*

How scientific theories are invented and Early history of Science

Part 1

byPer Arne Bjrkum *Spring 2010NTNU

*Dean at the Faculty of Science and Technology,University of Stavanger per.a.bjorkum@uis.no

IFEL 8000

Litterature

A Selected Hisotory of ScienceTAPIR, 165 pages100 NOK

By Per Arne Bjrkum

Annerledestenkerne - Kreativitet i vitenskapens historie av Per Arne Bjrkum

Universitetsforlaget, 2009. 3. utgave

For those of you who read norwegian420 pages439 NOK

*History of science is used to illustrate how theories are constructed and tested Philosophy of science is in these lectures integrated with history of natural science.

History of science also illustrates the dynamic aspect of knowledge and introduces us to scientific debates how they evolvedand ended including discussions between paradigms

Why history of Science?

The climate debate

A discussion between paradigmsCurrent debate.

*

Although the Scientific Method is basically unchanged since 1600 AD, the philosophy of science has changed.

The philosophy of science is more than the Scientific Method,

It also includes metaphysical/speculative aspects (philosophical paradigms).

The philosophy/metaphysics (paradigm) put some constrains to the starting point (i.e. the basic assumptions and concepts) in search for new knowledge.

The philosophy/metaphysics is strongly influenced by the culture (i.e. tradition/ideology/religion) and ithas changed with time! (as will be shown).Why history of Science? contin.

*Why study the early history of science(prior to 1600AD) the ancient Greek philosophers?

-Their contribution are decisive (as we see it) for the development of the Scientific Method (and our current view on how nature works)

- They gave us some of the mental tools (concepts), and provided us with an philosophical/metaphysical approach to understand nature that has proven decisive

- This approach (philosophy) did not fully develop in other cultures.

* 1800-1950 AD 1600-1800 AD 1400-1600 ADContribution to natural science. up to 1950Human Accomplishment, C.Murry, 2003 72% of the significant people in science from 1400 -1950 are from Britain, France, Germnany and Italy (four countries!)Whether meassured in people or events, 97% of accomplishment in scientific inventories occured in Europe and North America

*Human Accomplishment, C.Murry, 2003

*What is the role of

Religion PhilosophyMetaphysicsMystics.. Goverment.?

The enigma is: Why did the Chinese, the Arabs (Muslims..600 AD), and the Indians not make any significant contribution to science up until 1900 AD?

There were sufficient interaction. ..and the genius..people that make a differenceentangled

*No one is born a genius! Genius is created (by themselves)by spending more time (~3 x)than otherscultivating and developing their Talent(s) About science and genius."nerds"

much more self-study (not on thesyllabus)

..fascinated by alternative reading

*Maxwell was flabbergasted by the fact that somany talented or learned individualsdid NOT (!!)contribute to something new in science.On being talented

The history of science (.) has to explain unsuccessful inquiries, and why some of the ablest men have failed to find the key to (new) knowledge

J. C. MaxwellAn enigma

*How are new theories received?Science is about developing new knowledge, new theories, but..

*Ohms Law (1826)U = R IA new theory

*Ohm's conclusions were poorly received by the intellectual elite who sent a letter to the Ministry ...He was fired and lost his job in "lower secondary school"NOTE: This had nothing to do with the Church. A physicist who preaches such heresy is not worthy of teaching science"

*New knowledge (growth in science) happens when different phenomena (like electricity and magnetism), at a certain point in the development considered to be separate fenomena (non-connected), become related*

What is new knowledge and what do we mean by growth in science..? *Defined by Leibniz and named: relationalism

*MagnetismElectricityElectromagnetismDeeper/underlying relations

This relationship points to an underlying not so obvious property (electromagnetism)

*Descartes1596-1650Leibniz (1646-1716)Cartesian coordinates 1637 The idea:Looking at a flyin the roomSpace becomes related to numbers!New knowledge and relations in mathematics

*The scientific methodThe modern scientific method (17th century) is

mathematical description (Galileo) of hypotheses that can be - tested by experimentation/experience (Galileo) in such a manner so that others can test/check, which requires detailed description (Boyle,1660, but also Gilbert,1600!) De Magnete, 1600

*There is no scientific method for how to come up with new ideas or for how to solve the problem!!

The scientific method is only for for testing the invented (by the scientists way of thinking!) proposals/hypotheses/theoriesOn the scientific method

*The theories we have abandoned today: The phlogiston theory (air as an inert element) The theory of PxV = k (and the springness of the air)- Daltons theory of atoms (quantitative theory!) - The theory of heat (caloric: a fluid-like substance) Newtons theory of gravitation (not totally free of ether and God) - Bohrs theory of atoms (hybrid: Newtons physics + quantum theory)were all well justified/reasoned (for their time)- they were logical they were based on supporting observations (evidence) hence, they were considered to be correct (proven)

Developments after 1600How is this possible?- they were no less intelligent 400 years ago, and they worked in accordance with the modern scientific method ...A mechanical invisible something!

*Sadi Carnot 1796-1832Knowledge and Technology developmentEmipircal approachTheory driven developmentTechnoloogyScience

What isthe status of scientific facts?

*Facts are theory-biased, and theory is a temporary"truth".Theory determines what one can see (Einstein)On facts in science.."When great breakthroughs are made, a truly great discovery, it means that the experts were wrong and that the facts, the objective facts, were different from what the experts believed they were. K. Popper, A World of Propensities, 1995

*AtomElectron,MassPressureVelocityAcceleration GravitationSpaceProton (particle)NeutrinoIonsAirViscosityCurrentResistanceHeatEnergy quantumEM wavePhotonElectromagnetismQuarksSuperstringsEtherCrystalline shellEpicircles/cyclesNatural habitatCentre of the UniverseDark energyBallStoneHouseWaterNew knowledge requires new concepts!

How do (new) concepts arise?

What comes first?The Concepts? The Observations?

How do we get started? Concepts

*AtomElectron,MassPressureVelocityAcceleration GravitationSpaceProton (particle)NeutrinoIonsAirViscosityCurrentResistanceHeatEnergy quantumEM wavePhotonElectromagnetismQuarksSuperstringsEtherCrystalline shellEpicircles/cyclesNatural habitatCentre of the universeBallStoneHouseWaterHow do concepts arise?We are free to choose all concepts, even those that are closest to our experience, and there "is no inductive method that can lead to the fundamental concepts used in natural science". (Einstein, Autobiographical Notes, 1953)The way they (the concepts) are created is unexplained, and thus there is "no method that can be learned. (Einstein, Ideas and Opinions, 1954)Close to our sensesMore abstractand not supportedby the senses

*The concepts that arise in our thoughts and our forms of expression are all, logically, free creation of thoughts that cannot be attained through inductive thinking or observations." Einstein, Ideas and Opinions, 1954 We are free to choose the concepts (Einstein)Even the concepts that are closest to what we sense, come about in this way (Einstein)The origin of concepts

*"Concepts that have proven useful to keep things in order may easily gain so much authority over us that we forget their earthly origin and accept them as immutable facts"

(from Einstein's article: Ernst Mach, 1916).The "illegitimate" authority of the conceptsBecause they are part of the logical structure which is empirically supportedA warning from Einstein ..

*On the need for logical orderMan (us) is driven by an intense logical need to create (logical) order in the part of nature/life we have been interested in and Man has always managed this i.e. different solutionsIn different ways

*The Aristotelian physics and theAristotelian view of the world were..

logical (= reasonable = true = real)butnevertheless wrongon all counts!

*Logic gives 100% certain knowledge, but it does not state anything about reality (cf. mathematics, proof)

Observations give information about reality, but they are not 100% certain (cf. theories of nature, evidence)Logic versus observation

*Euclids mathematics is logical, but not logically nessesaryEuclidNon-Euclid

*"What is genuinely new cannot be deducted from logics, only (first) grasped intuitively." K. Popper

*The logic based on the premises (and concepts), and is taken from theories which in turn determine what becomes fact !Logical circle argumentation Einstein, PopperAll points of view are logicaland thus well founded.

*Scientific publications

Pasteur This statement covers up the speculative foundation And it has become a model for how to write scientific papers

"Make it appear unavoidable

*"Theories can never be (logically) deducted from observation statements, nor justified rationallyby these." Popper

*New knowledge does not arise "through observations or experiments" but when a "critical examination of our theories" is undertaken.

Popper, Conjectures and Refutations, 1989

*MetaphysicsA Knowledge MetaphorlogicsValue choiceControlling principlesThe island of knowledgeParadigm

*A Knowledge MetaphorlogicsMetaphysical values (the foundation of the paradigm): nature is understandable/rational, symmetry, harmony, continuity (no jumps!?), causality, simplicity etc., mathematical description, geometries (circles?), jumps (quantum mechanics)?

God is a geometer (Platon/Ptolemaios, Copernicus; Galilei, Kepler, Einstein)

Nature is about number/relationships (Phytagoras)The island of knowledge

*MetaphysicsA Knowledge MetaphorlogicsValue choiceControlling principles?New island (paradigm)

The island of knowledgeThe transition is not an actof logic, - it is a choice a private choice inspired (determnined?) by metaphysical valuesParadigm

*MetaphysicsA Knowledge MetaphorlogicsValue choiceControlling principlesThe island of knowledgeThe inner structure of a theory opens for ananother metaphor(to be shown later)Paradigm

*logicsThe paradigmIt is a filter on information/datainformation irrelevantinformation

*logicsThe paradigm (what you see)It is a filter on information/data and it determines what you see (read: understand)information irrelevantinformation?It is the theory that detemnines what we can se Einstein

*Arthur C. Clarkes Law (1923): When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong

*A Theory- elements and its structure Model for constructing a scientific theory (short introduction)

*You know the elements involved: Concepts, definisjonion, matemathics/logic, observations/experimentsand its structure

but

what about the routes of thought and the activities involved?

Model for constructing a scientific theory (short introduction)

*

is a theory

Discovered? or Invented? Model for constructing a scientific theory (short introduction)and

*Einsteins letter to a friend May 7, 1952A theory is invented.Because there is no logicalroute from observation to a theory

*Invention is not the product of logical thought, even though the final product is tied to a logical structure Einstein, Autobiographische Skitzze, 1956(8 pages, an additional to his Autobiographical Notes, 1953) Einstein: and the role of logic in creating new theories (invention of theories)

*Einsteins letter to a friend May 7, 1952Where he explain with reference to this figure (in black) how scientific theories are inventet.This outline is based on G. Holtons The Advancement of Science, and Its Burdens, 1998, p. 28-56). A theory is invented.

*Einsteins letter to a friend May 7, 1952Where he explain with reference to this figure (in black) how scientific theories are inventet.This outline is based on G. Holtons The Advancement of Science, and Its Burdens, 1998, p. 28-56). E (experience)J (a-logical/creative jump)A, assumptions (concepts and definitions)P ( predictions) D, The logical deductive pathEinstein. Inner perfection(the structure and elements in the theory), and external validation (observations)The model (its dynamic structure) (To be explained in detail - later)(axioms)

*Einsteins letter to a friend May 7, 1952Einsteins two main perspectives (inner perfection and external validation)Inner perfection(the structure and elements in the theory),external validation (observations)

*E1E2E3E4Experience?A Theory: Elements and structureEinstein: It starts with experience, and ends with it

*E1E2E3E4ExperienceEinstein on observations/experiencewhat is it?It Contains/includes::Mutliplicity of immediate sense experience experience given to ustotality of emipirical factstotality of sense experiencea labyrint of sense impressionsthat can be the result of illusions or hallicunations(!)

For Einstein Science is the attempt to make the chaotic diversity of our sense-experience to a logical uniform (unified) system of thoughtA Theory: Elements and structure

*Assumptions (concepts, definitions)A1A2A3E1E2E3E4Experience?A Theory: Elements and structureAnA-logical step (a jump)Filter (personal)

*Assumptions (concepts, definitions)A1A2A3E1E2E3E4Experience?A Theory: Elements and structureEinstein:We pay attention on certain repetedly occuring complexes of sense impressions and relating them to a concept , mental knots or mental connections between sense impressions, and is primary if close to sense experience. But we select the concepts without some logical necessity.All concepts,even those which are closest to our experience, are (from a the point of wiev of) logical freely chosen conventionsAnA-logical step (a jump)Filter (personal)

*Assumptions (concepts, definitions)A1A2A3E1E2E3E4Experience?Basic elementsNB:There is no logical relation between the basic elements!A Theory: Elements and structureAnA-logical step (a jump)Filter (personal) Basis:Metaphysical Philosophical(Paradigm)

*Assumptions (concepts, definitions)A1A2A3E1E2E3E4Experience?Basic elementsNB:There is no logical relation between the basic elements!A Theory: Elements and structureAnA-logical step (a jump)Filter (personal) Basis:Metaphysical Philosophical(Paradigm)Consists of the greatest possible sparsity of the of logically independent elements (basic concepts and axioms)Assumptionsit is the grand object to all theory to make these irreducableelements as simple and as few in numbers as possible Ideas and Opinions,

*Assumptions (concepts, definitions)P1P2P3Logical/analytical/mathematicaldeductions A1A2A3E1E2E3E4Experience?Basic elementsNB:There is no logical relation between the basic elements!A Theory: Elements and structureAnA-logical step (a jump)Filter (personal) Predictions (to be tested)

*Assumptions (concepts, definitions)P1P2P3Logical/analytical/mathematicaldeductions A1A2A3E1E2E3E4Experience?A Theory: Elements and structure

Logical thinking is nessesarily deductive which requires much intens, hard thinking

The structure of the system is the work of reason (which can be learned at school).

AnA-logical step (a jump)Filter (personal)

*Assumptions (concepts, definitions)Predictions or Statements about natureP1P2P3Logical/analytical/mathematicaldeductions A1A2A3E1E2E3E4Experience?A Theory: Elements and structurethe relations between the concepts appearing in P (predictions) and E (experience) are not of a logical nature. The theory must not contradict empirical facts (external validation). AnA-logical step (a jump)Filter (personal)

Einstein: It starts with experience, and ends with itTheoryExperience

*Assumptions (concepts, definitions)P1P2P3 A1A2A3E1E2E3ExperienceA Theory: Elements and structure.. If prections are not verifiedIf NO!!!, -one solutions could be to add the number of assumptions, AnE3 = NO!!!E4

*Assumptions (concepts, definitions)P1P2P3A1A2A3E1E2ExperienceA Theory: Elements and structure.. If prections are not verifiedIf NO!!!, -one solutions could be to add the number of assumptions, Ana1a3But it increases the number of assumption and goes againstkeep it simple-principlea2(ugly)E3E4E3: NO!!!

*Assumptions (concepts, definitions)P1P2P3A*1A*2A3E1E2ExperienceA Theory: Elements and structureIf NO!!!, evaluate the whole set of assumptions and definitions Ana1a2E3: NO!!!E3E4a3A better (?) alternative

*Assumptions (concepts, definitions)P1P2P3A1A2A3E1E2E3E4Experience?A Theory: Elements and structurePnPredictions of unseen/unobservedfenomena (relations).Keep it simple Explain as much as possible with as little as possibleAnA-logical step (a jump)Filter (personal) Popper: this is a good theory

*-There no logical route from one assumptions to one observation

-There is a logical link from the wholde set of assumptions to the observations

-If the theory fails, it is the whole set of assumptions (as a whole) that fail.

-It is not possible to identify which of the assumptions that has to be replaced, - or modified.

About the logical routes in a theory

Logical routesNoYes

*Assumptions (concepts, definitions)Predidictions or Statments about natureP1P2P3Logical/analytical/mathematicaldeductions A1A2A3E1E2E3E4Experience?Basic elementsNB:There is no logical relation between the basic elements!Summary: A Theory: Elements and structurePnPreditions of unseen/unobservedfenomenaAnA-logical step (a jump)Filter (personal) a1a2

*Teoriene blir mer og mer abstrakt og kompakt, noe som er synlig i den matematiske formalismen. Det blir stadig vekk en lengre (matematisk) vei mellom begrepene og observasjonene, slik Einstein selv var inne p.The (mathematical/logical) distance between (abstract concepts) and observations (what we sense) is increasing, as Einstein claimed.

Concepts and sensory proximity

*A1A2A3AnThe basic assumptions are logically islolated from each other.

Implications:

It is therefore not possible to present a logical justification for neither each assumption/definition nor the whole set of assumptions/definition (why these and not others)

Note: there is no knowledge in a definitions, it serves in combination with other definitions and assumptions as a starting point for possible knowledge

*P1P2P3E1E2E3E4ExperienceThe (initally) logically independentassumptions (and definitions)become logically related/connected in this part og the structure.

Also here, the cause and effect relationships emerge!

This can give the (wrong) impression that the cause and effect relationships emerging in in the deductive step are - logically connected (from the start)!!NB:The assumptions (and definitions) become logically relatedlogicA1A2A3An

*MetaphysicsA Knowledge MetaphorlogicsValue choiceControlling principlesThe island of knowledgeThe inner structure of a theory opens for ananother metaphor(to be shown later)Paradigim

*The Inner Structure of Knowledge?What do we mean by increased knowledge?The trunkMethaphysical foundations

*The Inner Structure of Knowledge?What do we mean by increased knowledge?TrunkEarly stage: the knowledge was isolated knowlegde, that is: not related Methaphysical foundations

*And how will the final tree look like?

*You cannot watch the world and move (logically) down the braches and down to the trunk - and discover the connected branches that way..Observations

*ObservationsYou have to remember the observation, and make a jump to the lower part of the tree and try to invent concepts and a way og thinking thatby deductive thinking leads you up the brache and hopefully connect well to the observation.

Then you have made a new brach to the tree, a branch that may not survive. is may have been scion... (norsk: en podet grein)ConceptsDefinition

*ObservationsA scion?There is no way to tell a priori because you do not know how the tree eventually will look like!

*And is it one tree (the theory of everything)? The metaphysical hope is that we will end up with one tree(superstring theory?)

*NewtonEinsteinParadigm shiftsNew basic assumptions and definitionst (the roots)A1, A2,.A*1, A*2, .(Different property of space and time)

*logicMetaphysicsValue choiceControlling principlesObservations (with filter)

*Invention is not the product of logical thought, even though the final product is tied to a logical structure Einstein, Autobiographische Skitzze, 1956(8 pages, an additional to his Autobiographical Notes, 1953) Einstein: a theory is invented and

*Einsteins figure and the tree metaphor

What about the cause and effect(causality) relationships in science?

A basic conpsept

*Cause and effect relationsCausal relationsHume (and Mach) saw causal relations as "necessities only existing in consciousness but not in objects".

We depend on cause-effect relations in our endeavour to understand.

According to Kant we have no choice.

We must ensure that our perception of the world is "causally arranged" (regardless whether nature is or not).

These choices may easily be the wrong ones ...

*Cause and effect realtionships..exampleBlood and feaver Galen ca. 150 AD Treatment with bleeding becasue according to Galen (ca. 150 AD), who had it from Empedokles, the body heat stems from the blood, hence the only(?) sensible thing to do was to bleed oncetwice Case 1

*Feaver and bacteria Semmelweiss ca. 1850 Blood and feaver Galen ca. 150 AD bacteria were thought to be an effect of being sick, and not the cause of it and besides: how could the small bacteria kill a big man?

So why should the doctors have to wash their hands thoroughly?

The doctors were not willing to clean their hands properly and the death rates during birth at hospitals could reach up to 30% (and only ca. 1% at home!)Why did they not wash their hand with clorine as suggested by Semmelweiss?Well, they had god reasons. Treatment with bleeeding becasue according to Galen (ca. 150 AD), who had it from Empedokles, the body heat stems from the blood, hence the only? sensible thing to do was to bleed oncetwice Case 1Case 2Cause and effect realtionships..example

*Cause and effect realtionships..Feaver and bacteria Semmelweiss ca. 1850 Blood and feaver Galen ca. 150 AD bacteria were thought to be an effect of being sick, and not the cause of it and besides: how could the small bacteria kill a big man?

So why should the doctors have to wash their hands thoroughly?

The doctors were not willing to clean their hands properly and the death rates during birth at hospitals could reach up to 30% (and only ca. 1% at home!)Why did they not wash their hand with clorine as suggested by Semmelweiss?Well, they had god reasons. Treatment with bleeeding becasue according to Galen (ca. 150 AD), who had it from Empedokles, the body heat stems from the blood, hence the only? sensible thing to do was to bleed oncetwice Case 1Case 2

*It is "the theory or the law that establishes the logical relation between cause and effect" Popper, Objective Knowledge, 1979.

How things are connected, i.e. the causal (meaningful) relations, is determined by theory.

What we find reasonable and thus believe depends on the prevailing theories or ideas we have on nature at any time.

There is logical circularity in our reasoning, and we should bear this in mind.

It is not only "the others" that are in such a (closed) logical circle of thinking.

Cause and effect relationships

*logicsThe paradigmIt is a filter on information/dataand what you can see (with the theory)informmation

*Symmetry..cause and effectHow could electrisity be affected by magnetisme? And as later shown by Faraday vice versa? See page 146-161 in the compendium

A breif look at the properties of cause and effectrelations i natural scienceExamples

*MagnetismElectricityElectromagnetismCause and effect: A deeper/underlying connection ?

*"Concepts we must consider essential, for example causal relations, cannot be achieved based on the information provided by our senses" Einstein, Ideas and Opinions, 1954. Causal relationships and concepts

*P1P2P3A1A2A3E1E2E3E4ExperienceAnThe assumptions (and definitions) become logically relatedThe cause and effect relationships emergehere!

*It is the theory or the law that constitutes the logical link between cause and effectPopper, Objective Knowledge, 1968

Causal relationships do not have an independent outside the theory (scientific) justufication other than that it according to theory make sense (i.e. pleases the reasonable mind)

To remind you..

*Friction (the fenomenon) produces heat! (the fenomenon)

So: What is heat?Cause and effect

*Thompson, 17981753-1814The caloric theory (the heat was a substance - with some mas - hidden within the body, by ut was liberated upon agitation. But Thompson saw that the energy liberated appearde to be unlimited. As long as agitation continued, heat was produced.

He writes:Drilling on metalExperimental Enquiry Concerning the Source of the Heat which is Excited by Friction, 1798

*Vison: light- from the eye - or towards the eye??

The light that is emitted from the eye, moves in a straight line Euklid, Optica) HENCE: Speed of light must be extremely fast because when we open oureyes, far away objects like the stars - are seen at the same time as the closer objects!!

*Leonardo da Vinci (1452 -1519)CreativityLateral thinking

*Innovative combination (of explanations and drawings)Leonardo da Vinci (1452 -1519)New relations.

*How it started

*It stared with Thales (the first natural philosopher) This culture believed it was possible for man to understand nature. It was their paradigm.

They established what we call rationalism (the trust in the faculty of reason)

This was what was radical about this culture. This pre-Socratic culture was the source of inspiration for the scientists who rebelled against Aristotelian physics in the 17th century. How it started seventh century BC)

*Perhaps an even more important and lasting feature of the culture Thales introduced, also called the Ionic culture, was that the pupils were encouraged to critique what the master had presented. How it startedFlat Earth (a drum)Floating on waterThales: flat earth

*The flat earth myth was introduced i 1828 by the essayist and novelist Irving Washingtons: A History of the Life and Voyages of Christopher Columbus It was a fictionIn 1945 the Historical Association listed "Columbus and the Flat Earth Conception" second of twenty in its first-published pamphlet on common errors in history! It was misconceived by many to be historically correct!!The flat Earth myth..

*Eratosthenes (276 BC-194 BC)

*Anaximanders explanation simply removed the need for anything to keep the earth in place because

"the Earth is held up by nothing, but remains stationary owing to the fact that it is equally distant removed from all other objects". On the earths place in the world..Popper felt this was "one of the boldest, most revolutionary, and most portentous ideas in the whole history of human thoughts." (Conjectures and Refutations, 1989).

*The problem of change.Tha basic question was: can we trust our senses?

*Heraclitus maintained that everything in nature keeps changing (panta rei, i.e. everything flows or is in flux), but we do not see it (for example that material objects are also undergoing continual change). According to Heraclitus (he is unclear, and is often called "the obscure"), nature hides its true self ("nature loves to hide"), and the changes we observe are not nature's real changes.

Changes due to ageing are not change at all to (the obscure) Heraclitus, because: "As the same thing in us is living and dead, waking and sleeping, young and old ... all is the same".A paradoxial logic!The problem of change.

*Parmenides went to the opposite extreme. He rejected all change, including what we see.

What we sense or see are not real changes, according to Parmenides. They are illusions. (Zenons paradox)

The problem of change.

*A Solution: Unification of both perspectives:

Changes do occur, but something remains unchanged

Empedocles believed that nature consisted of a fixed amount of each of the four immutable elements air, fire, water and earth, which in different mixtures made up everything in nature.

The problem of change.

*The atomists (Leucippus/Democritus) attacked Parmenides hypotheses and asserted that we actually do see things moving, ergo denying it must be wrong.

They thus chose to trust their senses.

Hence by introducing something immutable in what is changeable (the atoms) and by allowing empty spaces in nature, they laid the foundation for modern science. The problem of change. .an alternative solution

*

Aristotle added a fifth (strange) element: the ether (aether) only present beyond the moonIt was removed from science by Einstein (1905)The ether (concept) was important for Newton, and also for scientist during 19th century The problem of change.

*Pythagoreans had geometrical pictures of numbers (the numeral 1 was a dot, numeral 2 was lines, numeral 3 was triangles, numeral 4 was pyramids and so on).

This same geometrical aspect of mathematics also inspired Copernicus, Brahe, Kepler, Galileo and also Newton en even Einstein! Newtons main work, Principia, (1687) used Euclidian mathematics, i.e. geometrical mathematics, to prove his hypotheses in physics (gravitation).

Pythagoras was looked upon as a God. Rumours (after his death) had it he was able to walk on water, still the wind, rise from the dead (from a cave), his mother was named Parthenis which means virgin. Pythagoreans (lived at the same time as Pre-Socrates)The problem of change. and mathematics..

*That something is constant/conserved in nature, and are the foundation on which all science is built (i.e. the conservation laws). (the unchangeable in everything that changes)

On the other hand, if nothing changes (as Parmenides claimed), there would be no need for natural science whatsoever. The problem of change and modern science

*The pre-Socrates.and impact on modern scienceTheir contribution (NB: forgotten from around 300 AD, and re-surfaced in the 1400s AD)

Nature was ruled by laws The laws could be understood by the faculty of reason They believed in and were looking for simple answeres They encuraged and valued critisism They observed nature (They were trying to apply mathematics to nature) What they did not do, was to perform experiments

*This circle was the time paradigm. Aristotle shared this belief, "because even time is assumed to be a circle" (Physics). The circle was the ideal. It has a perfect shape, and has no start or end! The circle also explained natural movement "There is a circle in everything that has natural movement", (Physics), and this circle has no start or end.

Hence, a planet can be in a movement without change place in the universe.The role of the circle paradigm in the conception of time in early philosphyNB: In the Christian tradition, the prevalent perception was that time was linear in natural consequence of the birth of Christ.

*Aristotle: circular time and implication for his thinking- According to Plato, and later Aristotle, the best period was just now ("The Golden Age"). The world could not be better than it was just now (when Aristotle lived).

- When it came to devices that made for a good life "almost any requirement for comfort and social improvement has already been ensured" because "everything of such a nature has already been produced" (Aristotle, Metaphysics).

*Aristotle: circular time and implication for his thinkingContBecause time was circular/cyclical, everything would repeat itself. Including thought.

"The same ideas, one must believe, recur in men's minds not once or twice but again and again" (Aristotle, On the Heavens).

Every object/technology had already been

"invented many times, and again in the course of time, in numbers beyond counting" (Aristotle, Politics).

Now one was leaving this the best period of the cycle This was a development (i.e. decay) nobody could prevent. Golden agedecay

**Thales ( 640-540)Anaximander (611-540)Pre-Socratic philosophers (in Greece "before" Socrates, Plato and Aristotle)Nature is comprehensible for human thought. Sought the immutable in the changeable and what everything had been made from (primary matter)This primary matter was water (Thales), or something unknown we cannot observe (Anaximander)Parmenides (540480)Heraclitus (540-470)Reject Thales and Anaximander by asserting that nothing changes, it is senses that deceive us (Parmenides), or everything, absolutely everything, is in continual change, nothing remains the same ("you cannot step into the same river twice"), thus there is nothing immutable no primary matter (Heraclitus)Empedocles (495- 435)Sought to unite 1) and 2) by accepting change, but believed that nature was built of four primary matters: earth, water, air and fire, which in different mixtures made up everything we can sense Democritus (470-380)Changes are real, but something immutable exists that builds nature and which is invisible: (indivisible) atoms (made from a a primary matter) in various forms that always move in a vacuum These philosophers were "the first"(?) rationalists, i.e. the first to believe in the feasibility of thought being able to understand nature (it was not seen as mystical), and they sought the simple answers (as modern science does).Modern natural science builds on these philosophers of nature in addition to Plato, but not Aristotle!Pythagoras (560-480)A special "religious" school which believed that the primary matter of nature is not material elements, but abstract mathematical relations (everything was the relation between integers)1)2)3a)3b)4)Belong to the same school of philosophy18.01.2006To be read

**Aristotle (384-322)

The actual substance, primary matter", what is immutable/eternal, is not material, or relations between integers, but ideas. What we sense is merely a pale and fleeting shadow of the ideas. Knowledge is insight into the ideas, and they can be viewed through thinking/contemplation. Prior to birth the soul has knowledge about everything (i.e. the ideas, because the soul was one with the ideas before birth). This knowledge is lost at birth when the soul is divorced from the ideas and dwells in the perishable body. Recognition of thoughts is proof of new contact with "the forgotten" ideas. Learning therefore concerns recognition through intuition.Examples of ideas are perfect geometrical shapes (triangle, circle, cube etc. which we can only make or draw approximations of). Knowledge about what is true is thus insight into the perfect and immutable ideas, and we seek this knowledge because we have inherent yearning causing us to seek what is ideal and valuable. Only a few, however, are able to achieve true knowledge. Plato was not interested in the material and sensory world. Plato was important for Augustine's teachings (400s) , but was "forgotten" from around the 13th century (Aristotle gained importance due to Aquinas)), but he had his renaissance in the 16th century and was important for the emergence of modern science. Aristotle, Plato's student, rejects Plato's teaching about ideas, and claims that only individual objects (matter) exist. The important thing is the shape of objects (not what they are made from). The idea of a horse as an abstract phenomenon arises after many sensory impressions of individual horses (what is common, the essence of horse, becomes its shape). We abstract what is general (the shape of the horse) from what is incidental (the colour of the horse). Knowledge is insight into what is general. Aristotle observed parts of nature (animals), but did not carry out physical experiments (that would be forcing motion on nature, and would give no information about natural motions). He rejected the idea that mathematics (numbers) had anything to do with the material world (hence mathematical physics as introduced by Galileo was impossible for him). He rejected the existence of a vacuum ("nature abhors a vacuum"), thus he rejected Democritus' idea of atoms which required a vacuum. Aristotle believed that the material/sensory world consisted of different mixes of the elements (he had this idea from Empedocles) earth, water, air and fire (on earth), and what was outside the moon's sphere consisted of a substance he called ether (without mass!). The material world was animist, i.e. it had properties such as eagerness (a stone would be urged toward earth because this was its natural habitat). Time was cyclical (circular idea of time, everybody would be born again and live the same life again forever). According to Aristotle his period was "the Golden Age", the peak of technology. Further development was impossible! Thus knowledge was not sought to exploit nature (more than what was already the case). The world was not created, but had always existed, and had been put into motion (but was not created) by a prime mover" (an "impersonal" God). He believed that the earth was the centre of the world and at rest (did not spin around its own axis) and that the planets and the sun travelled at constant speeds and in circles (an idea from Plato!) around the earth. Aristotle replaces Plato from the 13th to the 17th century as the authority on natural philosophy (Aristotle's writings were studied to gain knowledge about nature). Plato and Aristotle (brief summary with emphasis on what is important for knowledge on nature)Plato (427-347)To be read

*An important fruitful guiding principle in natural scienceWhat appears to be complicated does not require a complicated starting point (i.e many basic concepts, definitions)Ockhams razor - but used since Thales; the first natural philosoper"It is vain to do with more what can be done with less after William Ockham, c. 12851349, English logician and Franciscan friar waterThere is no scientific rationale for this principle, but it has been a very useful principle. Explain as much as possible with as little as possible

*Platons orderto Aristotle:Use circles and constant speed for the plantesAristotle: the universeEarthEtherKeep it simplePlanets, sun and stars

*Earth/stonewaterfireAristotles sublunar world (place for degeneration,change)airMoon(made of ether and it was a perfectSphere). Vertical movement aiming at the geometrical centre of the world was the natural movement

*A dualuniverseImmutable universe: beyond the moon (made of ether)

Change: only below the moonSimple versionAristotle: the universeEarthEtherSublunar spheres:The fourElements:(Earth, waterAir, fire)NB!The earth was the imperfect part of theuniverse,where constant change was taking place

That is why the perfect(equilibrium) distribution/layering of the four elemnts was not seen on earth

ComplicationsstarsEarth

*A dualuniverseImmutable universe: beyondthe moon

Change: only below the moonSimple versionCa 50 circles in total (some in opposite direction - in order to explain the retrograde movments of the planets!Aristotle: his complicated (real) universeEarthEtherSublunar spheres:Made of the fourelements EarthHeavenDual universe

**Retrograde movementsPlanet Mars Were explained in a (ad hoc) complicated way

*"Everything that is in motion must be moved by something", Physics (F = k x v)Aristotle on motion Fn = k x v Fn = k x a VS.AristotleNewtonAristotle on motion and why vacuum was impossible in nature:"As air resists motion, a body will either be left standing still when the air is removed because there is nothing to move against (! ?), or if it is put into motion, it must continue to move at the same speed forever. As this is absurd, no vacuum can exist " (Physics).

*Aristotle on free falls, and forced motionsImplications: the speed was infinite i vacuum (zero resistance) implyng vacuum was Impossible!! (The concept of infinity was not accepted, it was considered absurd)Speed = (Weigth/Resistance of the medium)Explanation for free fall:A stone falls to the ground (straight down) because this is its "natural habitat" and therefore it eagerly struggles to get there.

The heavier the stone, the higher the urge, the faster it would fall!

*Could not have vertical and horizontal motion at the same time!Aristotle on free falls, and forced motionsOnly one force acting at the same time (paradigm).

A forced force, would control the movment 100% until it was used up, then the stone would seek its natural place, the surface of the earth, though a vertical path.Drawing from ca. 1400 AD

*5th to 14th centuryGods perspective on the worldAugustine354-430Notice the absence of a depth perspectiveThe world must be drawn as God saw it, and He saw everything equally well !WHY?A paradigm.

*15th centuryIndividual perspective on the world Aquinas13th century- opened for the idea that an individual might recognise God's truthby studying nature as it was perceived personally, i.e. using Senses and Reason

Individualism!!Aquinas1225-12701413If one (you!9discovered laws of nature, one (you) found proof of God's orderA new paradigm.

*Aquinas ~ 1200 AD

Each person might make his or her own attempt to understand the laws, which meant that there was a culture encouraging the role of the individual. With Aquinas we see the dawn of individualism, a new phenomenon which came into full bloom in Galileo's time.

*Natural philosophy is viewed as the mother of all sciences

Without a developing natural philosophy, as seen during the late Middle Ages and with its broad (robust) metaphysical basis, it is not easy to see how modern science could have developed around 1600 and onwards. The culture became pregnant with the Scientific method in the late Middle Ages)

The important role of Natural philosophy

*The world as a machine

became a commonly used metaphor from 1200 AD and onwards.

A mechanical metaphor (only to be found in the western culture)A fruitful metaphore

- They came from (very) rich families

- They were men only

- They hired their own teachers

Sometimes they hired two teachers for the same course, and made them lecture at the same time (in two different rooms)!

The one that ended up having most students attending, was given a permanint position. The studentsin the Middle Ages:Universities in West (1200 AD

**A summary ..in light of the structure of and elements in a Scientific Theory(the next four ppts

**P1P2P3A1A2A3E1E2E3E4ExperienceThe pre-SorcateslogicThey questioned the basic assumptionsand suggested different basic elements, they did observe nature but did not perform experiments.

Also, their approach was qualitative, and not quantitative. They also proposed many different solutions to the same problem, but had no way to discriminate- other than between metaphycical preferences (and they were - and still are - private).

An

**P1P2P3A1A2A3E1E2E3E4ExperienceAristotles followers (late Middle Ages, ca 1200 - ca1600 AD)logicThey accepted the basic assumptions provided Aristotles

and were (like Aristotle) not concerned with experiments/observations, hence they were lost in a closed logical circle.

They proposed many differnet solutions to the same problem, but had not measure to discriminate between them except logical arguments.

Thought experiments (experiments without observations) where considered as real as we today look at experiments.

The value and the meaning of thought experiments were different from oursl

An

**Also their final conclusions had to comply with the Scripture, but they were in an aristotelian style (ref. his logic) - allowed to discuss other possible solutions in detail, hence they could as mentioned earlier - present their opinions and arguments freely and in full (like: that the earth circled the sun, that vacuum did not exsist) ans a mental exercise. Aristotles followers and the Church, ca 1200 - ca1600 AD)

**P1P2P3A1A2A3E1E2E3E4ExperienceScientific revolution.. embraced the whole iterative-circle!logicQuestions the basic assumptions!!- Observe nature, and performe experiments.

- The approach is quantitative. - Proposed many different solutions to the same problem, and had a way to discriminate between them (but not prove any of them!!).

The UniverseFrom Aristotle to Copernicus

**A dualuniverseImmutable universer: a beyond the moon

Change: only below the moonSimple versionCa 50 circles in total!Aristotle: his UniverseEarthEtherSublunar spheres:The fourelements EarthHeavenDual universeThe Island knowledge metaphorePlaton to Aristotle:Use circles and constant speedKeep it simple

**Retrograde movementsPlanet Mars Not so well explained by Aristotle

**Ptolemy(100-178)Ptolemey (Ptolemaios)Around ca. 1500) many different versions of the model were around, some with as much as 54 circles.+150+1500New ad hoc circles were added to get a more precise model(a 100% match was not required! - why?) more epicyclesarthA new inventionAd hoc solutions

**Ptolemy(100-178)The Middle AgeAround ca. 1500) many different versions of themodel were around, some with as much as 54 circles.+150+1500New ad hoc circles were added to get a more precise model(a 100% match was not required! - why?)

**Ad hoc solutionsMore epicycles (circles)

*From: A New Astronomy, Kepler, Chapter 1, (1609).

**

Comets+ new stars?(supernova)Aristotles model was challanged (immutable heaven?).Shining brightly a few weeks only (and then dissaperes)

*KometerComets

**The nature (origin/role) of the comets was not easy to understand.Earth

*Earth/stonewaterfireAristotles sublunar world (place for degeneration and change)airMoon Comets were fenomenataking place within the sublunar sphere.

It had to be so because the heaven was immutabelSolution:vAd-hoc assumption

**Before 1600 The eyes only,and mechanicalequipmentT. BraheThe neked eye paradigm

**The naked eye

**16701800A new paradigm

**1700

**Ptolemaios : the impossible implications of a roating earth the role of logic.FromAlmagestA rotating Earth wold have made it impossible for the birds to get back to their nests!

The earth rotets with a speed of ca. 2000km/hour

Copernicus1473-1543Copernicus..He made the Sun the centre of the Universe

Why did he do it?

How did he do it?

Was is simpler?

Did he have acess to new and better data?

**Copernicus addressed the problem based on mathematical objections to Ptolemaios model, and ended reluctantly with a solution that the earth (it followed from the assumptions) is a rotationplanet orbiting the sun.

The way he solved it

**With reference to Ptolemaios and Copernicus:The role of new data?You do not need new or better data to invent/construct a new theory!

Copernucus did not (!) have better data than Ptolemaios

**The system was built on aristotelian concepts of circles (around 50!). The planets travelled in crystalline shells (made of. ether!),

and he thought partly like Aristotlewhen it came to physics Simpler.?

**Copernicus made this figure in the introduction to his book, and this simplified picture of the model remains with many. Only a few read the whole book it was too complicated.

Galileo was one of those who obviously (?) had noticed the simplified model and this is what he defended (he was, however,probably aware of the more complex model)Copernicus' (simplified) modelThe Sun was not in the (true) geometrical centre in Copernicus modell.

*Copernicus true modelA nest of circlesimpossible to followand to draw, but here is a hint

**Retrograde movements in Copernicus modelElegantly explained by

**The retrograde movement of the planets were explained as due to relative movment. It was not real - as in the Ptolemaios earth centered model - but due to the perspective

**If the earth orbited the Sun, i.e. it moved, we would expect to observe the stars at different angels during a year.This was not observed, (they did not have good enough resolution)!, and this was an good argument used againsta sun centered universer

Arguments against a Sun-centered univers

**Why is there something instead of nothing? About realitySome questions are more fundamental than others.Leibniz.Leibniz1646-1716The answere is??. from nothing ?? because everything is (in sum total) nothing! (quantum physics opens for this)Or a modern question (The Big Bang): where does the energy come from?

**140016001800

Copernicus

BraheGalileoKeplerDescartesBoyle HuygensHookeLeibnizNewton

Bernoulli EulerLaplaceLinneLavoisier PriestleyDaltonrsted, Faraday,Ohm, Young,Fresnel

JouleMendelMendeleevMaxwellDarwinX-raysBequerellThomson PlanckM. CurieEinsteinRutherfordBohrSchrdingerHeisenberg

Ockham BuridianOresme,...Some of the most important natural scientists and their contributions(1300 to around 2000)Copernicusmade a system for celestial bodies with the sun in the centre.Inspired by previous ideas of the same.The first to make a mathematical model based on this idea.Seen as not harmful by the Catholic church.

New observations of planets(Brahe)Theory of motion(Galileo)Planets travelling in ellipses (Kepler)The modern coordinate system (Descartes)

Law of gases(Boyle). Newton's three laws of motionplusgravitation (Newton). Mathematics:dx/dy, ,(Newton/Leibniz).Light consists of particles (Newton).Light consists of waves Huygens)

Development of Newton's physics via dx/dy(Euler; Laplace, etc.)Biology is systematized (Linne) Modern chemistry (Lavoisier Priestley)

Modern atomic theory(Dalton)Law of electricity (Ohm). Relation between magnetism and electricity (rsted)Induction(Faraday)Light has wave nature(Young/Fresnel)

Law of heat(Joule), laws of inheritance(Mendel), periodicsystem(Mendeleev), Evolution of species (Darwin) Electro-dynamics(Maxwell)

X-rays(Rntgen),Electrons(Thomson) Radioactivity/splitting atoms (Becquerel, Curie), Energy is quantized (Planck)Photoelectric effect and theories of relativity(Einstein)Atoms have cores(Rutherford)Structure of atoms(Bohr)Quantum mechanicsSchrdinger/Heisenberg

Suggestion thatthe earth turned onits axis and around the sun.Modern ideas of motion. Attempts to link mathematics and physics (ina "primitive"coordinate system(Oresme)Extensive use of thought experiments, ie. experiemts without observations. 190015001700Super-stringtheory("unifiesevery-thing")

Human genomemapped

Read: to be discussedin this couseTo be read only

**1000-500The Roman Empire The Roman Empire was established in 510 BC, and was gradually divided into an eastern and a western part from the 400s. The western part collapsed just before AD 500. Augustine (around 400)Focus on spiritual matters. Knowledge about truth, i.e. God, through revelation. Attracted to Plato's theory of ideas (actually: Plotin: i.e. neo-Platonists ). One "must believe to understand"). One must also use one's reason (logical/analytical thinking) to understand God and seek true insight via the Bible. He nevertheless believed that those who wrote down the Bible may have misunderstood things (he discouraged literal interpretations of the Bible). God can never be fully understood, but one must do as much as one can. The material world was unimportant, being only a place where the body was due to original sin, hence one must seek to distance oneself from the sensible world to be saved (which Stoics also tried in their search for happiness in this life, on this earth).Aquinas (around 1250)God was a rational being. Hence the nature he had created was controlled by laws and could be understood through reason and senses. One was obliged to seek knowledge about God by trying to understand nature. Aquinas "Christened" Aristotle by unifying his philosophy with Christian teaching (Aristotle's writings were rediscovered through Arabic culture in the 13th c). Faith ranked above reason if there was a conflict between these approaches. ("The dark) Middle AgesThe Roman Empire collapsed, communications collapsed, cultural centres moved north to Germanic peoples. Church as an institution grew in importance due to the absence of a strong central power. The light was gradually turned on around 1000 ADPlato(Theory of ideas) The GreeksA culture that revolted against the mystical ideas about nature and applied reasonOn Western cultural ideas/thoughts to the development of the scientific method Modern science Discovery/invention of the scientific method formed the basis for explosive development of science,- and from around 1850 also of technology.Aristotle (Theory of matter)0Pre-Socratics(Rational world)1600Galileo (around 1600)Established (early attempts previously) a new and fertile way of studying nature by carrying out controlledexperiments, and by combining mathematics and physics. Boyle was the first to document whathe had done, thus enabling others to undertake independent assessment of the results. Together this became modernscience.

ArchimedesPab.19.08.2008To be read only

*Pre-sokratenePlatonAristotelesAugustin Aquinas4001200 16000Kopernikus Kepler, Galilei, Descartes, NewtonNy-platonisme Tales AnaximanderEmpedoklesHeraklit(es)Parmenides DemokritPyhtagoreerneetc.

aristotelismenArkimedes, Demokrit,Euklid, Platon andPhytagoreerne rediscovered To be looked atPtolemaios(Heliosentriske modell)-500

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