reason and experience: rationalism

Explain Descartes' argument and how this challenges Hume.

Descartes argues that we can't trust sense experience alone, as it is possible, for example, that all of our sensory experiences are being produced by an evil demon who is trying to deceive us, therefore we can't be sure of sensory experiences, meaning that it is more rational to establish everything using a priori reasoning. This challenges Hume, who argues that sense experience is the basis of knowledge, because, as Descartes states, how can we be certain that sense experience isn't deceiving us? Descartes argues that we can't. Therefore, he argues that the only thing he can be sure of is that he thinks - he can't doubt this, because even if he were to doubt, this would be a type of thinking in itself. Also, even if the evil demon were to force him to doubt his ability to think, he would still be thinking. Therefore, this is the only one thing Descartes can be sure of, and he actually reaches this conclusion using pure reasoning and rational intuition, which further supports his argument that knowledge can only be established using a priori reasoning.

Explain Descartes' argument that the mind can exist without the body.

Descartes argues that, because we can't trust sense experience alone, as a result we can doubt we have a body. He argued that this is because he only believes he has a body because of sense experience, but he can't trust his sense experience because a demon could be deceiving him. However, one thing he can know is that he can 'think' and the fact that he thinks must mean he exists, thus he knows he exists, but he doesn't know for certain that he has a body. Therefore, he concluded (through a priori intuition and demonstration), that it is possible to exist without a body.

Explain Descartes' theory of how we can know the physical world exists.

Descartes argues that, ultimately, the physical world exists because God exists - he justifies the existence of God by arguing that God is perfect by definition, which means that can't be a deceiver, therefore he exists. Thus, if God exists then there must be an external world. However, we don't know this through sense experience (which Descartes says we can't fully trust), but through a priori reasoning and demonstration.

Explain the claim that there are a number of different conceptual schemes. (rationalism?)

Some philosophers argue that we don't all have the same concepts, but rather that different people have different sets of concepts or what are called 'conceptual schemes'. The theory states, that first of all, the data comes into the senses, and then we must interpret this data by using a set of concepts. It is argued that different people apply different conceptual schemes (i.e. they would have different interpretations of data from the senses). To support this idea is the Sapir-Whorf hypothesis, whereby a difference in language was analysed - they realised, while working with Hopi Indians, that the way they talked about the concept of time was untranslatable to English. It was then argued that language is a reflection of how people think and of their concepts, which supports the conclusion that their very experience of time was different from ours. Therefore, the theory concludes that if people have different languages and different conceptual schemes, this means that they have a different view of the universe.


Explain Chomsky's 'poverty of stimulus' argument.

Chomsky argues that, because children learn linguistic grammar so fast and from very poor information, that it must be innate - this is because, for it to be derived from sense experience, it would require memory, induction from examples and inference to grammatical rules. He argued that children learn grammatical rules subconsciously through being able to construct and identify grammatically correct sentences. To support his theory, he states that children, firstly, can learn grammar on the basis of very few examples, secondly, that many of these examples are presented ungrammatically, as we often speak in incomplete, interrupted sentences, and lastly, that mistakes children make in terms of their grammar often go uncorrected. All of these points would make it more difficult for children to learn proper grammar, however, as Chomsky argues, children appear to learn grammar naturally, thus they can't be learning language from experience. Therefore, Chomsky argues, exposure to language triggers innate knowledge of grammar.


Explain the nativist theory of experience triggering innate ideas.

Nativists claim that the definition of an 'innate' idea is not one we know from birth (as Locke defined it), but rather, that we have innate ideas which are triggered by experience. This explains why there are ideas which children don't know precisely from birth - because they haven't yet had the experience needed to make the ideas conscious. An example of this occurs in the study of animal behaviour - some baby birds only need to hear a little bit of its species' birdsong to be able to sing it itself - this shows that with very little sense experience (hearing a little bit of the birdsong) triggered the birds innate knowledge of it, thus supporting the nativist claim. It is also backed up by Chomsky who claimed that children learn grammar far too quickly for it to have been learned through mere sense experience; thus, grammar must be innate, as nothing else would explain how children learn so quickly/naturally.

However, it is argued by some philosophers that Chomsky's theory hasn't justified an innate knowledge, but rather an innate ability. It is argued that the ability to construct and classify grammar correctly isn't a type of knowledge, because if it were, then children would have beliefs about grammar, which is not true. What seems right is that children have the ability, thus, Chomsky isn't arguing that we have innate knowledge, weakening his argument. However, it is argued that an innate ability to construct and classify grammar correctly would generate innate knowledge, but still (indirectly) supports the argument that ideas don't come from sense experience.

Explain Plato's idea of the Forms.

Plato emphasised the distinction between what is real and what is not in regards to how we gain knowledge. He argued that world around us, which we see and experience, is not the 'real' world. This is because what is real is perfect, and because the world around us is always changing, it isn't perfect, therefore it isn't real. He refers to the world around us as the 'world of appearances'; it is fake.

To contrast with his idea of an illusionary world, Plato called the real, unchanging world, the world of 'Forms'. A Form of something is what Plato referred to as essentially being the perfect version of something. For example, the Form of a chair is what would be considered the perfect chair. Whereas, in the material world (the world of appearances), a chair that we see in every day life is imperfect, because it is only a reflection of the Form of a perfect chair.

Plato believed what exists is two separate worlds (the world of Forms and the world of appearances), therefore he is a dualist. He argued that, in order to gain access to knowledge of the Forms, we can't rely on sense experience because it is is material/imperfect, thus we can't acquire knowledge this way. As a result, he argued that to gain full access to knowledge of the Forms we must use reason and intellect. However, Plato argues, we can still access some innate knowledge of the Forms as our 'soul' has experienced them in a past life, thus how reflections of them are known to us.

Compare and contrast Hume's and Plato's theories of how we acquire abstract ideas.

Hume argued that we gain 'impressions' through sense experience - this is divided into impressions of sensation, which are derived from sense experience (e.g. seeing a car) and impressions of reflection, which are derived from experience of our mind (e.g. feelings emotions). From this, Hume claimed that ideas are 'faint copies' of impressions - for example, actually hearing a song is different from thinking of the memory of that song - the latter is weaker; fainter.  Thus, we acquire ideas by copying from impressions. This is an empiricist point of view, as Hume is arguing that we acquire ideas through sense experience.

Plato claimed that we know ideas innately because of our souls experience of the world of Forms in the past life. He believed that we know the abstract idea of 'equality' because we knew of the form of equality before birth. Therefore, Plato denies Hume's argument that ideas are obtained from sense experience, and that ideas are known from/before birth.

Compare and contrast the ways in which sense experience and abstract reasoning might give us knowledge. 

Plato argues that we can use sense experience of beautiful objects to compare what it is exactly is that all of these objects share, and from this we can use abstract reasoning to consider what the Form of beauty truly is. For example, the concept of beauty: through sense experience we can recognise what is beautiful, but it isn't immediately apparent what attributes these objects share. Plato thought we could use abstract reasoning to gain knowledge of the Forms by using our sense experience as a base for further exploration of what the concept truly is in the 'real' reality.

Descartes' thought experiment in 'Meditations' is an example of gaining knowledge through abstract reasoning alone, with no help from sense experience. He supposed that it is a possibility that our sense experience is completely false and misleading (his explanation was that it could be supplied to us by an evil demon). With this in mind, he used pure a priori reasoning to reach the conclusion that the mind exists, and from this he ultimately concludes that the world around us must actually exist as God would not deceive us. Therefore, Descartes' theory is slightly different from Plato's as it disregards sense experience as a factor in gaining knowledge about the world.

At their core, the aforementioned theories state that we can have a priori knowledge about the world beyond the analytic. This is denied by empiricism, and Hume and Locke's theory of how we gain knowledge places a much bigger emphasis on the role of sense experience. Using beauty as an example again, they state that we come to know the concept of beauty through abstracting from our experience of objects that we believe are beautiful to come to know the complex concept of beauty. This differs from Plato's theory as Hume and Locke believe that complex concepts, like beauty, are made up of combinations of simple concepts. Plato thought that there is a Form of beauty which exists independently of all the things that are beautiful.

Explain Nietzsche's criticism of Plato.

Nietzsche primarily criticises Plato, who says that his a priori reasoning reveals the truth. Nietzsche said that at the foundation of reason is a desire to see the world in a particular way. Plato wishes to see good and bad as opposites, with our 'lowly, deceptive' world secondary to the perfect world of certainty and purity. These value judgements guide the way a philosopher reasons about the world. Nietzsche said that in order to establish truth about the world we must pay attention to both our experience and our individual value judgements, in particular the way they influence how they think philosophically. Otherwise, our theories will simply be fantasies expressing a wish that is grounded within our own preferences, and is thus not truth.

Explain Ayer's verification principle.

Ayer was an empiricist who developed Hume's empiricist theory of knowledge. He developed the theory of 'logical positivism' which built on the traditional empiricist rejection of the possibility of synthetic (knowledge about the way the world is), a priori (doesn't require sense experience to be known) knowledge.

Ayer argued that a statement is only meaningful if it is analytic or empirically verifiable, otherwise it is non-sensical. By empirically verifiable, he means whether there is empirical evidence that goes towards establishing whether a statement is true or false; is it verifiable by observation or experience, rather than theory or pure logic. For example, the statement 'the moon is made out of green cheese' can be checked to see that it's false through scientific investigation. The statement 'the universe has 600 trillion planets' can be scientifically investigated, however, through principle, rather than through practice. However, Ayer stated the verification of a statement is not the same as proof of a statement, rather, it recognises whether a statement is more, or less probable, not that it is certain.

A flaw of logical positivism is that the claim that 'a statement is only meaningful if it is analytic or empirically verifiable', as a statement itself, is meaningless (according to the theory itself). This is because it is neither analytic, or can be verified empirically, thus making it a contradiction of the theory itself and therefore branding it unconvincing. Ayer stated that the definition is not supposed to be a verifiable hypothesis like a scientific statement is. He provided arguments as to why it is a good definition, but if we can dismiss these arguments then the definition itself becomes inaccurate.

One criticism of Ayer's principle of verification is that it supposes that all meaningful statements must make statements about the world. It is possible to say that talk of God or moral values are statements about the world, but it seems more accurate to say that they are not to do with the world at all as there is no possibility that we can experience them through sense experience in this life. This doesn't necessarily mean that they are meaningless- it means that they are making a different type of claim that does not immediately relate to the world around us.


Discuss the claim that all mathematical propositions are analytical.

Both rationalists and empiricists accept the claim that mathematical knowledge is a priori, as it seems wrong to say that it is simply a generalisation based on our experience arrived at through inductive, probability based reasoning. The debate is thus whether mathematical knowledge is analytic or synthetic, as if it is synthetic then it will bring down the empiricist theory that all a priori knowledge is analytic.

Therefore, empiricists claim that all mathematical knowledge is a series of definitions. For example, 2+2=4 involves definitions for 'two', 'addition', 'equality' and 'four'. When we know these definitions we can say that the formula is certain to follow from them- thus they are analytic. Rationalists can object by saying that we make discoveries in the field of maths, and its hard to see how this happens if it is only a series of definitions. However, these definitions do not have to be simple, and their complexity means that they can take a very long time to discover. Therefore, it could be argued that the empiricist theory that mathematical knowledge is analytic has more merit.