MOTION MOUNTAIN

Chapter 9
CONCEPTS, LIES AND PATTERNS OF
NATURE
Ref. 256
“DieGrenzenmeinerSprachebedeuten die
Grenzenmeiner Welt.*
LudwigWittgenstein, Tractatus, 5.6” “DerSatzisteinBildderWirklichkeit. DerSatz
isteinModellderWirklichkeit, sowiewir sie
unsdenken.**
LudwigWittgenstein, Tractatus, 4.01”
In contrast to mathematics, physics does aim at being a language. But
t is ambitious: it aims to express everything, with complete precision, and,
n particular, all examples and possibilities of change.*** Like any language, physics
consists of concepts and sentences. In order to be able to express everything, it must
aim to use few words for a lot of facts.**** Physicists are essentially lazy people: they
try to minimize the effort in everything they do. The concepts in use today have been
optimized by the combined effort of many people to be as practical, i.e., as powerful as
possible. A concept is called powerful when it allows one to express in a compact way
a large amount of information, meaning that it can rapidly convey a large number of
details about observations.
General statements about many examples of motion are calledrules orpatterns. In the
past, it was often said that ‘laws govern nature’, using an old and inappropriate ideology.
A physical ‘law’ is only a way of saying as much as possible with as few words as pos-
* ‘Thelimits ofmylanguage arethelimits ofmyworld.’
** ‘Aproposition isapictureofreality. Aproposition isamodelofreality aswe imagine it.’
***Allobservationsareaboutchange.Thevarioustypesofchangearestudiedbythevarioussciences;they
are usuallygrouped in the three categories ofhuman sciences,formal sciencesandnatural sciences.Among
the latter, the oldest are astronomy and metallurgy. Then, with the increase of curiosity in early antiquity,
came the natural science concerned with the topic of motion: physics. In the course of our walk it will
become clear that the unusual definition of physics as the study of change indeed covers the whole set of
topics studied in physics. In particular it includes the more common definition of physics as the study of
matter,itsproperties, its componentsandtheirinteractions.
**** A particular, specificobservation, i.e., a specific example of input shared by others, is called a fact, or
in other contexts, an event. A striking and regularly observed fact is called a phenomenon, and a general
observationmadein many differentsituations iscalled a(physical) principle.(Often,whenaconceptisintroducedthatisusedwithothermeaninginotherfields,inthiswalkitisprecededbythequalifier‘physical’
or ‘mathematical’ inparentheses.)Actionsperformedtowardstheaimofcollectingobservationsarecalled
experiments. The concept of experiment became established in the sixteenth century; in the evolution of a
child,it canbestbecompared tothat activitythat hasthesame aimofcollecting experiences:play.
Motion Mountain – The Adventure of Physics copyright © Christoph Schiller June 1990–November 2015 free pdf file available at www.motionmountain.net