3.1.3 Reason as a source of knowledge
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What are synthetic and analytic truths?
Synthetic truths are true both because of what they mean and because of the way the world is
Analytic truths are true in virtue of meaning alone.
What is Rationalism?
The belief that not all a priori knowledge is of analytic truths (I.e. there is at least one synthetic truth that can be known a priori using intuition and deduction)
What is Innatism?
The belief that we have knowledge prior to birth
What is the paradox of knowledge in syllogism form?
P1: If you know what you’re looking for, inquiry is unnecessary
P2: If you don’t know what you’re looking for, inquiry is impossible
C: Therefore, inquiry is either unnecessary or impossible
Explain the slave boy argument
Socrates asks a slave boy to double the area of a square.
His confident first answer is that you achieve this by doubling the length of the sides.
Socrates shows him that this, in fact, creates a square four times larger than the original.
The boy then suggests extending the sides by half their length.
Socrates points out that this would turn a 2x2 square (area = 4) into a 3x3 square (area = 9).
The boy gives up and declares himself at a loss.
Socrates then guides him by means of simple step-by-step questions to the correct answer. The boy answers that one must use the diagonal of the original square as the base for the new square.
Socrates describes the boy’s knowledge as having been ‘spontaneously recovered’ and the boy as being ‘awakened into knowledge by putting questions to him’.
Socrates draws the knowledge out by cross-examination where only questions are asked and no information is given
Cross-examination = elenchus
So this method of cross examination through asking questions = Elenctic Method or Socratic Method
The process of learning by remembering = anamnesis
Socrates described himself as a ‘midwife’(in Theaetetus), who is able to draw out knowledge which exists already within the soul
Plato uses the slave boy argument to assert that there exists within our minds innate ideas, just as the slave boy has knowledge of geometry, which we can recall through the Socratic Method
He also uses the theory of anamnesis to argue that the soul is immortal
"His soul must have always possessed this knowledge [...] And if the truth of all things always existed in the soul, then the soul is immortal.’
Explain the response to the slave boy argument
Maybe the slave just used reason to work out what must be the case given certain features of lines and shapes.
It isn’t necessary to posit innate knowledge to explain how the boy can reason his way to the discovery of a geometric truth.
Explain Leibniz’s response to the slave boy argument
Leibniz wanted to develop an idea of innatism which did not rely on Plato’s concept of anamnesis.
He wished his philosophy to be ‘purged of the error of reminiscence’
Leibniz discussed the slave boy argument and came to a different conclusion:
The boy has not ‘remembered’ something that he already knew
The boy has realised that it was impossible to reach any other conclusion other than that a square with its sides being the length of the diagonal (pythagoras’ theorem: a^2 + b^2 = c^2) of the first square is double the area of said first square
This is a necessary truth
The proof discovered by the boy was true ‘in all possible worlds’ - Leibniz
Explain what is meant by necessary truths
These are truths which exist because it is impossible for them not to exist
Some truths are not necessary
We see the sun rise everyday (a specific instance)
From this we make a general truth that it rises everyday (via induction)
This truth is revealed by the senses
It is not necessary (e.g. one day the sun might stop existing)
Mathematical truths are necessary
E.g. 2+3=5
Our mind sees that this will always be the case
Even though if we add 2 apples to 3 apples 1 00000 times, you never know what will happen the 100001st time
Because our senses will only tell us about specific instances
But we know that 2+3=5 is a necessary truth
Because its necessity is revealed by reason (the application of innate principles) not the senses.
What is the syllogism for Leibniz’s idea of necessary truths?
P1: The senses only reveal instances of general truths
P2: The senses cannot reveal the necessity of a general truth
P3: Our minds can see the necessity of some general truths
C1. Our ability to see the necessity of general truth is not derived from our senses but is based on innate principles
Explain Leibniz’s alternative idea to Locke’s tabula rasa
For Leibniz, innate ideas/principles do not exist within us fully formed from birth;
Instead Our mind is like a block of marble with ‘veins’ running through it in such a way that it will readily take a specific shape
Marble doesn’t contain a fully formed statue but has the ‘inclination’/’tendency’ to take a statue’s shape when struck
We aren’t born with fully formed innate ideas but our minds are structured so that certain ideas/principles will appear when prompted by senses
Explain Locke’s argument of ‘No universal assent’ as a criticism of innatism
The case for innate ideas is supported by suggesting that there are some principles which are universal – or which everyone agrees to.
Locke argues against this
Children and idiots have no thought – not an inkling – of these principles, and that fact alone is enough to destroy the universal assent that any truth that was genuinely innate would have to have.
So children and idiots don’t have allegedly innate principles like the law of non-contradiction
He develops this point further by focusing on the mind of a newborn
This ‘differs not much from the state of a vegetable’ as it has no real perception/thought.
However, over time as the newborn has new experiences, it ‘begins to know the objects which it is most familiar with’.
Soon,after having sensations, it will have its own ideas as ‘there do not appear to be any ideas in the mind before the senses have conveyed any in.’
In other words, we only gain knowledge through our individual experiences, none of which are exactly the same as any other being and so there are no truly universal ideas and hence no innate ideas.
What is the syllogism for Locke’s argument of ‘No universal assent’?
P1: Any innate idea, x, if it exists, would be universally held.
P2: Children and idiots do not have the idea of x.
P3: If an idea is held in the mind then you must be aware of it. (his transparency argument)
C1: So x is not universally held.
C2: therefore x is not innate.
Explain the innatists response to Locke’s ‘No universal assent’ argument
Leibniz claims that children and idiots do employ innate principles in their everyday actions even if they can’t articulate these ideas in words
e.g A child knows that their pen can’t be simultaneously in their hand and in the kitchen
Also Chomsky’s universal grammar and the language acquisition device
Perhaps children and idiots have these principles but are not aware of them …
Explain Locke’s Transparency of ideas argument
Deals with the claim that children and idiots might possess innate ideas they just aren’t aware of yet
Locke argues that
If we did have innate ideas, then they must be present in our minds
We must have been conscious of them at some point
Our minds are transparent and we can perceive all the ideas they contain
If we’ve never had a certain idea/thought, how can we claim it to be ‘in’ our mind?
Explain the response to Locke’s transparency of ideas argument
maybe there are ideas ‘in’ your mind which you’ve never been conscious of
e.g. if you subconsciously ‘absorbed’ a song playing in a shop then it isn't ‘transparent’ in your mind but might still be recognisable if you heard it again. So it must be ‘in’ you
Leibniz argues in his New Essays that an innate idea could be ‘in’ your mind without you being aware of it yet - e.g. you didn’t ask yourself ‘How do I know I’m not you?’ before knowing you weren’t other people.
Knowledge that ‘I am not you’ always existed as an idea before I actually thought about it
Also Chomsky’s universal grammar and the language acquisition device
Explain Locke’s argument on the difficulty of distinguishing between innate ideas and other ideas
Locke considers the possibility of the position that some of our ideas are innate and others are gained from experience.
He argues that this is a contradictory position because we would be unable to distinguish between the innate ideas and those gained through experience.
If some ideas are innate and some are a posteriori then how can you tell them apart?
Why not claim that the idea of ‘blue’ is innate and simply becomes active once you see the colour
Explain Leibniz’s response to Locke’s challenge of distinguishing between innate ideas and other ideas
Leibniz says you can distinguish innate and non-innate ideas
Because they are true in a different way
Innate ideas are necessarily true
Even though young kids might not know many mathematical truths, once they understand it, their mind immediately recognises that they are true in all possible worlds and that they differ from truths of fact (his take on the slave boy argument)
Explain Locke’s argument of tabula rasa against innatism
John Locke put forward the theory known as empiricism and which rests on the idea that the mind of a newborn is a ‘blank slate’ or ‘tabula rasa’
Also refers to it as white paper or an empty cupboard
It follows that Everything we know about the world is derived from our experience of the world.
This means that all our knowledge is acquired a posteriori, or as a consequence of experience.
Our experience of the world is made up of our sense experiences and our experiences are of tangible things that we can see, hear, taste, touch and smell.
These tangible things are referred to as ‘empirical data’
Locke argued that knowledge comes from two types of experience:
Sense impressions
Impressions received by our minds from our senses (our sense perceptions)
e.g. smell, taste, shape, colour
Locke describes these sensations as simple and unanalysable - they can’t be broken down any further
These qualities can be grouped into primary and secondary qualities
(e.g. ‘number’, ‘shape’, ‘size’ and ‘hardness’)
Concepts/ideas
Our sense impressions are copied into ideas and concepts once being received by the mind
e.g. I can think about cheese even when i'm not in the presence of cheese
Split into simple, complex and abstract concepts/ideas
A simple concept is the idea of one specific thing - e.g the idea of red which is based off my sensation of redness (like when looking at a rose)
A complex concept is made of simple concepts - e.g. the idea of the oceans is based on the simple concepts of blue, cold, wet, etc.
An abstract concept such as beauty or justice still comes from experience. For example, we see a beautiful lake, a beautiful painting, a beautiful person, etc. and over time we abstract the common features from these experiences to form the abstract concept of beauty.
Locke claims all concepts – from the simple to the complex – are derived from experience in some way, and so are not innate.
What is the syllogism for Locke’s theory of sense impressions and concepts that can be used to attack innatism?
P1. The theory of innate ideas claims that we are born with innate ideas
P2. All of our ideas can be shown to be derived from experience (tabula rasa)
C1. The theory of innate ideas is redundant
C2. Innatism fails
Explain the support for the tabula rasa theory
Those born lacking a sense (e.g. lacking impressions of red) also lack the corresponding idea (redness)
You can’t imagine a new idea (e.g. a mountain made of gold) that isn’t ultimately derived from impressions you’ve experienced (gold + mountain)
Explain the issues with the tabula rasa theory
Relational concepts -
Concepts such as ‘sameness’ have no particular colour or taste and can’t be related to any specific impression
So is it derived from impressions?
Locke’s account of reflections as a possible response - ‘sameness’ is an example of a reflection (reflections are operations of our own mind, comparative, ‘sameness’ is an example of a relation (type of reflection) still rooted in experience as in we compare our experiences of objects to conclude they are similar/have ‘sameness’)
Concepts needed for experience
Kant argued that we experience the world as a series of objects in space and time interacting in causal ways
Because your experience has the concepts such as unity, space, time and causation already applied to it by you
Sense impressions (Kant calls them intuitions) prior to any form of conceptual ordering can't form any part of any experience
We have innate concepts that enable experience to happen
Noam Chomsky argues that our minds must have innate structures in place to learn language efficiently as children
Explain Hume’s fork
InHume’s An Enquiry Concerning Human Understanding he gives an account of knowledge in relation to reason and experience
Relations of ideas:
Concerned with mathematics, geometry and logic
Known A priori (outside of experience ie by reason)
Analytic statements (those true by virtue of meaning alone - true by definition, tautologies)
Necessary (their opposite is impossible and to deny them is a contradiction)
e.g. 2 + 3 = 5‘all bachelors are unmarried men’
Matters of fact:
Concerned with science, observations and generalisations about the world
Known A posteriori (as a result of experience)
Synthetic statements (those true by virtue of meaning and because of the way the world is)
Contingent (denying them is conceivable)
e.g. Paris is the capital of France
What does Hume’s fork suggest about the idea of innatism?
Suggests that substantial knowledge (knowledge not true by definition) cannot be generated by reason alone
Synthetic truth cannot be a priori - Direct opposition to Descartes
Synthetic truths are true both because of what they mean and because of the way the world is
Disputes rationalists who tried to use reason alone to show how the world must be
According to hume
Reason can only tell us things that are true by definition. All other ‘substantial’ knowledge must be gained through experience
Once we’ve observed the world, reason may be able to help us deduce some further elements and truths, but reason alone cannot tell us about the world
What did Noam Chomsky do?
American philosopher Chomsky examined the way children learn language and considered whether it was possible for humans to learn language based on the premise that we have no innate knowledge
If we learn language onto a blank slate then we learn to mimic or imitate the language terms that we observe being used by other people.
However, Chomsky observed that when very young children reach the point of language explosion they simply don’t have sufficient information to allow them to construct the sentences that they do.
Young children, he observed, are capable of making ‘infinitely varied’ statements
He realised that part of the human condition is the ability of humans to construct sentences in such a way that they are capable of saying things that have never been said before by anyone.
He argued that we are all born with an innate Language Acquisition Device (which is an innate ‘Universal Grammar) – or an inbuilt device which enables us to use language
He observed that an animal can acquire some form of language such that it appears to understand and obey instructions and other pieces of information, but no animal is capable of using language to express a thought.
Explain what is meant by intuition and deduction
Intuition
An intuition is a proposition we just ‘know’ to be true.
The ability to know something is true just by thinking about it
e.g. ‘I think therefore I am’ (Descartes’ cogito)
Truths reached through intuition are also described as ‘self-evident’ – they ‘just have’ to be the case.
Deduction
Deduction works alongside intuition in rational thought.
Deduction is where we reach our conclusions from intuited premises through the use of valid arguments.
The conclusion is true if the premises are true and the argument valid.
E.g. You can use deduction to deduce statement 3 from statements 1 and 2 below:
If A is true then B is true
A is true
Therefore, B is true
Explain Descartes’ notion of clear and distinct ideas
An idea is clear if
It is very bright and present to the mind
An idea is distinct if
It is sharply separated from other ideas
e.g. leg pain might be clear but isn’t distinct as you might struggle to distinguish the pain from the true cause (you might be wrong about what is causing it)
Clear and distinct ideas can be separated into 3 types
Tautologies
An idea which is true because of the definition of the words within the proposition.
self-defining statements such as ‘All bachelors are unmarried men’ and ‘Either it is raining or not raining’.
In each case the proposition is undoubtedly true and requires no reference to sense perception to reach the conclusion that it is true.
Mathematical propositions
E.g. 2 + 3 = 5.
In this case we use mathematical logic to prove the statement.
‘I think, therefore I am’.
The way we prove this statement is different from the mathematical statement, but it remains a statement that is proved in the mind alone.
Such statements are described as ‘self-evident’.
What are the criticisms of Descartes’ clear and distinct ideas?
Terms are not clear and distinct enough:
Leibniz suggested that a more detailed account of ‘clear and distinct’ is needed if these terms are to be used as criteria of truth.
Relying on a feeling is not enough.
Descartes does not give a sufficiently clear and distinct account of what is clear and distinct.
Quick generalisation:
Descartes puts the success of the cogito down to the fact that its truth can be grasped clearly and distinctly.
He then generalises this principle and claims that any belief he can conceive clearly and distinctly must also be true. But is this a valid generalisation to make?
Only internal criteria for truth:
The correspondence theory of truth suggests a belief (internal to you) is true when it corresponds to a fact (external to you).
However, Descartes claims we can tell if a belief is true using internal means alone (how clear and distinct it is).
Ryle suggests this approach is mistaken - a bit like working out if you have scored a goal just by checking how well you kicked the ball (not by seeing whether it goes in).
Explain Descartes’ methodological doubt
This involves doubting absolutely anything capable of being doubted (everything which is not ‘presented to my mind so clearly and distinctly as to exclude all grounds of doubt’)
Next simplify the problem, dividing it into as many parts as possible, as smallest parts as possible until we reach logic (logical atomism)
This approach led Descartes to ‘the first principle of the philosophy of which I was in search’ ,‘Cogito, ergo sum’ - ‘I think, therefore I am’.
Explain Descartes’ three waves of doubt
The argument from illusion/sense
Descartes recognises that sometimes our senses are deceived.
Close to the notion of the ‘veil of perception’
The veil of perception means that we have reasons to doubt our experiences of the world.
The argument from illusion puts forward the claim that the world of our perceptions is not necessarily the world as it is.
Descartes was fully aware that our senses can be deceived (he gave examples of the confused conclusions we reach when objects are very small or a long way from us)
So we have reasons for doubting the apparent information we receive from our senses.
The argument from dreaming
There is no clear and distinct method whereby we can differentiate between being awake and dreaming.
I cannot, with absolute certainty, explain whether I am awake or dreaming.
Therefore, I have grounds for doubt.
The Evil Demon:
In his third wave of doubt Descartes discusses whether it’s possible that our entire perception of the world is an illusion, created by an ‘evil demon’:
I will suppose therefore that not God, who is supremely good and the source of truth, but rather some malicious demon of the utmost power and cunning has employed all his energies in order to deceive me.
I shall think that the sky, the air, the earth, colours, shapes, sounds and all external things are merely the delusions of dreams which he has devised to ensnare my judgement. I shall consider myself as not having hands or eyes, or flesh, or blood or senses, but as falsely believing that I have all these things.
Explain Descartes’ cogito
Using his Cartesian method/methodological doubt, Descartes reaches the cogito as a piece of certain, clear and distinct knowledge, produced by reason alone
‘So after considering everything very thoroughly, I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.’ Descartes, Meditations, Meditation 2
Through doubting all that could be doubted, he realised his existence as a doubting thing
Even if there is a demon deceiving him, there must be something for the demon to deceive in the first place!
If i can doubt that one is awake then something is doing the doubting and so i exist
If I can doubt my sense experiences, then something is doubting and that thing which is doubting could only be my mind.
It is impossible that I don’t exist and so my existence (at least as a thinking thing) is necessary.
The term is translated into Latin as ‘Cogito, ergo sum’ and the sentence and the ideas that underpin it are referred to with the simple term ‘The Cogito’.
Is Descartes’ cogito deductive or intuitive?
Could be presented as a deductive argument
P1: I am thinking
(P2: all thinking things exist)
C: Therefore I exist
But Descartes explicitly denies that it is a deduction
Instead he claims a simple intuition of his mind shows it to him as self evident
It must be a simple intuition in as if a demon is deceiving him, this could affect the validity of his memory and thus the validity of deductive reasoning
However, surely the demon cannot be interfering with his rational thought/deductive reasoning as it requires rational thought/deductive reasoning to doubt the validity of your deductions
So maybe it is a deduction
Is Descartes cogito a transcendental argument?
Transcendental arguments attempt to transcend doubt by asserting that a certain feature is a precondition for doubt to exist
If so, you cannot doubt you exist as you must exist in order to doubt
Explain George Lichtenberg’s response to Descartes’ cogito
Criticism concerns the link Descartes makes between the statements ‘I think’ and ‘I am’.
The link Descartes makes implies that ‘I’ am a thinking thing and that the ‘I’ is the same thing whenever ‘I’ think.
Lichtenberg suggests that Descartes would have been more certain if he had revised his statement to ‘I am thinking, therefore (at this moment) I am existing’.
Explain Hume’s response to Descartes cogito
Develops Lichtenberg’s criticism
Argues that we cannot confirm that we are the same mental substance existing over time.
I may be a ‘thinking thing’ whenever I am thinking, but I cannot confirm that I am always the same thinking thing.
He supports this argument through the claim that our perceptions of things continually change.
Explain Descartes’ response to the criticisms of his cogito
He argued that it is a matter of intuitive certainty that thoughts require a thinker.
So he has done enough to verify his own existence when he is thinking
but some philosophers argue that he has not done enough to confirm his continuous (or enduring) existence.
Explain Bertrand Russell’s response to Descartes’ response to the criticisms of the cogito
When I look at my table and see a certain brown colour, what is quite certain at once is not ‘I am seeing a brown colour’; but rather, ‘a brown colour is being seen’. This of course involves something (or somebody) which (or who) sees the brown colour; but it does not of itself involve that more or less permanent person whom we call ‘I’.
Essentially, when I look at a table its more obvious that the table is being seen than that I am the thing doing the seeing
So with existence, it is a matter of intuitive certainty that my thoughts require a thinker but NOT that I am the thinker of my thoughts
Explain Descartes’ trademark argument
The trademark argument is an a priori argument for the existence of God
Descartes argued that there are three types, or degrees, of reality with each type being ‘more real’ than the previous type.
The first type is Modes. Nowadays philosophers use the term ‘Properties’. Modes are ‘less real’ than the next type of reality;
Modes depend upon finite substance for their existence.
In turn the ‘most real’ thing is called Infinite Substance.
Modes -
the property of a substance and so cannot exist independently of a substance
E.g. the mode of a brown table is its brownness
Substances -
e.g. when looking at a brown table, the table is the substance
The brownness of the table cannot exist independently of the finite substances of the table. That’s why the mode is dependent on the finite substance.
A finite substance can cause a property to exist, it can’t work the other way round.
E.g. it is the existence of a table which causes its bowness to exist not the brownness of the table which causes the table itself to exist
This hierarchical model continues to operate upwards, and so, just as the mode is dependent upon the finite substance for its existence, so a finite substance is dependent on infinite substance (or God) for its existence.
whilst people are clearly finite substances,we have in our minds the idea of an infinite substance (the idea of God)
Because of the hierarchical scale he has put forward, it is impossible that a finite substance could have put the idea of the infinite substance into the mind of a finite substance.
It must, therefore, have come from an infinite substance, or God.
So it’s simply impossible for a finite human to have come up with the idea of an infinite God.
What is the syllogism for Descartes’ trademark argument?
P1: Ideas must have a cause.
P2:A cause must be at least as perfect as its effect.
P3: I have a clear and distinct idea of a perfect being - God
C1: So something at least as perfect as the idea of God must have caused it.
P4. I cannot have been the cause (as I am an imperfect being)
P5. Only a perfect being - God can have caused this idea
C2: God exists
Explain the criticisms of the causal principle
Descartes thought that There must be at least as much reality in the efficient and total cause as in the effect of that cause.’ was a self-evident truth
Whilst its true in the physical world (similar to the first law of thermodynamics) it might not be true in the world of ideas
e.g. our minds can easily create better versions of real objects
Our ideas don't need to be caused by something with as much or more ‘reality’
Also
The Theory of Evolution demonstrates that effects can surpass causes.
John Cottingham explains how ingredients of a cake (less great) can create a cake (greater)
BUT
Without the causal principle
We may have been created/sustained by a less than perfect being or something like a process of evolution
Explain the empiricist criticisms of Descartes’ argument for the external world (candle wax)
It relies on a priori knowledge of the essence of objects to find synthetic truths so empiricists don’t like it
Locke’s proofs against innatism and tabula rasa highlight this
Descartes’ knowledge of the candle wax could only be ‘a case of vision and touch and imagination’ as all synthetic knowledge has its roots in our own experiences.
He responds with his resemblance stuff
Berkeley responds with idealism
Hume's fork suggests that substantial knowledge (knowledge not true by definition) cannot be generated by reason alone
So we can’t prove the external world exists based on intuition and deduction
Veil of perception still leaves possibility of solipsism
According to Hume, anything that can be thought of as existing can also be thought of as not existing as all statements regarding the existence of something (e.g. the external world exists) are either true or false.
So there must be a method for verifying or falsifying the proposition that the external world exists.
Hume points out that the only epistemological method for doing so is a posteriori scientific method.
We cannot decide whether or not the external world (or God) exists by analysing the external world and so Descartes cannot determine whether candle wax exists mind-independently by analysing said candle wax.
What is the syllogism for Descartes’ contingency argument?
Here Descartes argues that his own existence is enough to prove there is a God.
His argument can be presented as follows;
P1. The cause of my existence as a thinking thing must be a) myself, b) I have always existed, c) my parents, or d) God
P2. I cannot have caused myself to exist for then I would have created myself perfect
P3. Neither have I always existed, for then I would be aware of this
P4. My parents may be the cause of my physical existence, but not of me as a thinking mind
C1. By elimination therefore, only God could have created me
Explain the criticism of Descartes contingency argument
Is it possible that we could have been created by a less then perfect being?
Could we not have been created by another conscious being less great than God - perhaps an evil scientist, an angel, or even a process of evolution?
Why must our author be either ourselves, our parents, or a perfect being (God)?
After all, these options are not exhaustive (not the only ones)
Explain the empiricist response that the contingency argument is not a priori
The argument starts from a state of affairs in the world and attempts to deduce the cause.
In this way they both resemble abductive arguments, but by allegedly eliminating all other possibilities - they attempt to ‘deduce’ the only possible cause.
Because they start from observations about how the world is, they should be classed as a posteriori.
Hume would argue that the reliance on the causal principle would undermine their status as deductions, as cause and effects are inductive generalisations.
Explain Descartes’ sensations argument
Argues that his sensations of objects cannot come from within him and must be caused by the external world
He proves sensations cannot come from him
P1: The will is part of my essence
P2: Sensations are not subject to my will
C: Sensations come from outside of me
Another argument:
My nature/essence is unextended
P2: Sensations are ideas of extended things
P3: the idea of something extended cannot come from something unextended (causal principle)
C: Sensations must come from outside of me
Having proved they don’t come from him, he proves the originate from matter
P1: Sensation must either come from God or matter
P2: I have a strong natural inclination to believe they come from matter
P3: If they came from God, God would be a deceiver as my strong natural inclination to believe they come from matter would be a deception
P4: God is not a deceiver
C: Sensation originates in matter
Explain the criticisms of Descartes’ sensations argument
Maybe sensations come from a part of me which im not conscious of
Dreams are also not subject to our will but they come from within us
According to Descartes that ‘There must be at least as much reality in the efficient and total cause as in the effect of that cause.’ is self evident
This may be true in terms of the physical world but how does it apply to the world of ideas?
Our minds can easily make better versions of real objects
Hume argued our idea of God is derived from considering virtues in other people and augmenting them without limit
Isn’t even really true in the physical world
A racehorse could be a faster runner than either of its parents and Darwin’s theory of Evolution can also be used to demonstrate that over time a more ‘perfect’ being can evolve from one that is less perfect.
Are we inclined to believe that sensations come from matter?
Berkeley isn’t - idealism
So God isn’t deceiving Berkely?
God might not exist
Proof of the external world relies on the existence of God (his proofs for which are attacked by empiricists)
It's a crap proof
Locke + Russel’s arguments are simpler
Explain Leibniz’s argument for the existence of the universe
P1 - Everything that exists has an explanation of its existence, either in the necessity of its nature or an external cause
P2 - If the universe has an explanation for its existence, that explanation is God
P3 - The universe exists
C1 - The explanation of the universe’s existence is God
The universe exists contingently:
The only adequate explanation for the existence of a contingent universe, is that it rests on the existence of a non-contingent being, it is something that cannot not exist
It follows that the cause of the universe cannot be something that is part of the universe, it must be non-physical and immaterial - beyond space and time.
Explain the part of Descartes’ sensations argument which says that our sensations cannot come from ourselves using the involuntary nature of sensations
If the cause of his sensations were his own mind, those perceptual experiences would be voluntary/under his control
But sensations are involuntary
e.g. when I touch a flame, I cannot choose to not feel pain
So sensations cannot come from Descartes and must have a cause external to him
P1: The will is part of my essence
P2: Sensations are not subject to my will
C1: Sensations come from outside of me
Explain the part of Descartes’ sensations argument which relies on the causal adequacy principle
P1: My nature/essence is unextended
P2: Sensations are ideas of extended things
P3: the idea of something extended cannot come from something unextended (causal adequacy principle)
C: Sensations must come from outside of me
Descartes illustrates P2 by using the example of candle wax;
Candle wax has physical properties - the taste of honey (beeswax), the scent of flowers, a certain colour, shape and size and upon rapping it with one's knuckle, one hears a knocking sound.
When melted, all these properties change
So our perception of things in the external world don’t necessarily give us accurate information about the objects in the world (hence the need to doubt what can be doubted)
After stripping the wax of its physical features we can still recognise it to be candle wax
This is because we have intuitive knowledge of the wax’s essence which remains unchanged even when the object changes
We have knowledge of ‘something extended, flexible and changeable’.
Extended as its size increases upon melting and increases further upon boiling- this can occur more than we can possibly imagine
Flexible and changeable as it can go through more changes than can be depicted in the imagination
So we have a clear and distinct idea of physical substances as having extension and being changeable
Explain how Descartes proves that our sensations originate from matter since proving our sensations don’t come from ourselves
As Descartes’ perceptions don’t come from him, they must either come from God or matter
Given that:
Descartes has a strong natural inclination to believe they come from matte
God exists (proven by other arguments)
And God is not a deceiver (intuition),
He concludes that sensations must come from matter in the external world
Syllogism;
P1: Sensation must either come from God or matter
P2: I have a strong natural inclination to believe they come from matter
P3: If they came from God, God would be a deceiver as my strong natural inclination to believe they come from matter would be a deception
P4: God is not a deceiver
C: Sensation originates in matter
What is the syllogism for Descartes’ sensations argument?
1a and 1b produce the same argument
Part 1a:
P1: The will is part of my essence
P2: Sensations are not subject to my will
C1: Sensations come from outside of me
Part 1b:
P1: My nature/essence is unextended
P2: Sensations are ideas of extended things
P3: the idea of something extended cannot come from something unextended (causal adequacy principle)
C1: Sensations must come from outside of me
Part 2:
P4: Sensation must either come from God or matter
P5: I have a strong natural inclination to believe they come from matter
P6: If they came from God, God would be a deceiver as my strong natural inclination to believe they come from matter would be a deception
P7: God is not a deceiver
C3: Sensation originates in matter
Explain Descartes’ ontological argument
God = a supremely perfect being
Descartes asks if it's possible to separate the existence of a supremely perfect being from this God’s essence
He concludes that it isn’t
In the same way that a mountain is inseparable from the idea of a valley
A triangle is inseparable from the idea of internal angles adding up to 180°
God is inseparable from existence
He argues that it is self-evident that the property of existence is contained in the nature of God, just as the property of internal angles adding to 180 degrees is contained in the nature of a triangle.
Therefore God’s existence is self-evident.
BUT
Just because one cannot conceive of a mountain without a valley, doesn’t mean mountains or valleys actually exist
So why is God different?
God is supremely perfect and existence is an absolute perfection
Plus Descartes’ can’t conceive of God not existing
So existence is part of the concept of God
What is the syllogism for Descartes’ ontological argument?
P1: I have an idea of God (a supremely perfect being)
P2: A supremely perfect being must have all perfections
P3: Existence is a perfection
C: Therefore God exists
Premise 1 is true as the idea of God being supremely perfect is clear and distinct
I must have the idea of a supremely perfect being because I possess the idea of perfection
FOR EXAMPLE…In trying to think of a chiliagon (a 1,000 sided shape) we can only construct a ‘confused representation’ which is no different to when we picture a myriad (a 10,000 sided shape)
Despite the confusion, our minds clearly understand the difference between a 1,000 and a 10,000 sided shape - this is a clear and distinct idea
The causal adequacy principle states that ‘There must be at least as much reality in the efficient and total cause as in the effect of that cause.’
Therefore, my perfect idea could only have come from a supremely perfect being
So i have the idea of a supremely perfect being (God)
Premise 2 is true as without all perfections, God would not be supremely perfect.
Premise 3 is reached by Descartes as existence in reality is better than non-existence
This is illustrated by Descartes’ concepts of formal reality and representational reality.
Formal reality is the physical, external world.
Some things, such as horses, exist in the formal reality. Some things, such as unicorns, do not exist in the formal reality.
Instead, Descartes says that when one has an idea of something which only exists in one’s mind then that idea is part of ‘Representational Reality’.
He argues that things existing in formal reality are ‘more perfect’ than those existing in representational reality, a claim which appears self-evident.
However, given the nature of perfection as an absolute term, anything which is ‘more perfect’ than something else is by definition a perfection.
Hence why Descartes concludes that existence is a perfection and so premise 3 is true.
Explain how Descartes proves God’s existence through arguing that existence is part of the definition of God
Descartes proves God’s existence through arguing that existence is part of the definition of God.
So existence is a predicate and a necessary part of God
Similarly the predicate of internal angles adding up to 180° is a necessary part of the concept of triangle
So stating that ‘God exists’ is a tautology as it could be written ‘God who exists, exists’.
The opposite, ‘God does not exist’ could be written ‘God, who exists, does not exist’.
Therefore, God’s existence is necessary and proved by Descartes as God’s non-existence is contradictory.