Introduction to courseA brief history of philosophy of science

Introduction: science, philosophy of science,and a brief history of philosophy of science

Christian Wthrich

http://philosophy.ucsd.edu/faculty/wuthrich/

145 Philosophy of Science

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

What is philosophy ofscience?

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

What is science and what distinguishes it from pseudoscience?

What is the scientific method, if there is any, and on what basiscan it claim to ensure the objectivity of scientific results?

How does science explain our observations and experiences?

Does scientific knowledge progressively grow in a linear fashionor is its evolution dominated by radical revolutions?

Are the scientists grounds for rejecting an old idea and forreplacing it with a novel theory completely rational and logicallyreconstructible or are they substantially influenced by irrationalfactors?

Do scientific theories give literally true accounts of the world as itis, or should we regard even the most elaborate andwell-confirmed theory merely as a useful tool to systematize ourexperience?

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Philosophy of Science

EpistemologyMetaphysics

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Relevance of philosophy of science

How does it happen that a properly endowed natural scientist comesto concern himself with epistemology?... Concepts that have provenuseful in ordering things easily achieve such an authority over us thatwe forget their earthly origins and accept them as unalterable givens.Thus they come to be stamped as necessities of thought, a priorigivens, etc. The path of scientific advance is often made impassablefor a long time through such errors. For that reason, it is by no meansan idle game if we become practiced in analyzing thelong-commonplace concepts and revealing those circumstancesupon which their justification and usefulness depend, how they havegrown up, individually, out of the givens of experience. By this means,their all-too-great authority will be broken.

Albert Einstein, Obituary for Ernst Mach (1916). Phys. Z. 17: 101f

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Einstein to Robert A. Thornton, 7 December 1944, EA 61-574

I fully agree with you about the significance and educational value ofmethodology as well as history and philosophy of science. So manypeople todayand even professional scientistsseem to me likesomebody who has seen thousands of trees but has never seen aforest. A knowledge of the historic and philosophical backgroundgives that kind of independence from prejudices of his generationfrom which most scientists are suffering. This independence createdby philosophical insight isin my opinionthe mark of distinctionbetween a mere artisan or specialist and a real seeker after truth.

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

A brief (and grossly incomplete) history ofphilosophy of science

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Ancient Greece and Aristotle (384-322 BCE)

first elements of inductive scientificmethodology in Greek AntiquityAristotle believed that to know athings nature is to know the reasonwhy it is and that we possessscientific knowledge of a thing onlywhen we know its causeidea of generalization from particularobservation to universal law of nature,and back from universal law toparticular predictioncontinuity of philosophical andscientific work

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Robert Grosseteste (1175-1253), Bishop of Lincoln

the real founder of the tradition ofscientific thought in medival Oxford(A C Crombie)first to fully grasp Aristotelianmethodology in Westexplained generalization fromobservation to law and back toprediction via notions of resolutionand compositionprinciples governing both paths mustbe verified by observation andexperimentation

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Roger Bacon (c. 1214-1294), Doctor mirabilis

delivered philosophical justification forexperimentation and observation(rather than reliance on authority) asthe source of true knowledge inscientific and theological matterspremises of experimental sciencesrequire verification by sciences moreperfect than themselves, i.e. bymathematicsIf in other sciences we should arriveat certainty without doubt and truthwithout error, it behooves us to placethe foundations of knowledge inmathematics. (Opus majus, I, Part IVOn Mathematical Science, 1268)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

There are two ways of acquiring knowledge, one through reason, theother by experiment. Argument reaches a conclusion and compels usto admit it, but it neither makes us certain nor so annihilates doubtthat the mind rests calm in the intuition of truth, unless it finds thiscertitude by way of experience. Thus many have arguments towardattainable facts, but because they have not experienced them, theyoverlook them and neither avoid a harmful nor follow a beneficialcourse. Even if a man that has never seen fire, proves by goodreasoning that fire burns, and devours and destroys things,nevertheless the mind of one hearing his arguments would never beconvinced, nor would he avoid fire until he puts his hand or somecombustible thing into it in order to prove by experiment what theargument taught. But after the fact of combustion is experienced, themind is satisfied and lies calm in the certainty of truth. Henceargument is not enough, but experience is. (Opus majus, II, Part VIOn Experimental Science, 1268)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Sir Francis Bacon (1561-1626), 1st Viscount St Alban

systematic establishment and popularizationof inductive methodology

Novum Organum, 1620

argued that reasoning from fact to axiom tolaw must be inductive, rather than deductive(as was the case in the Aristotelian tradition)

induction alone is insufficient, negativeinstances must be carefully examined (earlyprinciple of falsification)

reproducibility of scientific findings

natural laws, not mysterious substances orfinal causes, have explanatory power

human (and therefore scientific) knowledgeis cumulative; as contrasted by given a priori(in Scripture or Aristotelian texts)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Galileo Galilei (1564-1642)

concerned with the quantification ofexperimental resultsintroduced time as a physicalparameter to measure motionquantitativelyinsisted on the mathematical nature oflaws of nature

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Philosophy is written in this grand bookI mean theuniversewhich stands continually open to our gaze, but it cannot beunderstood unless one first learns to comprehend the language inwhich it is written. It is written in the language of mathematics, and itscharacters are triangles, circles, and other geometric figures, withoutwhich it is humanly impossible to understand a single word of it;without these, one is wandering about in a dark labyrinth. (IlSaggiatore (The Assayer), 1623)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Ren Descartes (1596-1650)

Discours de la mthode (1637): method of philo-sophical thinking is exhausted by four precepts(II.7-10):

1 never accept anything for true which cannotbe recognized clearly and distinctly so as toexclude all grounds of doubt

2 divide each of the difficulties underexamination into as many parts asnecessary

3 begin with objects the easiest to know,ascend by little and little to the more complex

4 always examine whether completeness andfull generality has been achieved

Meditationes de prima philosophia (1641): system-atic doubts concerning reliability of senses, cer-tainty in cogito, ergo sum

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Sir Isaac Newton (1643-1727)

issue of the proper role ofhypotheses in systematic enquiriesinto nature (also in Descartes andLeibniz)hypotheses non fingo (I feign nohypotheses, Principia, 1687)impropriety of introduction ofmetaphysical hypothesis in science(against Descartes and Leibniz)but: needs hypotheses himself...

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

I have not been able to discover the cause of those properties ofgravity from phenomena, and I frame no hypotheses; for whatever isnot deduced from the phenomena is to be called a hypothesis, andhypotheses, whether metaphysical or physical, whether of occultqualities or mechanical, have no place in experimental philosophy.

(Letter to Robert Hooke, 1676, and almost verbatim in Principia)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

David Hume (1711-1776)

one of most outspoken and sublestdefender of empiricism (combinedwith scepticism and naturalism)problem of induction: the reliability ofan inductive inference from pastexperience to prediction concerningfuture must be underwritten by aprinciple of inductionbut such a principle cannot claimlogical necessity; nor can it be basedon the past success of induction onpain of circularitynevertheless: induction is necessarytool for empirical sciences

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Custom... is the great guide of human life. It is that principle alonewhich renders our experience useful to us, and makes us expect, forthe future, a similar train of events with those which have appeared inthe past. Without the influence of custom, we should be entirelyignorant of every matter of fact beyond what is immediately present tothe memory and senses. We should never know how to adjust meansto ends, or to employ our natural powers in the production of anyeffect. There would be an end at once of all action, as well as of thechief part of speculation.

(An Enquiry Concerning Human Understanding V, Part I, 1748)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Immanuel Kant (1724-1804)

rational human agent at center ofcognitive activity

synthesis of rationalist and empiricistpositions

rational order of world cannot simply beaccounted for by sense perceptions

conceptual unification and integration byactive mind using precepts (space, time)and following categories ofunderstanding (cause, substance)operating on manifold of senseperceptions

consequently, objective causal structure ofworld depend upon mind

mind makes ineliminable constitutivecontribution to knowledge

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

There can be no doubt that all our knowledge begins withexperience. (B 1)... Thoughts without content are empty, intuitionswithout concepts are blind. (B 75) [Sometimes paraphrased asConcepts without percepts are empty, percepts without concepts areblind.]... Thus all human knowledge begins with intuitions, proceedsfrom thence to concepts, and ends with ideas. (B 730)

(Critique of Pure Reason, 1781/87)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Bernard Bolzano (1781-1848)

Theory of Science (1837)attempted to provide logicalfoundations of science, building onabstractions like part-relation, abstractobjects, attributes, sentence-shapes,ideas-as-such, propositions, sumsand sets, and sentence-occurrencesthese abstractions existindependently of our mindslogical consequence is not identicalwith explanation

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Auguste Comte (1798-1857), positivism

Cours de philosophie positive(1830-1842)only scientific knowledge is authenticknowledgestrict application of scientific method,completely barring any metaphysics(and any theology)circular dependence of theory andobservationknowledge possible of facts, ratherthan of causesfounder of sociology: applied scientificmethods to social world

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

William Whewell (1794-1866)

The Philosophy of the Inductive Sciences,Founded Upon Their History (1840/47)

knowledge involves both ideal andempirical elements, fundamental ideas(space, time, cause) necessary

i.e. observation is idea-laden, involvesunconscious inference

renovated F. Bacons notion of induction

induction more than enumeration andextending to unobserved instances

generalization in induction requireselement of colligation, i.e. the mental actof bringing together empirical facts in waythat renders them capable of beingexpressed by a general law (pearls andstring)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Whewell: Novum Organon Renovatum (1858)

Confirmation of hypothesis discovered via induction occurs by:

1 prediction: our hypotheses ought to fortel [sic] phenomenawhich have not yet been observed (p. 86)

2 consilience: explain and determine cases of a kinddifferent from those which were contemplated in theformation of those hypotheses (p. 88)

3 coherence: hypotheses must become more coherentover time (p. 91)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

John Stuart Mill (1806-1873)

A System of Logic (1843)Mills notion of induction does notinvolve mental acts such ascolligationfive principles of induction: themethod of agreement, the method ofdifference, the joint or double methodof agreement and difference, themethod of residues, and the methodof concomitant variationsto explain a fact is to locate a lawunder which it can be subsumed:covering-law model of explanation

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Mill: A System of Logic (1843)

Method of difference:

If an instance in which the phenomenon under investigationoccurs, and an instance in which it does not occur, have everycircumstance in common save one, that one occurring only inthe former: the circumstance in which alone the two instancesdiffer, is the effect, or cause, or a necessary part of the cause,of the phenomenon.

(A System of Logic III, Ch. viii, 2)

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Ernst Mach (1838-1916)

methodological economy of thought:scientific laws are mere summaries ofexperimental events, constructed forthe purpose of human comprehensionthus, laws are essentially mentalconstructionsempiricism: knowledge of the naturalworld must be grounded in experience(directly via sense impressions or viameasurement results)uncompromising reductionismdiscussions on the reality of scientifictheories are completely superfluous,only their utility counts

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Positivism according to Mach

1 The source of human knowledge is the given.2 Only a manifold of sense impressions is given.3 Whatever constitutes the world over and above the

contents of sense preceptions is not given.4 The distinction between the I and the world is untenable.5 There is no metaphysical knowledge about an

extra-perceptual reality.

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Charles Peirce (1839-1914)

sign-theoretic or semiotic theory ofinferenceexamined three fundmental modes ofinference: abduction, deduction andinductionabduction ( inference to the bestexplanation), is used to generate alikely hypothesis in response tophenomenon under scrutinypragmatic considerations, i.e.considerations on the practicalconsequences, significantly enter theabductive work

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Henri Poincar (1854-1912), conventionalism

La science et lhypothse (1902),Science et mthode (1908)conventionalism: laws and theoremsrelevantly rest upon conventionsgeometry of physical space isconventional: either one stipulatesproperties of measuring devices anddetermines the geometry of space, orone stipulates a geometry of spaceand infers geometrical properties ofphysical bodies such as measuringdevicesbut conventions are not arbitrary, theyare constrained e.g. by rules whichmust be followed in negotiating them

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Pierre Duhem (1861-1916), holism

La thorie physique son objet et sastructure (1906)we can never test an individualscientific hypothesis, but always andby necessity must test an entiretheoretical groupreason for this: cannot dispense withauxiliary hypothesis (concerning e.g.measuring apparatus) in deducing anobservation sentence

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of science

Ancient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s

Ludwik Fleck (1896-1961)

Entstehung und Entwicklung einerwissenschaftlichen Tatsache (1935)

scientist are enclosed in their and theircommunitys preconceptions, and styles ofthinking

these styles have grown historically andare ineliminably social, i.e. a culturalproduct of a community at a certain placeat a certain time

development of science is notunidirectional, but its dynamics isdetermined by the cultural dynamics in thescientific communities

progress is not cumulative

truth is unattainable in scientific enquiry

Christian Wthrich Topic 1

Introduction to courseA brief history of philosophy of scienceAncient and MedivalScientific RevolutionEighteenth and Nineteenth CenturiesTurn of the century until the 1930s