I believe that probability or "randomness" is a psychic instinct or   
   >>Jungian archetype or mental trend that helps us organize our perceptions   
   >>and memories and most of all our expectations   
   >   
   > And do you think a pollen grain following Brownian movement shares this   
   > psychic instinct?   
   >   
      
   Because most mathematical discussions of algorithms focus on their   
   guaranteed or mathematically provable powers, people sometimes make the   
   elementary mistake of thinking that a process that makes use of chance for   
   randomness is not an algorithm. But even long division makes good use of   
   randomness   
      
   326574 ÷ 47 = 7?   
      
   Does the divisor go into the dividend six or seven times? Who knows? Who   
   cares? You don't have to know; youu don't have any wit or descernment to do   
   long division. The algorithm directs you just to choose a digit--at random,   
   if you like--and check out the result. If the chosen number turns out to be   
   too small, increase it by one and start over; if too large, decrease it. the   
   good thing about long division is that it always works eventually, even if   
   you are maximally stupid in making your first choice, in which case it just   
   takes a little longer. Achieving success on hard tasks in spite of utter   
   stupidity is what makes computers seem magical--how could something as   
   mindless as a machine do something as smart as that? Not surprisingly, then,   
   the tactic of finessing ignorance by randomly generating a candidate and   
   then testing it out mechanically is a ubiquitous feature of interesting   
   algorithms. Not only does it not interfere with their provable powers as   
   algorithms, it is often the key to their power.   
      
   When looking at an E-Coli bacterium swimming around, it is easier to see how   
   randomness can buy food.   
      
   Organisms are problem sovers seeking better conditiions -- even the lowest   
   organism performs trial and error mearsurements with a distinct aim. This   
   image brought to mind Berg's striking film of chemotaxic bacteria. He showed   
   how:   
      
   A bacterium's flagellar motor makes it run and tumble randomly until the   
   bacterium senses a gradient of nutrient. The bacterium then reduces the   
   frequency of tumbling and lengthens the runs towards a greater concentration   
   of nutrient.   
      
   The random element is the tumbling: the new direction of swimming bears   
   little relationship to the previous path before the tumble. And so the   
   cell's path is a random walk unless something else happens. And the   
   something else is simply suppressing the tumbling: When finding mare and   
   more food, the bacterium swims longer on its current straight path. This   
   enables it to home in on the food source, perhaps a decaying morsal whose   
   organic molecules are diffusing away into the water near the bottom of the   
   pond (remember what a sugar cube looks like when disolving in the bottom of   
   a cup, how the sugar gradually spreads out).   
      
   Now most philosophers looking through a magnifying glass at that food   
   finding path would have ascribed intelligence to that purposeful performance   
   of the little bacterium.   
      
   At such a marginal magnification, it would seem to home in on the morsal.   
   But the bacterium has no brain: It's just a single cell with some inherited   
   simple abilities such as swimming, tumbling, and sensing increasing yield.   
      
   One the Most basic form of multicellular creatures, consisting only of   
   SOCIALIZING CELLS sensing each other. Advanced organisms such as the one   
   reading these words comprise many billions of cells that are organized into   
   enormously elaborate structures during the process of development from egg   
   to offspring. Nonlinear mathematics can provide a qualitative sketch of the   
   self organization of a community of cells, as we can illustrate with the   
   help of a strange creature called slime mold.   
      
   The slime mold lies halfway between a collection of single cells and an   
   organism. Like the ant hive Dictyostelium discoideum is a superorganism. At   
   times it is multicellular (with around 100,00 cells), while at others, its   
   cells wander independently. When the bacteria that make up its food are   
   plentiful, individual cells feed voraciously, behaving like solitary   
   wanderers and multiplying by direct cell division.   
      
   Eventually, however, the colony runs short of food. Now the cells "notice"   
   each other. For nonlinear reasons not yet fully understood, certain cells in   
   the colony become active and act as pacemakers, "ringleaders" that send out   
   rhythmic pulses of a chemical called cyclic adenosine monophosphate (cAMP).   
   This is a ubiquitous molecule in biology that acts as a molecular message   
   between neighboring cells. It is a glucose distress signal, announcing they   
   have run out of food.   
      
   This clarion call to close ranks and organize travels at a few microns a   
   second. Cells amplify and pass on the message, a form of feedback mechanism   
   providing the nonlinearity that induces still more cells to hone in on the   
   pacemaker centers.   
      
   There are two additional ingredients:   
      
   Once a cell has released a burst of cAMP it cannot immediately respond to   
   another signal, going into a "refractory state" before returning to an   
   excitable condition.   
      
   The cells also exude another enzyme -- phosphodiesterase -- that destroys   
   cAMP, setting up a gradient of the chemical that provides a signpost.   
      
   The starving cells slither toward the pacemaker cells, in the direction of   
   increasing cAMP concentration. Aggregating populations can produce   
   concentric and spiral waves that bear a compelling resemblance to the spiral   
   waves occurring in the BZ reaction. This is no surprise: though the details,   
   the positive and negative feedback processes are the same.   
      
   Once the cells have formed a slimy mass, they begin to differentiate and a   
   tip forms that secretes cAMP continuously. The whole mass becomes organized   
   into a glistening multicellular "slug," with a head and a tail, that   
   wriggles in search of light and water.   
      
   All in all, it takes several hours for these cells to form this simple   
   organism. Between one and two millimeters long, it crawls along under the   
   leadership of the pulsating source at its tip. It then rights itself to form   
   a hard stalk above which perches a small head containing spores; eventually,   
   the head breaks open and the wind casts its spores far and wide. If they   
   settle in a suitable place, they can germinate and begin the cycle of this   
   strange organism's life anew.   
      
   Since the early part of the century it has been known that the pattern of   
   organization of a living system is always a network pattern. However, we   
   also know that not all networks are living systems. According to Maturana   
      
   [continued in next message]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)