Philosophy of Philosophy of ScienceScience

‘‘‘‘Science’’ in a Science’’ in a philosophical contextphilosophical context

NOT these!NOT these!

Rather… A particular attitude Rather… A particular attitude and method of argumentationand method of argumentation

1.1. ObservationObservation2.2. HypothesisHypothesis3.3. ExperimentationExperimentation4.4. ConclusionConclusion

THE SCIENTIFIC METHOD

So what are arguments?So what are arguments?

A main point (A main point (conclusionconclusion))

Together with reasons (Together with reasons (premissespremisses) ) that are that are supposedsupposed to provide evidence to provide evidence that the conclusion is correctthat the conclusion is correct

An An exampleexample

Main point (conclusion) Main point (conclusion) - I have fantastic socks - I have fantastic socks

Reasons (premisses)Reasons (premisses)- Qood quality- Qood quality- Durable- Durable- They’re colourful! - They’re colourful!

In formal notationIn formal notationP1P1) My socks are of a good quality.) My socks are of a good quality.P2P2) My socks are durable.) My socks are durable.P3P3) My socks are colourful.) My socks are colourful.CC) My socks are fantastic.) My socks are fantastic.

1.1. DEDUCTIVE / VALIDDEDUCTIVE / VALID - Start with a law, and work down to individual - Start with a law, and work down to individual

examples. examples. IFIF the premisses are true, then the the premisses are true, then the conclusion is conclusion is DEFINITELYDEFINITELY true. true.

Example:Example:

P1) All bachelors are unmarried males.P1) All bachelors are unmarried males.P2) Beethoven was an unmarried male.P2) Beethoven was an unmarried male.

C) Beethoven was a bachelor.C) Beethoven was a bachelor.

Types of arguments and Types of arguments and conclusionsconclusions

Advantages + DrawbacksAdvantages + Drawbacks Deductive arguments are Deductive arguments are not ampliativenot ampliative. In other . In other

words, the conclusion merely restates what is words, the conclusion merely restates what is already implicit in the premisses---we learn nothing already implicit in the premisses---we learn nothing newnew. This can be . This can be revealingrevealing, if nothing else. Consider , if nothing else. Consider this:this:

P1) You ride the train to and from work 2 hours per P1) You ride the train to and from work 2 hours per day, 5 days per day, 5 days per

week, 49 weeks per year.week, 49 weeks per year.

C) You spend 490 hours per year (almost 3 full weeks) C) You spend 490 hours per year (almost 3 full weeks) riding the train to and from work (ouch!).riding the train to and from work (ouch!).

Deductive arguments however are valid. Deductive arguments however are valid. This means that IF the premisses are true, This means that IF the premisses are true, then the conclusion MUST be true. This is then the conclusion MUST be true. This is a very powerful trait of deductive a very powerful trait of deductive arguments because one cannot argue with arguments because one cannot argue with the conclusion provided the premisses are the conclusion provided the premisses are true. IF Beethoven was an unmarried male, true. IF Beethoven was an unmarried male, and IF all unmarried males are bachelors, and IF all unmarried males are bachelors, then nobody can argue with the conclusion then nobody can argue with the conclusion that Beethoven was a bachelor (they may that Beethoven was a bachelor (they may however wish to challenge the premisses).however wish to challenge the premisses).

2.2. INDUCTIVE / INVALIDINDUCTIVE / INVALID- Start with an individual observation (or group - Start with an individual observation (or group of observations) of observations) and then work upward to form work upward to form a general law. a general law. IF IF the premisses are true, then premisses are true, then conclusion is conclusion is PROBABLYPROBABLY true. true.

Example = Example = P1) Many philosophy teachers use slides to teach.P1) Many philosophy teachers use slides to teach.P2) Rob is a philosophy teacher.P2) Rob is a philosophy teacher.

C) Rob uses slides to teach.C) Rob uses slides to teach.

Advantages + DrawbacksAdvantages + Drawbacks Inductive arguments are ampliative. Inductive arguments are ampliative.

They can tell us something new that They can tell us something new that is not implicit in the premisses (such is not implicit in the premisses (such as Rob’s teaching methods).as Rob’s teaching methods).

The biggest problem is that the truth The biggest problem is that the truth of the premisses do not always of the premisses do not always guarantee the truth of the conclusion.guarantee the truth of the conclusion.

The Problem of The Problem of InductionInduction

Just because the premisses are true, Just because the premisses are true, that does not mean the conclusion that does not mean the conclusion will be true. In other words, just will be true. In other words, just because you observe that SOME Xs because you observe that SOME Xs are Ys, that does not mean that ALL are Ys, that does not mean that ALL Xs are Ys! We can never be 100% Xs are Ys! We can never be 100% sure that the future will resemble sure that the future will resemble the past.the past.

Consider this:Consider this:According to James Ladyman, the According to James Ladyman, the principle of inductionprinciple of induction is this:is this:

‘‘‘‘When a large number of observations of Xs under a wide When a large number of observations of Xs under a wide variety of conditions have been made, and when all Xs variety of conditions have been made, and when all Xs have been found to possess property Y, and when no have been found to possess property Y, and when no instance has been found to contradict the universal instance has been found to contradict the universal generalisation ‘All Xs possess property Y,’ then one may generalisation ‘All Xs possess property Y,’ then one may legitimately infer a universal generalisation from a legitimately infer a universal generalisation from a

collection of collection of observation statements. ’’observation statements. ’’ - - Understanding Philosophy of Understanding Philosophy of

ScienceScience, pp. 28---9., pp. 28---9.

So let’s construct an So let’s construct an argument…argument…

P1) We have made a large number of observations of swans P1) We have made a large number of observations of swans under a under a

wide variety of conditions.wide variety of conditions.

P2) All swans have been found to possess the property of P2) All swans have been found to possess the property of being being

white.white.

P3) No instance has been found to contradict the universal P3) No instance has been found to contradict the universal generalisation ‘All swans possess the property of being white.’generalisation ‘All swans possess the property of being white.’

C) All swans are white.C) All swans are white.

But all swans aren’t But all swans aren’t white!white!

FalsificationFalsificationismism

Karl Popper’s (Viennese Karl Popper’s (Viennese Philosopher, 1902 – 1994) solution Philosopher, 1902 – 1994) solution to the problem of inductionto the problem of induction

Not really a ‘solution,’ but a way to Not really a ‘solution,’ but a way to avoid the problem altogetheravoid the problem altogether

So what do we do?So what do we do?

Instead of trying to gather a Instead of trying to gather a lot of lot of evidenceevidence to to proveprove a theory, just try to a theory, just try to obtain obtain one single pieceone single piece of evidence of evidence that that falsifiesfalsifies it (e.g. a black swan). it (e.g. a black swan).

Consider the following:Consider the following:P1) We have observed that most swans are P1) We have observed that most swans are

whitewhiteunder a variety of conditions.under a variety of conditions.C) All swans are whiteC) All swans are white

NO. 1:

P1) We have observed a single instance of a non-white swan.

C) It is not the case that all swans are white.

NO. 2:

Notice that NO. 2 is deductive in nature, Notice that NO. 2 is deductive in nature, meaning that meaning that IFIF the premisses are true, the premisses are true, then the conclusion then the conclusion MUSTMUST also be true. also be true. According to Popper, we are wasting our According to Popper, we are wasting our time trying to gather ‘enough’ evidence time trying to gather ‘enough’ evidence to ‘prove’ a theory beyond all doubt to ‘prove’ a theory beyond all doubt (because it’s impossible), but we can (because it’s impossible), but we can easily acquire enough evidence to easily acquire enough evidence to disprovedisprove a theory because all it takes is a a theory because all it takes is a single contradictory observationsingle contradictory observation..

So…So… When doing science (i.e. when ‘being When doing science (i.e. when ‘being

scientific’ and analysing arguments in an scientific’ and analysing arguments in an everyday setting) we should treat the word everyday setting) we should treat the word ‘proof’ with a healthy dose of suspicion! ‘proof’ with a healthy dose of suspicion! If the If the premisses don’t support the conclusion, premisses don’t support the conclusion, then it’s a bad argument.then it’s a bad argument.

Inductive conclusions are very valuable, but Inductive conclusions are very valuable, but there is nothing to guarantee that they are there is nothing to guarantee that they are true---only the assumption that the future will true---only the assumption that the future will mirror the past.mirror the past.

A revisit…A revisit… When faced with adverts like this, what When faced with adverts like this, what

they really they really shouldshould say is: say is:

The Cholestin Breakthrough! We have The Cholestin Breakthrough! We have made a large number of observations of made a large number of observations of our product being tested under a wide our product being tested under a wide variety of conditions and people! In all variety of conditions and people! In all instances, it has possessed the property instances, it has possessed the property of lowering the cholesterol of the test of lowering the cholesterol of the test subjects! No instance has been found to subjects! No instance has been found to contradict the universal generalisation contradict the universal generalisation ‘The Cholestin Breakthrough possess the ‘The Cholestin Breakthrough possess the property of always lowering the property of always lowering the cholesterol of the test subjects!’ We then cholesterol of the test subjects!’ We then legitimately infer the universal legitimately infer the universal generalisation ‘The Cholestin generalisation ‘The Cholestin Breakthrough always lowers the Breakthrough always lowers the cholesterol of those who subscribe to it’ cholesterol of those who subscribe to it’ from the collection of these observation from the collection of these observation statements! statements!

All it would take is a single contradictory observation All it would take is a single contradictory observation (i.e. a test subject whose cholesterol level rises) in (i.e. a test subject whose cholesterol level rises) in order to falsify the conclusion.order to falsify the conclusion.

The ‘more’ falsifiable a hypothesis is, the better. If it’s The ‘more’ falsifiable a hypothesis is, the better. If it’s very falsifiable (i.e. if there are many things that very falsifiable (i.e. if there are many things that couldcould falsify it, but don’t, then that means the theory is falsify it, but don’t, then that means the theory is stronger because it has withstood more sceptical stronger because it has withstood more sceptical attacks (e.g. ‘attacks (e.g. ‘coppercopper expands when heated’ VS ‘ expands when heated’ VS ‘all all materialsmaterials expand when heated’). Conversely, expand when heated’). Conversely, hypotheses that are unfalsifiable are simply bad hypotheses that are unfalsifiable are simply bad hypotheses and should be excluded from science. hypotheses and should be excluded from science. Many would include astrology and creation ‘science’ Many would include astrology and creation ‘science’ in this category.in this category.

There will be a little more about falsifiability and There will be a little more about falsifiability and deduction next week!deduction next week!

Suggested Suggested ReadingReading

Ladyman, James (2002). Ladyman, James (2002). Understanding Philosophy Understanding Philosophy

of Scienceof Science. . RoutledgeRoutledge..