MOTION MOUNTAIN

the story of the brain 245
Challenge 246 s
Are you able to say how many bits are necessary to define the place where you live?
Obviously, the number of bits depends on the set of questions with which we start; that
could be the names of all streets in a city, the set of all coordinates on the surface of the
Earth, the names of all galaxies in the universe, the set of all letter combinations in the
address. What is the most efficient method you can think of? A variation of the combination
methodis used in computers. For example, the story of the present adventure
required about five thousand million bits of information. But since the amount of informationinastorydependsonthesetofquestionswithwhichwestart,itisimpossible
todefineaprecisemeasureforinformationinthisway.
Vol. I, page 368
Challenge 247 s
TA B L E 19 Some measures of information.
Kind of information
Amount
Wordsspokenonanaverage daybyaman c.5000
Wordsspokenonanaverage daybyawoman c.7000
Bitsprocessedbytheears
1to10 Mbit/s
Lightsensitivecells perretina(120million rodsand6million cones) 126⋅10 6
Bitsprocessedbytheeyes
1to10 Gbit/s
Wordsspokenduring alifetime(2/3timeawake,30wordsperminute) 3⋅10 8
Wordsheard andread during alifetime 10 9
Letters(basepairs)inhaploidhuman DNA 3⋅10 9
Pulsesexchanged betweenbothbrainhalves every second 4⋅10 9
Bitsinacompactdisc 6.1⋅10 9
Neuronsinthehumanbrain 10 10 to10 11
Printed words available in (different) booksaround the world (c.100⋅10 6 c.5⋅10 12
booksconsistingof50000words)
Memorybitsinthehumanbrain >10 16
Imagepixelsseeninalifetime(3⋅10 9 s⋅(1/15 ms)⋅2/3(awake)⋅10 6 (nerves10 tothebrain) Ref. 248
Bitsofinformationprocessedinalifetime(theabovetimes32) 10 19
The only way to measure information precisely is to take the largest possible set of
questionsthatcanbeaskedaboutasystem,andtocompareitwithwhatisknownabout
thesystem.Inthiscase,theamountofunknowninformationiscalledentropy,aconcept
thatwehave already encountered. With this concept you should able to deduce yourself
whether it is really possible to measure the advance of physics.
Since classification or categorization is an activity of the brain and other, similar classifiers,information
as definedhere is a conceptthat applies to theresult of activities by
people and by other classifiers. In short, information is produced when talking about the
universe.
Information is the result of classification.This implies that the universe itself isnotthe
same as information. There is a growing number of publications based on the opposite
of this view; however, this is a conceptual short circuit. Any transmission of information
implies an interaction; physically speaking, this means that any information needsenergy
for transmission andmatter for storage. Without either of these, there is no information.
Motion Mountain – The Adventure of Physics copyright © Christoph Schiller June 1990–November 2015 free pdf file available at www.motionmountain.net