AQA Philosophy Unit1 AS (Knowledge and Experience)

Different types of knowledge:
-  Acquaintance knowledge (e.g. I know Oxford well)
- Ability Knowledge (e.g. I know how to ride a bike)
- Propositional knowledge (e.g. I know that eagles are birds)
First 2 types of knowledge are interesting but we are only concerned with Propositional knowledge.
We intuitively make a distinction between belief and knowledge:
- People can belief propositions that aren't true: but if you know that P, then P must be true. E.g. is you claim   that flamingos are grey, and you think you know this you are mistaken. If flamingos are not grey, but pink then you can't know that they are grey. Of course you can believe that they are grey, but that is the difference - beliefs can be false. You can't know something is false: if it is false, then you don't know it. You have made a mistake, believing it to be true when it is not.
- Another distinction is that people can have true beliefs without any evidence or justification for their beliefs. For example, someone on a jury might think that the person on trial is guilty just from the way they dress.Their belief, that the person is guilty, might be true: but how someone dresses isn'e evidence for whether they are a criminal. So belief can be accidentally true, relative to the evidence the person has: if it is, it  isn't knowledge. Someone could hold a belief that is, in fact true, even whey they have evidence to suggest it is false. For example, there is a lot of evidence that astrology doesn't make accurate   prediction, and my horoscope has often been wrong.

The contrast between analytic and synthetic propositions is a contrast between types of proposition.
Analytic:
- A proposition is analytic if its true or false just in virtue of the meanings of the words.
- Many analytic truths, such as 'squares have 4 sides', are obvious, but some are not, for example, 'In five     days time, it will have been a week since the day which was tomorrow three days ago'.
Synthetic:
- A proposition is synthetic if if is not analytic, that is, it is true or false not just in virtue of the meanings of the  words, but in virtue of the way the world is, for example 'ripe tomatoes are red'.   The contrast is, in the first instance, about how we know enter a proposition is true.
A priori: 
- Is knowledge of proposition that do no require (sense) experience to be known as true. For example, 'Bachelors are unmarried'. If you understand what the proposition means, then you can see straight away that it must be true. You don't need to find bachelors and ask them if they are married or not.
A posteriori:
- Propositions that can only be established through experience are a posteriori. e.g. 'Snow is white.' 
- When applied to propositions, the a priori/ a posteriori distinction is about how to check or establish           knowledge. 

- On first reflection, it might seem that the distinctions line up neatly: that a proposition that is analytic is also   known a priori: and that a proposition that is synthetic is known a posteriori.
- 'Bachelors are unmarried' is not only a priori, but is also analytic. 'You are reading this book' is synthetic       and a posteriori as it can only be known through sense experience. But is this alignment correct?
- All analytic propositions are known a priori. Because they are true/false just in virtue of the meanings of         the words, we don't need to check them against sense experience to know whether or not they are true.
- However, just because all analytic propositions are a priori does not mean that all a priori propositions are     analytic.
- Perhaps there are some a priori propositions that are synthetic. So we must ask whether all synthetic are     known a posteriori.
- Or do we have some knowledge, apart from knowledge of analytic truths, that does not come from sense     experience? Disagreement. 
Rationalism: The theory that there can be a priori knowledge of  synthetic propositions about the world (outside the mind); this knowledge is gained by reason without reliance on self experience. 
Empiricism: The theory that there can be no a priori knowledge of synthetic propositions around the world (outside the mind), that is, all a priori knowledge is of analytic propositions, while all knowledge of synthetic propositions must be checked against sense experience. 

- Locke argues that all ideas are derived from sense experience. The mind is a 'tabula rasa', empty at birth. 
- Lock argues that there is no truth that everyone, including children and idiots, assents to - so no truth is innate.
- Moreover, Locke goes on to suggest that in fact there is no universal assent. - Locke, in 'An Essay Concerning Human Understanding', suggests that the concept of universal assent in fact proves nothing, except perhaps that everyone is in agreement; in short universal assent proves that there is universal assent and nothing else. 
- Even a phrase such as "What is, is" is not universally assented to, infants and severely handicapped adults do not generally acknowledge this truism. 
- Locke also attacks the idea that an innate idea can be imprinted on the mind without the owner realizing it. 
- To return to the musical analogy, we may not be able to recall the entire melody until we hear the first few notes, but we were aware of the fact that we knew the melody and that upon hearing the first few notes we would be able to recall the rest.

Hume believes that we are immediately and directly aware of 'perceptions'.'Perceptions' are divided into 'impressions' and 'ideas'. Both Locke and Hume divide impressions into impressions of 'sensation' and those of 'reflection'. Impressions of sensation derive from our senses, such as seeing a car; impressions of reflection derive from our experience of our mind, such as feeling emotions.(Locke also includes awareness of mental processes, such as reasoning, believing, willing and so on) Hume then argues that ideas are 'faint copies' of impressions.
- Think what it is like to see a scene or hear a tune; now what it is like to imagine or remember that scene or tune. The latter is weaker, fainter. And so there are ideas of sensation (for example, the idea of red) and ideas of reflection (for example, the idea of sadness). Concepts are a type of idea.
- So his theory of how we acquire ideas, as follows by coping them from impressions, is a theory of how we acquire concepts.- So Locke and Hume have slightly different versions of how we first acquire ideas with which we can think.
- We start with sense experiences of the physical world and experiences of our minds; for Locke, this gives us ideas once we can employ our memories to reflect on the experiences; but this it makes it sound as if the experiences, remembered, are the ideas with which we think.
- Hume correct this: it is not sensory impressions themselves, but copies, that we remember and use in thinking.
 

- The basic building blocks of all thought and experience are simple impressions - single colours, single shapes, single smells and so on. And to each there is a corresponding idea.
- But we soon begin to unite these simple ideas in more complex ones, for example, we identify one and the same thing (a dog, say) as having a particular colour, shape, smell.
- So we can think of 'that thing', where the ideas of 'that thing' is made up on many ideas of colour, shape, smell.
- This is a complex idea; in this case, it is a complex ideas that had a kind of corresponding 'complex impression' in that we can, through our various senses acting together, experience the particular dog.
- We can also from complex ideas by abstraction, for example, the concept DOG doesn't correspond to any one particular set of impressions or any single dog.
- When we abstract, we ignore certain specific features and concentrate on others: so to develop the concept DOG, we ignore the different colours and different sizes are, picking out other features, such as four legs, tail, bark, hairy. 

- The view that all ideas derive from sense exe prince is very appealing in many ways.
1. There are complex ideas that seem to correspond to nothing our sense experience, for example,                   unicorns and God. (Whole many of us have seen a picture of a unicorn, someone had to invent 
    the idea without seeing a picture) So how can it be true that all ideas derive from sense experience?
2. Empiricists respond that  all complex ideas are composed of simple ideas, and all simple ideas are                 copies of impressions. This is easy to see in the case of unicorns: we have experience of horses                 and of horns and of whiteness: if we put them together, we get a unicorn. Also, you can't ask a blind man      to explain the colour of yellow as they have no concept for it. 
3. Hume and Locke argue that in creating new complex ideas, we can only work with the materials that             impressions provide. No idea, no matter how abstract or complex, is more than putting together, altering       or abstracting from impressions. It is important to notice that there are many ways in which we do this;         combination and abstract are two of the most important.

We can challenge empiricists to give us their analysis of complex concepts such as Necessity , Causation, Substance or Self. If they cannot give us a satisfactory analysis of how we derive these       concepts from experience, that is a reason to think that the concepts derive from elsewhere - either they are innate, or they are reached using a priori reasoning. 
- Hume accepts that these four particular examples cannot be derived from experience.However, his response, for each each of these examples, is that the concept - as we usually think of it - has no application.The concepts (and therefore are thoughts about Necessity, Causation, Substance & Self) are confused; in their place, he suggests a clearer way of thinking, using concepts that can be derived from experience.
- For example, we have no experience of our 'selves' - we only experience a continually changing array of thousands of feelings. To come up with the idea of SELF (meaning each of us one and the same thing over time), we've confused similarity (the similarity of our thoughts and feelings from one moment to the next) with identity (the identity of a 'thing' to which such mental states belong)
- We do the same thing again with the idea of a physical object as a 'thing' or 'substance', meaning something that exists indecently, in its own right.
- The concept of PHYSICAL OBJECT is of something independent of experience existing in three-dimensional space. But how can experience show us that something exists independently of experience?

- I see my desk a few moments later I see it again. If my 2 experiences are of the same same desk, the the desk existed when I wasn't looking at it.
- But I can't know that my experiences are of one and the same desk; I can only know that the two experiences are very similar.- In coming up with the concept of physical object that exists indecently of my experiences, I have confused similarly with my identity. 
- So Hume concludes, the concepts SELF and PHYSICAL OBKECT (and SUBSTANCE) are confusions, they aren't coherent. But, we can object, this makes most of our common sense idea of the world wrong.- This is unacceptable. If an empiricist analysis makes such concepts 'illusory' we may feel empiricism is too challenging to accept. Our concepts are coherent. The fact that we cannot derive them from experience shows that they are innate (or known through rational intuition
- So the difficulty empiricists have in explaining our most abstract complex concepts is an argument that these concepts are not derived from experience.
- But are they innate or arrived at by rational intuition? One reason to think they are innate is that children use these concepts early on in life.
- Rational intuition is likely to come late in life, when a persons rationality if better developed.
- So rationalists accept Hume's argument that we can't derive these ideas from sensory experience alone. Rather than reject or reinterpret the concept, they keep the concept, arguing that our experience trigger the concept, and we begin to conceptualise experience in terms of physical objects and selves.

Hume argues that we can have knowledge of just two sorts of thing: the relation between ideas and matter of fact. By relations of ideas, Hume means propositions such as 'All sons have fathers' (about the ideas of 'son' and 'farther' and 'If A is longer than B, and B is longer than C, then A is longer than C' (about the idea of length.
- His distinction was developed by later philosophers. Understood in terms of the distinctions analytic/synthetic and a prior/a posteriori. 
- In effect, Hume argued that all a priori knowledge (relation of ideas) must be analytic, while all knowledge of synthetic propositions (matter of fact) is a posteriori. Anything we know that is not true by definition, every 'matter of fact', we must learn and test through our senses.
'Matters of Fact':
- The foundation of knowledge of matters of fact, Hume argues, is what we experience here and now, or can remember. All our knowledge that goes beyond what is present to our senses or memory, he claims, rests on casual inference. 
- If I receive a letter from a friend with a French postmark on it, I'll believe that my friends is in france  because i will infer from the postmark to the place and if the letter was posted by my friend, then I believe that he or she is in France. 

 - And how do I know all of this? I rely on past experience - in the past, I have experienced letters being posted, I have seen different postmarks, I have found that postmarks relate to where you post something, and so on.
- I can't work out what causes what just be thinking about it. It is only our experiences  of effects following causes that bring us to infer from the existence or occurrence of some cause to its effect, or from some effect to its cause.
- Does this give me complete certainty? Is this proof that the letter was posted in France? No says Hume: Knowledge of matters of fact, beyond what we are experiencing here and know, relied on induction and reasoning about probability. 
- An inductive argument is an  argument whose conclusion is supported by its premise, bur is not logically entailed by them. That is, if the premises are true, the conclusion is likely to be true. 
- An inductive argument is an  argument whose conclusion is supported by its premise, bur is not logically entailed by them. That is, if the premises are true, the conclusion is likely to be true. 
- A letter with a french postmark is most likely posted in France, because most letters with French postmarks were in fact posted in France,- This is induction through 'inference to the best explanation.'
- A deductive argument is an argument whose conclusion is logically entailed by its premises, that is, if its premises are true, the conclusion cannot be false. Famous example:
Premise 1: Socrates is a man. Premise 2: All men are mortal. Conclusion: Socrates is mortal.

- Desartes argues that we can establish the existence of the mind, the physical would and God through a priori reasoning. He begins his investigation into what we can know by attacking sense experience. He explains that you can doubt all your sense experiences. You can doubt even the senses that seem most certain.One, Optical Illusions - Our senses can be unreliable as they can be fooled, for example if you put a pencil in water it will appear bent to the eye, however in our minds we know this to be false but our eyes do not. Two, The Dreaming Argument - He said that when we are sleeping and dream we cannot tell whether we are actually asleep or not, or whether our senses are correct. He says that when we are 'awake' and see an apple, how do we know it's really there? We may be sleeping and it may not exist at all. Evil demon: suppose all of our sense experiences are produced to us by an evil demon who wants us to revive everything you experience is false.n a modern version, replace the evil demon with a supercomputer, as in the film The Matrix. Can you tell if you aren't just from sense experience?  If, as Hume argues, sense experience is the foundation of knowledge about what exists then we are in trouble, because we cannot know that our senses experiences is a good guide of what exists.Descartes then  argues that there is only one thing he can be completely sure of, even if the evil demon exists: that he thinks, and from this, that he exists. 'cogito ergo sum' = "I think, therefore I am " He cannot doubt that he thinks, because his doubting is a kind of thinking. If the demon were to make him doubt his thinking, that would only show that he is. That he has got to a point of pure reasoning. This leads to the theory of solipsism (idea that only you exist). The truth is 'seen' by intuition - we recognise that it is true just be considering it.

- Descartes then  notices that even though he cannot doubt he exits, he can continue to doubt whether he has a body, after all, he only believes he has a body as a result of sense experience, and so the demon could be deceive him about this. From all this he concluded it is possible he doesn't have a body- So, Descartes believed he had established another truth about what exists, just be a priori intuition and demonstration - the mind can exist separately from the body.- Descartes later argues that there are only 3 options of what causes these experiences: a real external world of physical objects, a demon or God.- If the cause was God was this would mean that God is a deceiver because He would have created us with a very strong tendency to believe something false (the physical world exists) - And if it was a demon, than if God exists, God is as good as a deceiver, since God is allowing the demon to deceive us. However, Descartes, argues God is perfect by definition. - Because we know that God is perfect, we know that God isn't a deceiver. So if God exists then there most be an external world.- Decartes offers two reasons, both a priori, for the existence of God - one the ontological argument (idea that God is innate) one is the Trademark argument. The idea that God exists just from the fact we have an idea of God. This idea is like the 'trademark' our creator has stamped on our minds'.- Decartes agues that the idea of God is innate, and could donly have been causes by God, because as imperfect and finite beings, we could not come up with the idea od something infinite and perfect.-  Since Descartes believes he has demonstrated God exists he concludes that we know the external world of physical objects exist. Not because sense experience show us that it does, but through a prior intuition and demonstration. 

There are two distinguishable elements of experience - the data of the senses and then the interoperation of this data by a set of concepts. On these data, different people would impose different conceptual schemes (usually thought of is cultural in some way) 
- POINT: They object to Locke - our senses to don 'let in' ideas; rather, before we can form ideas, we must interpret what our senses tell us.It was then argued that these different conceptual schemes may be irreconcilable - that we can't translate from one into another.
- The strongest form of this 'conceptual relativism' claims that because their conceptual schemes are fundamental to how people experience and understand reality, people with different conceptual schemes have different realties.One famous version of this view is known as the Sapir-Whorf hypothesis, deriving from the linguist Edward Sapir and anthropologist Benjamin Whorf. Struck by the difficulties in translating between languages.For example, Whorf worked with Hopi Indians, and argued that the way they talked about time could not be expressed in english.But this isn’t just a matter of language – their language is a reflection of how they think, of their concepts: 'We are inclined to think of language simply as a technique of expression, and not to realize that language first of all is a classification and arrangement of the stream of sensory experience which results in a certain world-order. 

- If there are different schemes, but we can translate between them, then Whorf is wrong – this doesn’t lead to ‘relativity’. However, the view that there are different conceptual schemes and that we cannot translate between them leads to the conclusion that truth is relative to conceptual schemes. 
- Some thinkers have gone so far as to claim that reality is relative to conceptual schemes, so that people with different conceptual schemes experience different worlds.But this is very difficult to defend, and it may not even make sense.
- First, it supposes that language somehow ‘constructs’ reality – but the world would still exist even if no one spoke any language. It existed before language, after all.
- Second, as the quotation from Whorf indicates, the theory is usually developed by contrasting something that is the ‘same’ (physical evidence, sensory experience) with the differing interpretations imposed by different conceptual schemes. 
- So there is something that is ‘real’ which is ‘outside’ or ‘before’ or ‘beyond’ all interpretations.
 - The weaker claim, that truth is relative to conceptual schemes, says this: because there are conceptual schemes which cannot be translated into each other, a proposition in one scheme can be true without being something that the other scheme can express at all.So there is no one set of truths – or Truth – which describes how the world is.
- (Again, if we can translate between the schemes, then any true proposition in one scheme has an equivalent translation in another – so truth is not relative.)

- Conceptual relativism looks like an empirical claim – we need to go and find out whether there are any conceptual schemes which are not translatable But some philosophers have argued that the account of the relation between experience and conceptual schemes given above doesn’t make sense. 
Whorf says that language (or the conceptual scheme embodied in a language) ‘organizes’ or ‘arranges’ our experience of the world.
- You can only organize something if it has parts or contains objects – you can organize the clothes in a wardrobe, but you can’t organize a wardrobe itself.
 - If we claim that a conceptual scheme organizes our ‘experience’, then we must think of  experience as comprised of experiences. 
 - So here is something that different conceptual schemes all have in common – the set of experiences (that they organize differently). 
 - But in talking about these experiences, how do we pick them out? We can only do so in familiar ways – feeling cold, seeing a plant, smelling a rose. 
- Any conceptual scheme which starts with these sorts of experiences will end up very similar to our own, and so we will be able to translate between the two schemes.
 - Of course, there may be parts of a scheme that cannot be translated. 

- And perhaps this leads to a mild form of conceptual relativism. But it will be very mild. Because there are parts of the scheme that can be translated, we can use these to understand the parts that we cannot translate. We can then add these new thoughts into our conceptual scheme – we can expand our concepts. So we don’t end up with the view that there is no one set of truths that describes reality, just that we will need a very expanded conceptual scheme to provide the means for expressing these truths. 
- The metaphor of ‘organizing’ should perhaps be rejected. But that doesn’t mean we avoid conceptual relativism. 
- The second part of the answer assumes that we can always combine different conceptual schemes. But this is questionable. 
- A popular example is given by colour concepts. Different cultures, it seems, carve up the colour spectrum differently. Suppose that one culture uses just one concept in thinking about what we think of as two colours, blue and green. 
- We cannot combine all three concepts in one scheme, since they conflict.
- In our scheme, we can say – truly – ‘it is green but not blue’; in theirs, it is impossible to say this. Either you think of blue and green (as we would say) as two separate colours or as one colour.
- However, it is misleading to say that ‘truth is relative to conceptual schemes’. This would suggest that that what is true according to one scheme is false in another.

- There are complex ideas that seem to correspond to nothing in our sense experience, e.g. unicorns and God. (While many of us have seen a picture of a unicorn, someone had to invent the idea without seeing a picture.)So is it true that all ideas derive from sense experience? 
- Empiricists respond that all complex ideas are composed of simple ideas, and all simple ideas are copies of impressions.This is easy to see in the case of unicorns: we have experiences of horses and of horns and of whiteness; if we put them together, we get a unicorn.
- Hume and Locke argue that in creating new complex ideas, we can only work with the materials that impressions provide. No idea, no matter how abstract or complex, is more than a putting together, altering or abstracting from impressions. It is important to notice that there are many ways in which we do this; combination and abstraction are two of the most important. 
- But we can challenge empiricists to give us their analysis of complex concepts, such as necessity, causation, substance or self. If they cannot give us a satisfactory analysis of how we derive these concepts from experience, that is a reason to think that the concepts derive from elsewhere – either they are innate, or they are reached using a priori reasoning. Hume accepts that these four particular examples cannot be derived from experience.
- However, his response, for each of these examples, is that the concept – as we usually think of it – has no application.

The concepts (and therefore our thoughts about necessity, causation, substance and the self) are confused; in their place, he suggests a clearer way of thinking, using concepts that can be derived from experience.
 - For example, we have no experience of our ‘selves’ – we only experience a continually changing array of thoughts and feelings. (Treatise on Human Nature, I.IV.6) To come up with the idea of SELF – meaning each of us as one and the same thing over time, we’ve confused similarity – the similarity of our thoughts and feelings from one moment to the next – with identity – the identity of a ‘thing’ to which such mental states belong. we do the same thing again with the idea of a physical object as a ‘thing’ or ‘substance’, meaning something that exists independently, in its own right.
- The concept of PHYSICAL OBJECT is of something independent of experience existing in 3-dimensional space. But how can experience show us that something exists independently of experience?I see my desk; a few moments later, I see it again. If my two experiences are of one and the same desk, then the desk existed when I wasn’t looking at it.  - But I can’t know that my two experiences are of one and the same desk; I can only know that the two experiences are very similar. 
- In coming up with the concept of a physical object that exists independently of my experiences, I have confused similarity with identity.So, Hume concludes, the concepts SELF and PHYSICAL OBJECT (and SUBSTANCE) are confusions, they aren’t coherent.
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 - But, we can object, this makes most of our commonsense idea of the world wrong. This is unacceptable. If an empiricist analysis makes such concepts ‘illusory’, we may feel empiricism too challenging to accept. 
- Our concepts are coherent. The fact that we cannot derive them from experience only shows that they are innate (or known through rational intuition).  - So the difficulty empiricists have in explaining our most abstract complex concepts is an argument that these concepts are not derived from experience.
- We can also rephrase the objection, to attack empiricism a different way. The empiricist theory has two claims: that complex ideas are built out of simple ideas, and that these are copied from experience
- The previous objection looked at the problem of deriving a concept from experience. We could instead object that complex concepts cannot be built out of simple ones (leaving aside the question of experience):
- Hume challenges us to find an example of a complex idea that cannot be analysed into simple ideas, we can respond by suggesting one and challenging empiricists to provide an adequate analysis. 
- For example, attempts to analyse philosophical concepts like ‘knowledge’, ‘truth’, ‘beauty’ into their simple constituents have all failed to produce agreement. Perhaps this is because they don’t have this structure.

- Hume discusses a second objection: If someone has seen all shades of blue except one, and you present them with a spectrum of blue with this one shade missing, they will be able to form an idea of that shade, which they have nevertheless never seen.
- So here is an example of an idea which has not been copied from an impression.If it is possible that we can form an idea of a shade of blue without deriving it from an impression, is it possible that we could form other ideas without preceding impressions? 
- How can we allow for the missing shade of blue, but hold on to the view that all ideas are derived from experience? One solution is to say that all (coherent) ideas can be derived from experience. We can only create ideas that correspond to something we can experience.
- The idea of the missing shade of blue fits this perfectly, and the definition still ties ideas to experience.
- A different solution maintains the stronger, original claim that all ideas are derived from impressions as a general principle, but explains both why the missing shade of blue is an exception and that exceptions to the rule must be limited. 
- The explanation is this: the simple impressions of different shades of blue are not unrelated to each other, as they can be arranged in a sequence of resemblance. 
- From the arrangement, we can form the idea of the missing shade, drawing on other similar impressions we already have. But if we have no relevantly similar impressions which strongly resemble the missing impression, we cannot form the missing idea.

- Both Hume and Locke appear to assume that sense experience gives us discrete ideas directly. As first examples of simples ideas Locke lists ‘Yellow, White, Heat, Soft, Hard, Bitter, Sweet.’ 
- He supposes that what makes all experiences of yellow into experiences of yellow is objective patterns of similarity between the experiences - yellow things all look ‘the same’. Locke suggests that experiences are already ‘packed’ into ‘the same’ and ‘different’ 
- To stay with the example of colour this doesn’t seem to be true. First the colour spectrum is not divided into distinct parts of red, yellow and so on; it is continuos.
- Second, there are many shades of yellow; to call them all yellow is abstract from their individual different shades. Putting these two points together, we realize that acquiring the concept ‘yellow’ is not a matter of copying an impression; no experience comes neatly packed up as an experience of ‘yellow’.
- To learn the concept ‘yellow’ is to learn the range and variety of colours to which ‘yellow’ refers.How is this done? In order to learn ‘yellow’, we have to pick out and unify our experiences of the very varied things that are yellow.
- But if all we have to go are the many various experiences, how are we able to classify them in this way, distinguishing yellow from not yellow? Well aren’t all shades of yellow more similar to other shades of yellow than to shades of another colour (e.g. orange?) 

- All we need to do is read off, or copy, our concepts from experience. Even if there are objective similarities and differences between experiences we must still notice and pick out these similarities to form the concept.
- In order to do this, to know what is ‘the same’ or ‘different’, we must already be able to classify our experiences. The same or different in what way? Which similarity are you identifying? In what ways are things that are a shade of yellow similar? - In being yellow! 
- To pick out the common features between different experiences, we must already possess the concept that unites them. (Of course, this is not to say that you have a name for the concept yet)
RESPONSE: To this, empiricists say that we don;t need to notice and pick out the similarities - they simply cause the concepts directly. However, if the objection is right then all our concepts - or at least, all our simple concepts - must be innate. What this means is that the mind is innately set yo to interpret and classify experience in particular ways. 

- The idea of triggering is often used in the study of animal behaviour. For example, in some species of bird, a baby bird need only hear a little bit of the bird song of its species before being able to sing itself. 
- There has been far too little experience of hearing the song from other birds for it to learn from experience; rather the experience has triggered its innately given song.
- The contemporary philosopher Peter Carruthers notes that there are many developments in our cognitive capacities that are genetically determined (Human Knowledge and Human Nature, p. 51).  
- For example, infants cannot see further than approximately 12 inches when first born. Within 8 weeks, they can see much further. This development of the eye is genetically encoded. The ability to learn and speak a language develops around 18 months. Just as capacities develop, so why not concepts and knowledge as well? 
-  At a certain point in development, a point that is genetically determined, children begin to use an idea for the first time, but that idea cannot be acquired from experience. This is not to say that experience has no role – a child must be exposed to the relevant stimuli for the knowledge to emerge, e.g. children can’t learn language unless people around them speak.  
- Here is a clear sense in which the idea is innate, but which differs from Locke’s definition. With this redefinition, the idea of innate ideas is not as contradictory as Locke makes out. What shows that the idea is innate is that it cannot be derived from or justified by experience. But are there good reasons to think we actually have any innate ideas? 

 - Defenders of the idea of innate ideas define them as ideas which we can’t have derived from experience, but which experience ‘triggers’. But can we make sense of this view, and are we right to think of such ideas as innate?
- First, if experience is a necessary ‘trigger’, are nativists really just saying that to have an innate idea is just to have the capacity to come to know the idea?
 - But this would reduce all ideas to innate ideas. We have the capacity to discover such empirical facts as the height of Mount Everest and the number of planets in the Solar System, but these are clearly not known innately, but derived from and justified by experience.
-   But this isn’t what nativists claim. It is not just a general capacity to learn which is innate; empiricists have always allowed that these general capacities (memory, association, and so on) are innate.
- Locke and Hume certainly thought the structure of our senses and our general abilities to learn were innate. However, as we specify the structure of our senses more and more, we come closer to saying that these capacities of the mind are innate forms of information about experience.
- And so the nativist claims that the idea we form has not been learned (inferred or derived or abstracted) from experience, but merely triggered by experience. This is specific to just those ideas that are innate, not all ideas.
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-  But are we right to say that the idea is ‘innate’? Or have we changed the meaning of the term? We can cite Carruthers’ story, and say that the idea is innate in the sense of it being encoded genetically that we will develop that specific idea (not just a cognitive capacity) at a certain point or under certain conditions. 
-  Alternatively, we can defend a more general theory of human nature: Descartes thought that to speak of innate ideas is, roughly, to speak of dispositions we have as part of our nature to form certain thoughts through reasoning and self-reflection. (In this, Descartes connects innate ideas to a priori knowledge through intuition and deduction.) 
-This distinguishes the capacities (a priori reasoning and self-reflection) we have which deal with innate ideas from the capacities we have to learn a posteriori truths (the senses and a posteriori reasoning).
-Locke objected that if an idea were innate, all children and idiots would know it. To this, we may reply that the children have not had the experience or reached the point in development when the idea comes to consciousness; and in idiots, cognitive capacities have not developed normally, and so neither has innate knowledge.
- But if innate ideas do not derive from experience, just where do they come from? Carruthers suggests the cause is evolution, as what formed our genetic code. Descartes argued that our rational nature, including innate ideas, is implanted by God. Plato argues that they derive from a previous, non-physical existence.

- In Syntactic Structures, the linguist and philosopher Noam Chomsky has argued that our knowledge of language, or more accurately, grammar is innate. 
- A key part of grammatical knowledge is whether a sentence is ‘allowed’ in a language, e.g. ‘The sleepy cat is on the mat’ is fine, but ‘The sleepy cat look there on the mat’  is not.
- To learn from experience, children would need to use memory, induction from examples, and inference to what grammatical rules best explained the examples of language they experience. 
- Chomsky’s central argument, called ‘the poverty of stimulus’ argument, is that children learn linguistic grammar accurately so fast, and from very poor information, that their knowledge of grammar can’t have derived from experience.
- Children arrive at grammatical rules – not consciously, but in being able to construct and identify grammatically correct sentences – first, on the basis of far fewer examples than they can classify; second, many of these examples are ungrammatical – when speaking, we often say things like ‘The cat… look there – on the mat’, i.e. we speak in incomplete, interrupted sentence phrases; and third, the mistakes children make are not often corrected. 
= And so children cannot be learning grammar from their experience of language. Instead, exposure to language triggers their innate knowledge of grammar. 

- Many philosophers believe that, in the Phaedo, Plato defended the view that in judging that two sticks are of equal length, we are using an idea of EQUAL that we cannot have gained from experience. 
- Nothing is exactly equal in experience, but only ‘almost equal’. But the concept ALMOST EQUAL contains the concept EQUAL. So where does it come from? If we do not learn our concepts from experience, we must already know them. This knowledge must come from before birth. (The main aim of the Phaedo is to argue that the soul is immortal, and Plato uses the issue of innate concepts to support this claim.) - Plato takes concepts to be a type of knowledge, and so his argument for innate concepts is also an argument for innate knowledge. We are able to classify our experiences, e.g. that two sticks are equal, by comparing them with our knowledge of what Plato calls the ‘Forms’. 
- A Form is a perfect idea, which exists independently of us. Plato argues that all objects we experience through our senses are particular things (The Republic, Book V (476f.)). We don’t ever sense anything ‘abstract’, but always some individual thing or other. For example, we only ever see this particular beautiful thing or that particular beautiful thing, but we never see ‘beauty’. 
- But, obviously, more than one thing can be beautiful. Beauty is a property that more than one thing can have. So, Plato claims, if many different things can be beautiful, then there is something they share in common, as follows beauty. So there must be something which is ‘beauty’, even though we never experience beauty itself through our senses. The Form of Beauty manifests itself in all the different things, in all the different ways, we call ‘beautiful’.

- But why should we agree that just because many different things can be beautiful, there is some thingwhich is ‘Beauty’? Because, Plato goes on to argue, Forms exist independently of particular things. 
- All particular beautiful things could also be destroyed, yet that won’t destroy beauty itself. So beauty must be a separate thing, existing in its own right. So, he concludes, particular things ‘share’ or ‘participate’ in the Forms, but these exist independently. 
- To have the concept EQUALITY is to know what equality is, and this is to know the Form of equality. This is the knowledge we gained before birth. It is because we know the Form of equality that we can have the concept EQUALITY, which in turn allows us to classify experiences of sticks as ‘equal’ or not. We remember or recollect our knowledge of the Forms in applying concepts. 
- Plato demonstrates this idea of recollection in a famous example in the Meno. Socrates talks to a slave boy about a theorem in geometry. (The question is this: if you have a square and you want to create another square with twice the area, how do you work out the size (the lengths of the sides) of this second square?)  
- The slave boy has not been taught geometry, and yet is able to discover the right answer in response to Socrates only asking questions. How is this possible? The boy didn’t have experience of geometry, and wasn’t taught it. It must be that Socrates’ questions triggered the knowledge he had from before birth, but had forgotten. 

- An empiricist can reply that, in fact, the concept ALMOST EQUAL does not contain the concept EQUAL. Instead, ALMOST-EQUAL is a simple concept derived from sense experience of comparing objects. 
- Plato is talking about equal length; we have experiences of two sticks not being the same length. They always differ by some (possibly tiny) amount. We form the concept EQUAL (as in equal length) by abstracting from the experience of differing lengths – two sticks are equal when they differ by no length. 
- To the slave boy example, we can respond that his knowledge was not innate, but gained through reasoning. However, an empiricist must add that this reasoning is working with analytic truths, otherwise one form of rationalism – nativism – is defeated only to be replaced by another, as follows the claim that we can acquire knowledge through reasoning alone. 
- We can also ask how we come to have knowledge of the Forms in this life. Obviously, it can’t be through sense experience. So there must be some other faculty through which – if Plato was right – we could ground and justify claims about the existence and nature of the Forms. 
- Plato thought this faculty was nous. Sense experience is about what is particular and concrete – this book, this rose. To know the Forms, we must turn towards what is abstract. Using pure reason, we move from one abstract idea to another, from one abstract truth to another. 
-

- How dow we come to have knowledge of the Forms? Obviously, it can’t be through sense experience. So there must be some other faculty which - if Plato was right - we could ground and justify claims about the existence and nature of forms.
- Plato thought this faculty was nous. Sense experience is about what is particular and concrete - this book, this rose. To know the Forms, we must turn towards what is abstract. Using pure reason, we move from one abstract idea to another, from one abstract truth to another.
- But we can object that this is no explanation of how we came to know the Forms. We can explain how physical objects cause our sensory experiences through our 5 senses: we have no similar explanation of how abstract objects such as the Forms cause abstract thoughts. 
- At this point, we should remember that that Plato supplements his theory of nous by an appeal back to nativism; the truths we discover using a priori reasoning and insight depend on the triggering of concepts that are innate.
- Nous seems obscure. But it isn’t the only model of a priori reasoning, we discussed the Descartes, God, evil demon ****. Descartes analyzed his ideas to see what it was impossible to doubt. But does Descartes a priori reasoning lead to the results he wants. For now, we’ll look just at his claim about the mind. 
- Descartes claims that ‘I’ am a thinking thing, a substance. Many philosophers have thought he means to show that I am the same thing from one moment in time to the next, a mind existing in time. 

- The same ‘I’ persists from one thought to another. But how can Descartes be certain of this? All that we experience is only a succession of thoughts. Instead of ‘I think’, Descartes should have concluded ‘There is thinking (going on)’.  
- Second, many philosophers also object to his claim that to know that his mind exists independently of his body. Just because Descartes can think of his mind existing without his body, this doesn’t mean that his mind really can exist without his body.
- Or again, just because he knows he exists, but doesn’t know if his body exists, this doesn’t mean he can exist without his body. Perhaps there is some connection between his mind and body that would make this impossible that Descartes doesn’t know about.
- Descartes has used a test of what he knows and doesn’t know as a test of what is possible. But this is not a good test, and so he hasn’t shown that minds can exist independently of bodies. 
- What does this show about using a priori intuition and demonstration? Descartes has done his best find what he thinks, using reasoning, is certain.
- His arguments are supposed to be deductive, and his premises established by rational intuition. But philosophers have still been able to point out unjustified assumptions and inferences. If intuition and demonstration do not give us knowledge, then rationalism is in trouble. 

- Friedrich Nietzsche argues that Plato’s theory of reason and the Forms is completely mistaken. Plato takes his a priori reasoning to be something that reveals the truth.
- In fact, argues Nietzsche, ‘most of a philosopher’s conscious thinking is secretly guided and channelled into particular tracks by his instincts. Behind all logic, too, and its apparent tyranny of movement there are value judgments, or to speak more clearly, physiological demands for the preservation of a particular kind of life’ (Beyond Good and Evil,§ 3)
- Plato’s entire metaphysical theory of the Forms is actually based on his desire to see good and bad as opposites: ‘The metaphysicians’ fundamental belief is the belief in the opposition of values.’ This is why they construct a theory about a world beyond this ‘lowly, deceptive’ world, a world of purity and certainty. But if we reject this opposition as fictitious, as no more than a fantasy expressing a wish, all of Plato’s reasoning will not be convincing.  
- The same goes for any other attempt to establish truth without looking closely at experience and at the role our value judgments play in influencing what we think philosophically. Nietzsche agrees with Hume about the limitations of reason, but goes further when he argues that every great philosophy is founded on the personal value judgments of the philosopher. 

Ayer's verification principle: a statement only has meaning is it is either analytic or empirically verifiable.However, the principle itself is neither analytic nor empirically veritable. 
Mathematical knowledge:
- Often held by rationalists as a good example of what we can know a prior thought reasoning alone.
- It is difficult to argue that mathematical knowledge is a posteriori. 
- If we say that 2 + 2 = 4 is just a generalisation of our experience so far, then as Hume argued, this 'matter of fact' is not certain, but only probable. But this is unimaginable (if you have 2 apples in 1 hand and 2 apples in the other hand, but only 3 apples in total?? how??)
- Empiricists can accept that mathematical knowledge is a priori, if they also argue - which they do - that it is anyatic: all mathematical knowledge is reached by developing a series of definitions.  
- But if all this is true, how are mathematical 'discovers' possible? How can we 'discover' something that is true by definition? 
- Empiricists reply that analytic knowledge doesn't need to be obvious: mathematical truths are complex, so it takes work to establish that they are true. But that does't mean they are not true by definition. 
- This reply can be difficult to believe. For example,  truths of geometry don't seem to be true by definition. 

- The fact that it takes at least 3 straight lines to enclose a space in two-dimensions seems to be a truth about the nature of space, rather than the concept of space.
- Yet it has mathematical certainty and can be proved by mathematical geometry. *** could such certainty come from sensory experience alone.
- In fact, there is more than one geometry of space. It is in classical, or Euclidean, geometry that it takes 3 straight lines to enclose a two dimensional shape.  
- But mathematics has worked out perfectly good, consistent non-Euclidean geometries in which this and other 'truths' are not true. (if you curve the two-dimensional plane, for example, the surface of the Earth, you can enclose a pace with 2 straight lines)
- So empiricist argue, geometry applied to the real world has two elements: a series of definitions, which are analytic truths; and then an a posteriori claim about which type of geometry applies to space.
- So there are geometrical truths about the nature of space, but they are not necessary - space could have been otherwise for example, non-Euclidean.
- In fact, in some cases in advanced physics, Euclidean geometry does not describe space accurately. 
- Empiricists such as Bertrand Russell argues that although mathematical truths were not analytic, they were nether the less 'logical' truths. 
- His argument depended on technical developments in logical and in mathematics. Philosophers still disagree about the success of Russell's attempt - and attempts by other philosophers since - to reduce mathematics to logic truths.
- It is fair to say that whine some attempts are promising, no reduction had been completed 

- Descartes understands knowledge in terms of what is ‘completely certain and indubitable’ (Meditation I).
- To establish this certainty, he seeks to test his beliefs by doubt. If we can doubt a belief, then it is not certain, and so it is not knowledge.
-However, Descartes takes ‘certainty’ to be a very high standard. He wants to find out what cannot be doubted, not just what it is reasonable to believe. 
- When he says that he cannot doubt that he exists, or later that God exists, what he means is that when he considers these claims carefully, he is unable not to believe them.
- Using his best, most careful judgment, he judges that it is impossible that they should be false. Knowledge is more than true belief – it must be justified. 
- Descartes argues that it must be certain. But we can object that this isn’t necessary; we can have beliefs that are justified, e.g. we have good evidence for them, but they aren’t certain. 
- So the question of this section – Is certainty confined to introspection and the tautological? – is not the question of whether knowledge is confined in this way.
- To say that it is, we must first argue that knowledge involves certainty. But we won’t discuss it here, so we put aside the question of knowledge and concentrate on certainty. 

Certainty’ can have at least two different meanings, perhaps three: 
1. It has a subjective, psychological meaning, as in ‘I feel certain that…’. This is perhaps something like a feeling, a feeling of conviction.
2. It has a logical meaning, e.g. the truth of a proposition can be certain because the proposition logically must be true.
3. And perhaps it has a third meaning somewhere between the two, viz. that a proposition cannot be doubted. This brings together the objectivity of the second meaning with the psychological nature of the first.
Which of these senses is important for our discussion? 
- The first seems irrelevant; we cannot discover what and how we know just from what people feel certain of. This is too subjective. But what we can and cannot doubt (the third meaning) is relevant.
- Now in many cases – but not all – we cannot doubt some proposition because it must be true (the second meaning). 
-To pursue the second definition further, we need to introduce a distinction that plays a big role in the debate between rationalism and empiricism: necessary and contingent truth.

- A proposition is contingent if it could be true or false; of course, it will be either true or false, but the world could have been different.  Many empirical facts are like this: it is true that you are reading this book; but you could have been doing something else. So it could have been false.There are more types of insect than there are of any other animal. This wasn’t always true, and one day it might be false again. 
- A proposition is necessary, or necessarily true, if it not only is true, but must be true (it is necessarily false if it couldn’t be true). Mathematics is usually thought to be necessary: 2 + 2 must equal 4; it is not possible (logically or perhaps mathematically possible) for 2 + 2 to equal any other number. (Of course, it is possible that the figure ‘2’ could have been used to mean the number 3. But then ‘2 + 2’ wouldn’t mean 2 + 2; it would mean 3 + 3. To test whether a proposition is true or false, in all cases, you have to keep the meanings of the words the same. If ‘2’ means 2, and ‘4’ means 4, then 2 + 2 must equal 4.) Likewise, analytic truths are necessary: if a proposition is true by definition, then it must be true.
- Historically, philosophers have also agreed that a priori knowledge is necessary and a posteriori knowledge is contingent. 
- After all, a posteriori knowledge is knowledge of how the world is, and surely the world could always have been a different way – so all propositions about the world could have been true or false. 
- Of a priori knowledge, empiricists thought it was necessary because it is analytic. Rationalists argued that the type of knowledge we gain through a priori reasoning is also necessary.

- A tautology is a statement that says the same thing twice in different words. In the context of epistemology, it is just another term for an analytic proposition. Because everyone agreed that analytic truths are necessary, then there is also no argument that they are certain. So what is tautological is certain.But can any beliefs other than beliefs about analytic truths be certain? If certainty is restricted to necessary truths and these are all analytic, then the answer is no.  But this is forgetting our third sense of ‘certainty’ – there may be beliefs that I cannot doubt, even though they are not necessarily true. The best examples are beliefs based on introspection, the observation of one’s mental states and processes.  Descartes and Hume both agreed that I cannot doubt my experiences themselves. I can doubt that I am seeing a table, but I cannot doubt that I seem to be seeing a table. Likewise, I may not know what is causing my pain, but I cannot be mistaken that I feel pain. The claims that I seem to see a table or that I am in pain are not necessarily true, but contingent.  But they can still be certain. This must be the third sense of certainty – it is impossible, for the person who has the experiences – to doubt their truth.These are the only two classes of certainty that empiricists have traditionally allowed. Hume argues that all a priori knowledge is analytic, while all knowledge of matters of fact, beyond my own mental states, involves induction, inference, and probability (see the handout on ‘Empiricism on the limits of knowledge’), and so cannot be certain.  However, rationalists argue that there are synthetic a priori truths, and these are necessarily true, and so they are certain. So whether certainty is confined to introspection and analytic truths depends on whether rationalism can be defended.

- Try to imagine what it would be like to have sensory experience but with no ability to think about it.
- Thinking about sensory experience requires concepts – at the most basic level, being able to distinguish what comes from the different senses (vision, hearing, etc.), and then being able to distinguish types of properties, e.g. colour from shape.If we couldn’t think about sensory experience, it would be completely unintelligible, no more than a confused ‘buzz’.
- For instance, and very importantly, we couldn’t tell that we were experiencing anything – i.e. objects. The idea of an object is the idea of something that is unified in some way - a colour, shape, position, and so on, going together; or even more fundamentally, something that exists in space and time.
- A ‘buzz’ doesn’t deserve the name ‘experience’. Experience is experience of – experience of objects, in fact, experience of a world of objects, i.e. objects that stand in organized relations (in space and time) to each other. How is it that our experience is intelligible in this way? We take it for granted that we see desks, hear cars, smell roses. But we shouldn’t take it for granted, and this leads to a, perhaps the, fundamental question in epistemology: how is it that we can make sense of reality, so that we have experience and not a buzz? - In Critique of Pure Reason, Immanuel Kant argued that intelligible experience – experience of a world of objects – presupposes and requires certain, very basic concepts, which he called categories.

- Knowledge is a relation between the mind and reality. Philosophers like Descartes, Locke and Hume took this relation for granted, in the form of ‘experience’. 
- For example, Locke begins his account of how we acquire concepts by saying that ‘The Senses at first let in particular Ideas.’This just takes it for granted that our minds are set up to represent the world as it really is. Kant’s great insight was not to take this for granted, but ask how this is possible.  
- In Locke, there is no real explanation here of how we can know about the world through experience. Perhaps the senses are completely misguided. 
- Descartes argues that we have the innate concept PHYSICAL OBJECT and that God, who is the source of innate concepts, guarantees that this concept applies to reality. But if his argument for God’s existence fails (which Kant thought it did), then we are left with the possibility that our innate concepts are also misguided.
- The answer, Kant thought, lay in thinking further about experience. Firstly, we know that intelligible experience is possible, because we have it.
- Intelligible experience is what we mean by ‘experience’, in the sense of a perceptual experience of something. Experience is of objects. So experience has a certain structure – it is structured by objects, and these objects exist in space and time.
- It is through experience that we gain knowledge. So what makes this structure of experience possible? If we could answer that, we would have shown why it is that we can know about reality.

- We want to know what makes the structured experience of objects possible. Kant answers that it is the possession and application of certain basic concepts, each of which contribute to the concept of an ‘object’. 
- His argument for the (twelve) concepts he lists and no others is contentious, and many philosophers think it doesn’t work. 
- What has been more influential are his arguments for each concept in turn. One argument that has been thought particularly powerful is his argument for the concept CAUSALITY.
- The argument is this (Critique of Pure Reason, B232-8). To experience the world in terms of objects involves distinguishing between the time in which our experiences occur – when we have them and in what order – from the time in which the objects exist. 
- For example, I can, at two times, look at an object from two different angles, seeing different sides of it. My perception of the object changes, and one experience follows the other in time.
- But I don’t say that the object has changed, or that there are two different objects, one of which follows the other in time – I say that the object has remained the same over time.
- Kant gives the example of looking around a house. I have a series of perceptions, changing in time, but the house remains unchanged. However, on another occasion, we say that the changes in our perceptions reflect changes in the object. 

- Kant gives the example of watching a ship sailing down a river. In this case, it is not just that my perceptions change over time, the object itself is changing (in position). 
- How is it possible that can we make the distinction between the sequence of changes in my perception and the sequence of changes in the object? Obviously, it is possible; but how?
- Kant’s answer is that in the case of looking around the house, we understand that the order of the perceptions can be changed, e.g. we could have looked at the walls top to bottom instead of bottom to top, say, without the house itself changing. 

- In other words, the order in which we have the experiences doesn’t change what we experience. When the object doesn’t change, the order of perceptions is not determined.
- In the case of the ship, the order of the perceptions cannot be different: we first see the ship upriver and then we see it downriver.
- If we saw the ship first downriver and then upriver, we would be seeing a different event – not a ship sailingdown the river, but a ship sailing up the river.
-So when the objects change, we cannot change the order of the perceptions. The order of the perceptions is determined by the object changing. - This means that we have an idea of a ‘necessary temporal order’. Without this idea we couldn’t make the distinction between perceptions that change because the object does and perceptions that change when the object stays the same. 
- This idea is that of CAUSALITY. Causality is the relation between cause and effect, and we think that effectsfollow causes; in fact, we think that effects must follow their causes.
- We say that an event c, e.g. letting go of a pen, causes another event e, the pen falling to the floor, only when e regularly follows c. 
- If pens didn’t (almost?) always fall to the floor when we let go of them, we wouldn’t say that letting go of them caused them to fall to the floor. 

- Blinking isn’t followed by the pen falling to the floor; sometimes it is, sometimes it isn’t. We don’t think blinking causes pens to fall. 
- So CAUSALITY is precisely the concept that things happen in a certain, determined order. 
- So Kant concludes that without the concept of CAUSALITY I cannot distinguish between an object changing and just my perceptions changing.
-Finally, I need this distinction to be able to experience objects at all. So without CAUSALITY, I can’t have intelligible experience. So CAUSALITY is necessary for experience to be possible. 

The most important regards the relation between the mind and the world.
- Experience, we have said, has a certain structure – it is experience of a world of objects; and this structure is made possible by certain key concepts which contribute to the ideas of an ‘object’ and of an objective world, including CAUSALITY, SUBSTANCE, UNITY and so on.
- These concepts can’t be derived from experience, because they are what make experience possible in the first place. So they are a priori; Kant says they are part of the nature of the mind.
- So we reach this conclusion: that the ‘object’-ive nature of experience is a reflection of the nature of the mind.This means that our experience of and our thoughts about everyday objects – tables, plants, and so – is not a straightforward presentation of what exists completely independently of the mind (what Kant calls ‘things-in-themselves’).
- The idea of an object doesn’t reflect the world, it reflects the mind. So everyday objects are defined by our structured experience of them.So now if we try to think of how things are, how reality is, quite independent of these a priori concepts of ours, we find we cannot.
- We cannot know what reality is completely independently of how we think about reality – which is in terms of objects.And yet we clearly don’t want to say that reality depends entirely on our minds – something exists independently of our minds, the something that produces experiences

-. But we cannot know anything about this ‘something’ – we have to think using our a priori conceptual scheme. 

- This doesn’t mean that the world of experience – the world of objects – isn’t real. Of course it is real; indeed, it is by definition ‘objective’. However, it is defined by the contribution our mind makes as well as the (unknown) contribution made by whatever is completely independent of our minds.

 We saw that Kant starts from the objection to empiricism and rationalism that it cannot explain the relation between the mind and the world that is necessary for knowledge.
- The empiricists assume that the senses ‘let in’ the world as it really is; rationalists assume that our innate concepts match it. Both assumptions are unjustified. Perhaps the way we experience or conceptualise the world is completely different from how the world is. But has Kant left us in the same position?
- He would argue that he hasn’t. He has shown how we can know about the world – the world of physical objects that we experience with the senses; we can know about it because the world as we know it isstructured by our a priori concepts.
- How things are is given by these concepts, so there is no question of a ‘match’ between our minds and how things are. 
- But then what about how things are independent of our minds? About this we can know absolutely nothing; we cannot even coherently think about it. But this is not an objection for Kant, because there is no meaningful way in which we could know about it.
- If Kant had argued just that our experience is a certain way, we could object that our concepts were a limitation to our knowledge – we weren’t able to experience the world as it really is.

- But Kant has argued that our experience must be the way it is – there is no alternative to experiencing the world as a world of objects, so there is no alternative way of experiencing ‘the world as it is’. Any alternative wouldn’t be ‘experience’ at all. 
- For example, the distinction between the temporal order of experience and the temporal order of objects is not just what makes experience of objects possible.
- It is also necessary if we are to be able to talk about experience of objects. The distinction between the temporal order of experience and the temporal order of objects is part of the general distinction between experience and the world which we experience. Without this distinction, ‘experience’ would not be ‘experience of’ anything.
- This makes our experience properly objective, the basis of knowledge of how things are. What we don’t know – how the world is completely independently of our minds – is what it is impossible to know. So there is nothing here we could know but don’t.

- These concepts, taken together, form our fundamental conceptual scheme. Kant argued that sensation is completely meaningless to us unless and until it is brought under these basic concepts. 
- Kant thought that there was only one basic conceptual scheme that could provide experience as we know it. There can be no other set of concepts which creatures like us could have.
- The conceptual scheme is necessary for experience at all; so any creature that we think has experience – intelligible experience of objects, not a confused buzz – must have these concepts. 

Suppose on one occasion, I read my horoscope and   believe the predication, although there is evidence against thinking it is write. And then this prediction turns   out to be true! Did I know it was right? It looks more like my belief is irrational. I had no reason, no evidence, no justification, for believing that prediction was true. Knowledge, then, needs some kind of  support, some reason for thinking that the proposition believed is true. Knowledge needs to be justified.

- It is not a claim about how we acquire concepts or words of propositions. Babies are not born knowing that   all bachelors are unmarried men. Yet this is a truth that clearly doesn't need testing against experience: 
  we know it is true just by knowing what it means, Of course, we first have to learn what it means, but that     is a different issue from how we check if it is true.
- However, we can also apply the distinction to concepts. An a priori concept is one that can be drives from   experience.  

- So their very experience of time was different from ours, or as some thinkers put it – time is different for them: We are thus introduced to a new principle of relativity, which holds that all observers are not led by the same physical evidence [i.e. stream of sensory experience] to the same picture of the universe, unless their linguistic backgrounds are similar, or can in some way be calibrated’ (Language, Thought and Reality, p. 55). 
-  So if people have different languages, different conceptual schemes, then they will end up with different pictures of the universe.

- But what we have said is that what is true in one scheme cannot be expressed in another. 
- In this situation, there is no disagreement over what is true – to disagree, the two schemes would have to be able to express the same proposition (e.g. ‘it is green but not blue’). But this is what they cannot do.
- We end up with the somewhat unsurprising position that in order to state something true, you must be able to state it.
- But what you can state depends on what concepts you have. However, we have not established just how different such conceptual schemes can be.
- In Development , we will look at an argument that there are a priori limits to conceptual schemes if people are able to experience the world at all.

- Hume presents a separate argument to support this claim: someone who lacks a certain type of experience also lacks a certain type of idea – showing that the ideas derive from experience. 
- Thus, a blind man does not know what colour is and a mild man cannot comprehend the motive of revenge. More generally, as human beings, we can have no ideas corresponding to the senses of aliens (if there are any). We are limited to thinking about what we can experience.

- RESPONSE: However, philosophers have objected that Chomsky hasn’t identified a form of innateknowledge. The ability to classify and construct grammatically correct sentences, even if innate, isn’t a type of knowledge. If it were knowledge, then children would have to have (non-conscious) beliefs about grammar. But this doesn’t seem right. It is better to say they have an ability, and abilities aren’t knowledge (they are know-how rather than know-that, propositional knowledge). 
- REPLY TO RESPONSE:, we can reply that if the ability to classify grammatically correct sentences is innate, then this generates innate knowledge: the child’s knowledge that ‘the cat look there on the mat’ is incorrect has not been learned from experience. So there is innate knowledge – not the ability, but the knowledge the ability enables. 

 But we can object that this is no explanation of how we come to know the Forms. We can explain how physical objects cause our sensory experiences through our five senses; we have no similar explanation of how abstract objects like the Forms cause abstract thoughts.
- At this point, we should remember that Plato supplements his theory of nous by an appeal back to nativism; the truths we discover using a priori reasoning and insight depend on the triggering of concepts that are innate. 

- Hume presents a separate argument to support this claim: someone who lacks a certain type of experience also lacks a certain type of idea – showing that the ideas derive from experience. 
- Thus, a blind man does not know what colour is and a mild man cannot comprehend the motive of revenge. More generally, as human beings, we can have no ideas corresponding to the senses of aliens (if there are any). We are limited to thinking about what we can experience.

- RESPONSE: However, philosophers have objected that Chomsky hasn’t identified a form of innateknowledge. The ability to classify and construct grammatically correct sentences, even if innate, isn’t a type of knowledge. If it were knowledge, then children would have to have (non-conscious) beliefs about grammar. But this doesn’t seem right. It is better to say they have an ability, and abilities aren’t knowledge (they are know-how rather than know-that, propositional knowledge). 
- REPLY TO RESPONSE:, we can reply that if the ability to classify grammatically correct sentences is innate, then this generates innate knowledge: the child’s knowledge that ‘the cat look there on the mat’ is incorrect has not been learned from experience. So there is innate knowledge – not the ability, but the knowledge the ability enables. 

 But we can object that this is no explanation of how we come to know the Forms. We can explain how physical objects cause our sensory experiences through our five senses; we have no similar explanation of how abstract objects like the Forms cause abstract thoughts.
- At this point, we should remember that Plato supplements his theory of nous by an appeal back to nativism; the truths we discover using a priori reasoning and insight depend on the triggering of concepts that are innate. 

- Before we become skeptical about intuition and demonstration, we should ask this: how have philosophers come up with objections to Descartes? It certainly isn’t by using sense experience! So the objections themselves use the same kind of reasoning as Descartes. 
-Only better reasoning, we hope. The objections cannot be objections to the way Descartes reasoned, only objections to the conclusions he drew. 
-Hume, however, argues that what can be established by a priori reasoning is very limited. Hume’s fork claims that there are only 2 sorts of knowledge: what we confirm through the senses (a posteriori knowledge) and what reason can demonstrate (a priori knowledge)
- But, Hume argues,  reason can only demonstrate analytic truths; there is no such thing as ‘intuition’ in how things are or what exists.