1. Sources of Knowledge: The origin of concepts and the nature of knowledge
Outcomes:
to understand the key claims made by the different schools of epistemology about the sources of knowledge
to have begun considering how the validity of these claims
Warm-up:
List five things you know
How do you know these things? What is the source of this knowledge?
Is there anything in common between these sources? Are there any ultimate sources of knowledge

3. Empiricism Works with the evidence of the senses.
Ultimate source of knowledge is sense experience.

4. Gnosticism: Works with evidence provided by God
Ultimate source of knowledge is divine revelation

5. Rationalism:
Works with evidence provided by rational thought – logic alone
Ultimate source of knowledge is reason

6. Empiricism
the information our senses give us is the ultimate source of all knowledge – reason works with this data.
Rationalism
- reason alone is the ultimate basis of all knowledge – sense-data only extends what we already know.

7. Socrates (469-399 BCE) & pupil & amanuensis Plato (428-348 BCE)
Descartes ( )
Rationalism
Gottfried von Leibniz ( )
Spinoza (1632–1677)

8. Empiricism Aristotle (384-322 BCE), pupil of Plato
John Locke (1632 –1704 )
Empiricism
Bertrand Russell (
David Hume ( )
George Berkeley (1685–1753 )

9. Rationalism & Empiricism
Immanuel Kant ( )

10. Different meanings of ‘idea’:
a PROPOSITION: e.g. ‘He had the idea it would be fun to take a day off’
Or:
or CONCEPT: e.g. ‘yellow’

11. Innate ideas:
Definition 1 (Locke): An idea which is a proposition or concept which is part of the mind at birth (and we are conscious of it).
Definition 2 (Rationalist): An idea which gives us substantive a priori knowledge through rational intuition and demonstration.
Definition 3 (Nativist): An idea which is a proposition or concept, with which the subject has been born, rather than gaining it from experience.

12. John Locke:
We are born without any ideas – our mind is a ‘blank slate’ (a tabula rasa) (Locke extract: p.106, sheet)
What reasons are there for agreeing with Locke?
ACTIVITY, p.108
Do concepts such as a ‘human being’ come ready-formed? What are the simplest concepts possible?

13. Locke’s theory of concept formation:
What sense impressions go towards making up your idea of a human being?
Simple Impressions – flesh tones in different shapes, eye colours in eye shapes, shape of hair in a colour, etc.
Complex impressions of a human being
Complex Ideas – of a human being
We must first acquire sense impressions to form concepts, and concepts to be able to think of propositions – e.g. ‘The cat sat on a mat’

14. Locke’s theory:
See diagram on page 108! Copy, replacing the examples with ones of your own.
Why do we need ‘concepts’ (ideas) as well as sense data?
How can we come up with or imagine ideas of things we’ve not experienced?
Are there any ideas you can think of which don’t come from sense-experience?

15. Both Locke and later David Hume argue that we develop concepts of which we do not have sense impressions by working with sense impressions and concepts we already have. (Hume extract, p.107)
Hume argues that the following are operations which are used in forming complex ideas, including those of which we have had no experience:
Augmentation - enlarging
Diminishment - reducing in size
Compounding - bringing two entire things together
Transposing - taking an element from one thing and putting it together with another
Negating- excluding an element of something
Give an example of an idea of fantasy which these operations could produce.
- Activity, p.110 – do Locke and Hume’s theory work for all our ideas?

16. Locke’s supporting arguments:
Nothing is thought universally – therefore it seems unlikely that we are born with innate concepts
Children and ‘idiots’ (Locke’s term) do not have complex concepts (e.g. mathematical) that are claimed to be innate by Rationalists.
Empiricism is the simplest explanation of our ideas.
Hume’s supporting arguments:
A blind woman cannot have a concept of colour.
A mild man cannot have a concept of white-hot anger.
We cannot have ideas of something we have not (directly or indirectly) experienced.

17. Hume on knowledge: A wise man proportions his belief to the evidence.
David Hume (An Enquiry Concerning Human Understanding, 1748)
Belief is nothing but a more vivid, lively, forcible, firm, steady conception of an object, than what the imagination alone is ever able to attain.
David Hume

18. Hume’s scepticism:
- To know whether an idea is a genuine concept or not, we must trace back its genesis to the original sense impressions which have created it.
- IF we cannot find such impressions, then the idea must be false – we have made an error in supposing it to exist.
We might, though, be able to trace an idea back to its constituent parts, and see why we have created the concept.
Can you think of any philosophically-significant concepts which we might have created through the operations that Hume describes?

19. Hume’s view of metaphysics:
Abstract ideas are characteristically vague and faint;
Abstract ideas need to be reduced to their constituent sense impressions to see if they are accurate;
Without reference to experience, words/concepts are nonsense, because they signify no idea;
Ideas that speculate about a reality beyond or behind our experience are ‘merely sophistry and illusion’

20. Metaphysics:
“If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, "Does it contain any abstract reasoning concerning quantity or number?" No. "Does it contain any experimental reasoning concerning matter of fact and existence?" No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.”
- Hume, Enquiry Concerning Human Understanding

21. What would Hume’s view of the following be?
The idea that there is a God who is infinite, all-loving, all-powerful, etc.
The idea that we exist through time as a ‘thinking thing’? (Descartes)
The idea that certain ideas are necessarily true? And that certain things MUST happen? (e.g. the sun rising tomorrow)
The idea that we can identify a priori the relationship between an event and its cause? (i.e. one thing definitely being the cause of another)

22. Identity and Selfhood:
“What we call a mind is nothing but a heap or collection of different perceptions, united together by certain relations and supposed, though falsely, to be endowed with a perfect simplicity and identity.”
David Hume (A Treatise of Human Nature, )

23. Necessity and Causation:
“Upon the whole, necessity is something, that exists in the mind, not in objects; nor is it possible for us ever to form the most distant idea of it, consider'd as a quality in bodies. Either we have no idea of necessity, or necessity is nothing but that determination of thought to pass from cause to effects and effects to causes, according to their experienc'd union.”
David Hume (A Treatise of Human Nature, )

24. Necessity and Causation:
“That the sun will not rise tomorrow is no less intelligible a proposition, and implies no more contradiction, than the affirmation, that it will rise.”
David Hume (An Enquiry Concerning Human Understanding, 1748)

25. Introducing Hume…
- scepticism
– Hume’s Fork

26. Logical Positivism:
20th century philosophical movement inspired by Hume’s empiricism
Claimed that sentences are only meaningful (provide us with information) if they are susceptible to empirical proof, or can be logically proven.
What kind of statements would this view rule out as ‘meaningful’? (Think of the other side of your course!)

27. Criticisms of Hume:
Departs too far from common sense, e.g. in arguing that the self does not exist - do we simply have to accept the self?
Just what counts as a ‘simple’ idea? (p.115)
Can Hume’s theory of complex ideas account for abstract nouns such as beauty, truth, knowledge?
- Can you find a concept which doesn’t seem to derive from experiences?
How could we imagine ideas – e.g. a previously unexperienced shade of blue – if Hume’s theory is correct?

28. What counts as a ‘simple’ idea?
Unicorn = horse, horn
What constitutes a horse? A horn?
What constitutes a mane, hide, tail, etc.?
What constitutes hair?
Etc……

29. Criticism 2: Do all simple ideas come from sense experience?
Hume asks us to imagine whether someone who has never seen a particular shade of blue could imagine such a shade.
Hume thinks it is plausible that they could. Does this undermine the Empiricist case?

30. Missing shade of blue… The ‘missing shade’ could be a complex concept.
But then… all shades of blue would be complex shades – mixtures of light and dark with general concept.
How then is any shade derived from a simple concept?
How do we move from any particular shade of blue to the general concept? And back?!

31. Missing shade of blue…
But if we cannot form the missing shade, then we must have millions of different concepts of every colour.
Do we all have slightly different conceptions of blue, according to our experiences?
If I have not experienced a shade, then it is not part of my general concept of blue. But how then do I recognize a new shade as blue?
What about ultra-violet – we can form a concept of it, but this is not derived from sense experience.

32. Criticism 3: Concepts which don’t relate to sense impressions:
What sense impression is the concept of Spain based on?
What sense impression is the concept of justice based on?
What sense impression are the concepts of prepositions (e.g. being near/far/next to/on top of, etc.), or relations (e.g. sibling) based on?
Do such concepts need to be rooted in ‘pictures’ at all? Are they more issues of logic, or innate ideas about relationships?

33. Abstract concepts:
How do we account for the connections between concepts involved in, for example, justice?
How can we arrive at similar concepts despite very different experiences?
Relational concepts – e.g. ‘on’, ‘between’, ‘and’, ‘sibling’, etc.

34. Criticism 4:
Do some concepts have to exist in the mind before sense impressions can be properly experienced?

35. Condillac’s Statue P
Would not a statue, which had a blank slate for a mind, and which received all its information from external sources, only forming ideas from this, not be faced with a ‘blooming, buzzing confusion’ of sense data (William James), without some innate categories which enable us to process it all?
Modern analogy: a computer without software?
Kant on the tabula rasa: “Thoughts without content are empty; intuitions [impressions] without concepts are blind.”
Are there innate structures, or ideas, which guide our understanding of sense experience?

36. Rationalist criticisms:
Are innate ideas those ideas which come to us only when we have full use of reason? (not children, mentally disabled)
Could we have a disposition implanted by God to think in way which leads to a priori truths
Descartes: a priori reasoning, self-reflection, rational intuition.
Plat’s innatism: ‘remembering’ specific concepts

37. Rationalist criticisms:
Could experience trigger innate knowledge? (either DISPOSITIONAL (Descartes) or INNATIST (Plato)). Just as we have innate capacities which develop, why not also innate concepts and knowledge which also develop (could be genetically encoded - Carruthers)?
Leibniz: we are like a marble block which has ‘veins’ which guide the impressions a sculptor can make
Carruthers and Chomsky: language-use (p.123)
- how can Chomsky’s theory be criticised?

38. Empiricist’s response:
A baby’s ‘knowing’ that it should suckle is simply know-how, not propositional knowledge – it doesn’t know anything about the objects it is trying to manipulate, but how to use them.

39. Homework:
Outline and explain the criticisms of Empiricist theories of concept acquisition. (9 marks)

40. Keywords: Ideas: mental experiences (e.g., concept of ‘yellow’)
Concept: an abstract representation of something – either of a particular thing, or of a relation between things
Knowledge: a proposition about something (e.g. this screen is black, blue and white in colour)
A priori: knowledge known independently from experience (e.g. no object can be red and green all over at the same time)
A posteriori: knowledge known through experience – i.e. learned.
Deductive argument: an argument in which the truth of the premises will guarantee a true conclusion.

41. Innate ideas Claim that some of our ideas are not learned, but innate
All our (propositional) knowledge is rooted in the logical relations between these ideas – i.e. in reason and how these ideas are applied to our sense experience
Different versions of the claim: e.g. ideas could be implanted by God, be memories from a different life, emerge from the way our minds work, be part of the way our brain has evolved.

42. Descartes:
Why does Descartes think that our knowledge must be rooted in ideas provided by reason alone, not by experience?
(Reading, p.373)

43. Descartes’ innate ideas:
What does Descartes think he can know for certain?
What arguments does Descartes use to prove that God exists?

44. Criticisms of Trademark Argument:
1) Does every event have an equal cause?
Evolution
Match lighting a bonfire
Whisper setting off an avalanche
2) Do we really have an idea of infinity? And if not, does this mean that Descartes’ trademark argument cannot get off the ground?

45. Criticisms of Trademark Argument (2):
3) The idea of God is incoherent:
Paradox of the Stone
If incoherent, what does this imply about its cause?
4) Idea of an all-powerful God is not universal:
- Omnipotent deity emerges at a historical point

46. Descartes’ ‘trademark’ argument for God – criticisms, cont.:
5) Empiricist accounts of origin of idea of God:
- Our idea of God isn’t innate (and certainly not simply produced by something as powerful as God), but a sum of our experiences and our ability to think of them negatively (e.g. not finite = infinite) (Hume!)

47. Descartes’ ‘clear and distinct ideas’ about external world:
Descartes’ example: wax
Intuited by the mind, by ‘light of reason’
Known by reason alone, therefore objective (available to all) – ‘primary qualities’
E.g. basic claims of logic, geometry, mathematics
Cannot be doubted – all self-evident
Qualities such as smell, colour, feel, etc. are subjective (dependent on the observer) – ‘secondary qualities’

48. Other arguments for innate ideas:
(Note distinction between innate instinct – know-how - and innate idea/concept – knowing that)
Morality – God-given? Intuitive? Rational?
Numbers – mathematical relationships
Beauty, justice, universal concepts

49. Chomsky on language
Modern philosophers have recognised the power of language to form the world we experience.
Noam Chomsky claims that we have ‘rules’ for language-use ‘hard-wired’ into our minds – a version of the thesis of innate ideas.

50. Criticisms of innate ideas:
Locke:
1) Theory of innate ideas is unnecessary – empiricism can explain where all our ideas come from (employs Occam’s Razor) (p.137)
E.g. why would God provide us with eyes to see colour if we already had an innate idea of it?
- However, does this account for all possible ‘innate’ ideas?
2) No ideas are universally held, therefore none is innate.
activity, p139
E.g. Children and the mentally impaired do not have knowledge of even logically necessary truths.
However, does this necessarily negate possibility of innate ideas?

51. Rationalist responses:
Could some people not be aware of the innate ideas in their minds, or that their minds have the potential to think? Are some people simply incapable of articulating these ideas? (Leibniz)
Do all innate ideas have to be universal? Or vice versa?
- Could be that only some people have innate ideas

52. 3) Transparency of ideas:
Locke claims that the claim that some people might not be aware of innate ideas doesn’t make sense – see quote, 141.
To be an idea, must have been thought (‘perceived’).
However, does this ignore the role of the unconscious, or subconscious? Or ideas that become perceived when we are stimulated in some specific way? (c.f. Chomsky’s argument about language acquisition)

53. 4) How can we distinguish innate ideas from other ideas?
Locke rejects ‘capacity’ criticism: if we can have innate capacities for some ideas, why not for all ideas (sense experiences as well as logic)? How can we tell the difference?
However, Leibniz argues that ideas which are innate (even in potential form) are necessarily true (‘necessary truths or ‘truths of reason’), whilst ideas from sense impressions are ‘truths of fact’, and contingent. E.g. Socrates teaching the slave boy in the Meno.

54. 5) Reliance on the supernatural:
Many forms of innatism claim that God is responsible for putting innate ideas in our minds. If we reject belief in God, we undermine these grounds.
However, not all forms of innatism rely on supernatural. Cf. Chomsky’s theory, processes of evolution ‘hard-wiring’ certain ways of understanding the world into our brains (‘nativism’)

55. Summary of concept empiricism:
Key claim: all our ideas and concepts must be derived from our impressions.
Criticizes claims of innatism (rationalism)
Critiqued in turn for assuming what must already be in the brain before we begin to experience.

56. Questions for Rationalism:
are physical laws a priori, or are they empirical?
could they have been different?
Even if Descartes is right about a priori knowledge, does it tell us much about the world at all?
Which of the following statements can be known a priori (before testing through experience)?
Parallel lines can never meet
All sounds have a pitch
All swans are white
Every event has a cause
People need water to live
Space has three dimensions
2 is to 4 as 4 is to 8

57. Knowledge Empiricism:
Concepts are the basis of knowledge – what we think we know about the world
Activity, p.144
Foundationalism: the claim that concepts from a particular source provide a firm basis for knowing something

58. Empiricist Foundationalism
The claim that our sense data provides something that we are certain of
i.e. we cannot doubt that we have certain sense data.
Locke thinks this can provide us with a ‘foundation’ for gaining knowledge of the world itself.
i.e. we gather sense-data, from which we infer the existence of a world, and make generalizations which help us predict how that world behaves.

59. The sceptical challenge: ‘Brain in a vat’ thought-experiment (updating of Descartes!)

60. The sceptical challenge:
Descartes’ thought-experiment puts in question what can we know about the world for certain from sense impressions.
Hume acknowledges the challenge of Descartes’ thought-experiment, and argues that whilst we can know we have certain sense data, and that rules of logic are true, we can’t know anything for certain about the world!

61. Logical conclusion of Empiricism:

62. Hume quotation, p.150
See box, page 151, for Hume’s division of ‘types’ of knowledge.

63. Hume’s Fork: terms to use:
Some of these have been muddled up – which?
Relations of Ideas
A posteriori
Inductive
Analytic
Tautologies
‘Belief’
Matters of Fact
- A priori
Deductive
Synthetic
Claims about the world
- ‘Certain Knowledge’
See pp.151 and 155 boxes!

64. Hume’s Fork: terms to use:
Analytic
A posteriori
Deductive
Tautologies
Matters of Fact
A priori
Synthetic
Knowledge
Belief
Matters of Fact
Inductive
Relations of Ideas

65. Hume:
“When we go through libraries, convinced of these principles, what havoc must we make? If we take in our hand any volume – of divinity or school metaphysics, for instance – let us ask, does it contain any abstract reasoning about quantity or number? No. Does it contain any experiential reasoning about matters of fact and existence? No. Then throw it in the fire, for it can contain nothing but sophistry and illusion.”

66. Explain Hume’s ‘fork’ (9)

67. Different types of knowledge:
Proposition = a claim about something
There are different types of proposition:
See box, p.155 for crucial distinctions!
ANALYTIC - e.g. ‘squares have four sides’
= the ‘predicate’ – description (‘four sides’) - is already contained in subject’s definition (squares are four-sided shapes)
= true by virtue of logic alone. Tautologous – no new information in predicate, and no new information about anything in reality itself.
= can be known a priori
SYNTHETIC – e.g. ‘London buses are red’
= predicate (red) not part of the definition of the subject (London buses)
= only true by virtue of the way the world actually is
= Rationalists claim we can know some synthetic truths a priori, Empiricists disagree!

68. Different types of proposition:
A PRIORI – a type of proposition which is based on evidence from reason alone
e.g. ‘All bachelors are unmarried men’
A POSTERIORI – a type of proposition about the way the world is, which is based on evidence from experience (not necessarily sense exp.)
- e.g. ‘Snow is white’

69. Question:
Is then all a priori knowledge only analytic, and all a posteriori knowledge synthetic?
Rationalists would argue NO - SYNTHETIC
A PRIORI knowledge is possible!
challenge box, p.157
Darkened room thought-experiment, p.158

70. Rationalist claims:
That truths of maths and logic are true of the physical world (Descartes, Leibniz, Spinoza, Plato) , 168
That reason proves to us that at least a self exists (Descartes) - p
That we can know that God exists through reason (Descartes, Leibniz, Spinoza) – p.166-7,
That reason provides us with ‘Forms’ of things in the empirical world (Plato) –
That every event has a cause (Descartes, Kant) – pp.174-5

71. Empiricist Responses:
What does JS Mill claim about where our knowledge comes from?
What, for Mill, is the difference between mathematical truths and other kinds of truth?
What might be the problem with views such as Mill’s?
Other Empiricists allow for mathematics to be a priori, but still do not think the ‘synthetic a priori’ category can be filled by any claims. Why?
What is the remaining role of reason for such Empiricists?

72. Empiricist responses:
Either:
There is no a priori knowledge at all (even mathematical truths are inductively arrived at – J. S. Mill)
Or:
- The only thing we can know a priori are analytic truths – these don’t guarantee anything about the world we live in (reason only builds upon a posteriori knowledge)

73. Are mathematical truths synthetic?
Why do some rationalists claim that our knowledge of geometry gives us synthetic a priori knowledge?
Why is this claim problematic?
Extension:
Why do some rationalists claim that our knowledge of algebra gives us synthetic a priori knowledge?

74. Are mathematical truths synthetic?
Platonism: Yes – numerical relationships ‘exist’ independently of human cognition – we discover them through reason, and find them instantiated in the world.
Empiricism: No – numerical relationships are simply inferences (induction) from our sense experiences
Logicism: Maybe – numerical relationships can be derived from logic alone; this would appear to be derived (deducted) by reason alone

75. Are mathematical truths synthetic? (2)
Geometry: Euclidean geometry appears to be an accurate representation of the way the world is – see. p162
It assumes that space is ‘flat’
However… modern maths suggests that there are a number of different ‘types’ of geometry (some view space as curved) that can be simultaneously true of the world in different ways (i.e. we choose which one we use to measure the world by).

76. Descartes questions: 165:
Why did Descartes think that ‘Cogito ergo sum’ (I think therefore I am/exist) represented synthetic a priori knowledge?
Explain how this might be doubted. (165)
Extension:
Even if the cogito argument works, why might this not lead to the extent of synthetic a priori knowledge Descartes claimed? ( )

77. Descartes’ claims:
Descartes: existence of the self (cogito), existence of God, ‘clear and distinct ideas’ of mathematics and logic – can all be understood a priori, and apply to the world.

78. Plato’s claims: Pages 167-169
Explain how Plato claimed we could have synthetic a priori knowledge.
What is the problem with Plato’s claim?
Pages :
Summarise what most philosophers would think about the possibility of synthetic a priori knowledge today.

79. Plato’s claims:
Plato: the Forms (mathematics, geometry, moral, aesthetic)
We can understand by use of reason the ‘form’ (ideal version) of things and ideas that we otherwise come to by experience.
These ideas of ‘forms’ are actually in our minds before sense experience – they enable us to recognise that a particular concept or thing is a member of a particular class of things (e.g. this particular animal is a member of the class of ‘cat’).

80. Criticisms of Rationalism:
Ethical and aesthetic concepts do not seem susceptible to definition with mathematical precision – vagueness, cultural variation
Mathematical laws do not map straightforwardly onto empirical reality – we need empirical observation to confirm theories about the physical world
No logical inconsistency in supposing that the universe and physical laws could be different from way they are (not based on analytic truths)

81. Question:
Can you ‘Venn diagram’ the relationship between the terms analytic, synthetic, a prior and a posteriori according to i) Hume’s theory, ii) Descartes’ theory?
Can you think of any propositions which are both synthetic and a priori and which you know are true?

83. Overcoming Humean scepticism:
Leibniz:
God is a necessary, perfect being
His creation is thus necessarily perfect
All apparent evil in the world is contributing to making the best possible universe
Our own minds are too limited to see this using reason alone – we have to use empirical research to establish what could in principle be worked out by an all-powerful reason
The only being capable of such reasoning is God
Therefore synthetic a priori knowledge of the world is only possible for God.
Problem: assumes existence of God!

84. Summary:
Rationalism on its own has not provided any examples of synthetic a priori truths.
However, Kant’s theory presents more of a challenge to Empiricism…

85. Conceptual schemes
Series of ‘concepts’ or the potential for concepts, which organize our sense experience – sense-experience still vital to contribute the content which is worked on by concepts.
Kant’s categories: unity, necessity, substance, space and time
Chomsky: gives Kant a linguistic turn - language-learning faculty is ‘hard-wired’ into our brains, and reflected by universal grammatical rules.

86. Kant vs. Hume
Hume claims that we cannot have knowledge of causality – we merely perceive a succession of events to which we impute causation.
Hume’s scepticism awakens Kant from his ‘dogmatic slumbers’ (uncritical rationalism!)

87. Kant vs. Hume (2)
Kant wants to show that we can have objective knowledge about the world – that Newton is right, and Hume is wrong. In order to do this Kant sets himself two questions:
How can we have any experience at all?
How can we tell whether our experience is merely subjective (gives us only belief - Hume) or objective (gives us knowledge - Descartes)?

88. Kant’s Copernican Revolution
Before Kant, our relation to the world had been conceived as passive – our minds have the job of conforming to the way the world is.
With Kant, the relationship is reversed and we are active – the world of experience conforms to the way our minds represent it.
Our perceptions of the world are objective – they give us knowledge – truth – about the world.
E.g. Newton’s Laws of physics, geometry, etc.
The ‘categorical imperatives’ of reason when applied to morality (universalisable rules for all reasoning beings)

89. Two ‘intuitions’
Kant argues that to have any experience at all, we need to be able to tell the difference between things – in time and space. E.g. self and non-self.
Distinction between self and non-self is first step to distinguishing between our subjective experience and what is the case.
He calls our sense of space and time ‘intuitions’

90. Two ‘intuitions’, cont.
We can only have these intuitions if the world we perceive operates according to the law of cause and effect (causality).
Kant argues that in order for the relation of succession which we perceive in our experiences to be objective, it must be both necessary and irreversible.
How does he prove that we can know this is the case?

91. Kant’s Second Analogy from Experience: The House and the Ship
Someone tells you about two objects she has been looking at. One is a house, the other is a ship moving down a river. For both objects the person has taken a series of photos.
Question: Which set of photos could you put in order of the time they were taken, and why?

92. The House and the Ship (2)
One of these observations can affirms the law of causality, thus our sense of time, and thus objective experience of the world, whilst the other is an example of where we have only subjective perceptions.
Which is which, and how can you tell?

93. Kant’s conclusion:
We are only able to differentiate between an object and the representations through which we apprehend it if the representations are necessarily ordered in some defined way by a particular rule.
This format serves to distinguish one true mode of representation from any other.

94. Summary:
Kant brings together Rationalism and Empiricism, arguing that neither on their own can account for our knowledge of the world, but that both a priori concepts (‘categories’) and sense data are required.
Subsequent philosophers have explored whether such categories are indeed a priori, or whether they are culturally relative (if they are, their claims about the world could only be checked via empirical, a posteriori confirmation).

95. Summary 2
If we cannot show that a priori categories are universal, then we are left in Hume’s position: sceptical Empiricists, who proceed according to sense experience, but who accept that this itself might be unreliable.
Such philosophers are generally called anti-foundationalists, and sometimes anti-realists

96. Questions: What is a priori / a posteriori knowledge? (2 marks)
How does Descartes define God? (2)
Outline the idea of the tabula rasa. (5)
Outline what is meant by an innate idea. (5)
Outline and explain Hume’s Fork. (5)
Explain and illustrate a necessary truth/analytic statement/contingent truth, etc. (5)

97. Questions:
Explain how we can acquire a priori knowledge. (9 marks) pp
Explain the difference between inductive and deductive arguments. (9) pp
Explain the difference between necessary and contingent truths. (9) p.154
Explain the difference between synthetic and analytic statements. (9) p.154
Explain why Locke opposes innate ideas. (9)
Outline and explain Descartes’ trademark argument for the existence of God. (9)
Outline and explain Descartes’ argument against trusting sense experience. (9)

98. Quantum Mechanics: http://www.youtube.com/watch?v=DfPeprQ7oGc
(Double slit experiment)
(6 mins) (implications)
(10 mins) (implications)
Non-Euclidean Geometryhttp://

99. Questions:
Assess whether all our knowledge comes from experience. (15)
Can reason alone provide substantive (synthetic) knowledge? (15)
Is Descartes/Leibniz/Plato/Locke/Hume right to claim that…? (15)

102. Questions, 2
Do the claims of quantum physics and non-Euclidean geometry disprove Rationalism? Or do they just show that the world of experience – but not theory - is determined by the categories?
Might the application of the categories depend on our purposes?

103. Relativism - Implications:
If history suggests that conceptual schemes can change over time, and anthropology suggests that different cultures have different conceptual schemes, then…
Hume was (sort of) right: our understanding of the world is determined by habit and custom.
So, conceptual schemes are gained a posteriori – perhaps via language.
…and there is no ‘final’ True way of understanding the world available to us.

104. Magic vs. Science, etc.
Why can it be so difficult to persuade someone who seems to hold a different belief about the world that your view is correct?
Can you think of any other examples where people seem to ‘reach bedrock’ (Wittgenstein) and be unable to persuade each other of their views?
Can you think of a convincing way of persuading someone in such a case?

105. Some areas of supposed relativism:
Morality
Politics
Religion
Aesthetic evaluation (art)
Alternative medicine vs. orthodox scientific medicine

106. But:
Can we really not translate different ways of seeing the world into one – expanded – way of seeing the world?
Compare witchcraft and science:
both offer an explanation of the world and ways of controlling natural processes
which can perform the job of controlling natural processes better? Are they really equal?

107. Newton’s Laws

108. Question:
In what ways does Kant’s theory refute Hume’s scepticism?

109. Homework:
Explain what is meant by a priori and outline one reason why the a priori is
philosophically significant. (15 marks)
‘All ideas derive from the sense experiences which they copy.’ Discuss. (30 marks)

110. Criticisms (2):
Can Hume’s theory support itself? Has it enough empirical evidence to support it?
Theory doesn’t rule out solipsism (no external world) or account for shared ideas.
Without some means of interpreting sense data, how are we to make sense of it? ‘A blooming, buzzing confusion’ (William James)

111. Reason and Experience 7: How do Empiricists think we acquire our ideas
Aim:
to be able to explain how Empiricists differ from Rationalists in their understanding of how we gain knowledge.

112. Homework:
Outline Locke and Hume’s theory of concept acquisition (9 marks)

113. Hume’s epistemology:
Draw Hume’s theory in a diagram or table, giving examples.
What might be problematic with arguing that all our ideas are derived from sense experience?

114. Hume’s Fork: terms to use:
Analytic
A posteriori
Deductive
Tautologies
Matters of Fact
A priori
Synthetic
Knowledge
Belief
Matters of Fact
Inductive
Relations of Ideas

115. Homework:
Outline and illustrate the empiricist theory of concept acquisition. (15 marks)

116. Descartes’ ontological argument for God – criticisms:
Gassendi
Caterus
Kant
Hume
Sum up each of these philosopher’s views in a sentence!

117. Descartes’ argument for God – criticisms (page 147):
Gassendi:
Existence not part of the idea of God as a supremely perfect being
But if we think carefully enough, do we not perceive that all God’s qualities are interlinked? E.g. omnipotence, omniscience, necessary existence (not depending on anything else in order to exist)

118. Descartes’ argument for God - criticisms:
Caterus:
Ontological argument shows only that concept of existence is inseparable from concept of God. Descartes’ argument only works if God does exist!
But doesn’t necessary existence entail actual existence?

119. Descartes’ argument for God - criticisms:
Kant:
Existence isn’t a ‘property’ that things ‘have’ by virtue of logic (analytic) – only true by virtue of actuality (synthetic)
e.g.
- A dog is a mammal
A dog ‘exists’ – existence is a different kind of property.