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Arguments based on reason - Coggle Diagram
Arguments based on reason
Anselm's ontological argument
Anselm uses an
a priori argument
, which is based on reason and logic alone
Anselm starts with a definition of God - God is 'that than which nothing greater can be conceived' - God is the greatest possible being
Anselm believed that things can exist in our mind (or understanding), but to exist in reality is much greater
Anselm uses the example of a painter who has the idea of a painting in his mind, but the painting is greater once it has been painted because it now exists in reality as well as in the mind of the painter
It is therefore greater to exist in both the mind and in reality, than in the mind alone - anything that really exists is greater than things that only exist in the mind or understanding
Anselm says that the 'fool' (the atheist from the psalms) would agree with his definition of God - 'that than which nothing greater can be conceived' - so therefore has an understanding of God in his mind, however the 'fool' disagrees that God exists in reality
Anselm argues that there is a universal understanding of God, even if people don't accept that God exists
As everyone has an understanding of God, God cannot just exist in the mind alone because then there would be a greater being that exists (in reality), which contradicts with the definition of God as the greatest being conceivable
Therefore God must exist both in the mind and in reality
Anselm argues that the 'fool' fails to believe only because he hasn't considered the true definition of God - once he accepts Anselm's definition of God, then he has to accept that God exists
Strengths
Most people agree with the definition of God that Anselm uses - if there is a God, God would be the greatest possible conceivable being
Anselm's argument is a priori because it is based on logic and reasoning alone - like other rationalist arguments, we can argue that the senses deceive so it is better to rely on reason
Following the premises of the argument, God has to exist because he is the greatest being conceivable, so must exist in both mind and reality - it is valid reasoning to say that existence in mind and reality is greater than existence in mind alone, so the argument works
Weaknesses
Is it possible to come up with a definition of God? It is not so easy to define something of which we have no knowledge or that is not physical
A priori arguments can also use invalid logic, it may be better to use empirically based a posteriori argument eg design arguments, to prove the existence of God - at least then we have some evidence to use
We can disagree with Anselm's reasoning and deny the premises - eg we can argue that it is better to exist in the mind alone as we can imagine things that are otherwise impossible, such as flying carpets
Hume
- "We cannot define something into existence, even if it has all the perfections we can imagine"
Gaunilo's criticisms
Although Gaunilo also believed in God, he criticised Anselm's ontological argument because he disagreed with its use of logic and reasoning
Gaunilo argues that using Anselm's logic, having an understanding of something in your mind must mean that it also exists in reality - he argues that this is a false assumption and does not have to be so
Gaunilo's island
Gaunilo says to imagine the greatest conceivable, but lost, island somewhere in the ocean - it has all 'riches and delicacies', more so than any other island
If you were told about the island you would be able to imagine it - it would exist in your mind
Anselm claims that anything that exists in reality is greater than things that exist in the mind alone - so any island that actually exists is greater than the imaginary perfect island
But using Anselm's reasoning, it is greater to exist in the mind and in reality than in the mind alone, and because this is greatest possible island, the 'perfect island' must really exist - however the island is only imaginary and does not actually exist
Gaunilo also criticises Anselm's use of an argument that relies on reasoning alone (a priori) because it is God that we are trying to prove - it is easier to have an understanding of a man or an island because we have seen these things, but we cannot claim to understand 'God' with any certainty
Gaunilo accuses Anselm of poor reasoning because simply imagining something could bring anything into existence - just because we understand something in our minds, it does not follow that the 'something' must really exist
Gaunilo's other points:
We have plenty of unreal objects in our minds - this is perfectly usual
We may even believe something unreal that someone tells us, but this still does not make it real - eg we may believe gossip, but this does not make it real
The analogy of the painter does not work because there is a real difference between the initial idea and the final product
We do not necessarily all have a common understanding of God - a being greater than all other beings might be different for different people
You can never fully understand something from description alone, different people create different pictures in their minds when the same words are spoken
You cannot define something into existence
We are fully aware of our own existence but can also think of our non-existence, why shouldn't it be the same with God? - we can imagine God's non-existence as much as we can imagine God's existence
Anselm's response (second formulation)
Anselm replied to Gaunilo's criticisms by reaffirming his initial definition of God as being the only being that cannot not exist
Anselm said that the moment you decide that there could be a being that which nothing greater can be thought of, you have placed it in your mind and this is what God is - it becomes a contradiction to say that there is a greatest possible being and that this might not exist - Anselm's point is that God is a special case
Anselm accuses Gaunilo of misplacing his logic - Anselm was not talking about any object when he made his points, he was discussing God, a
necessary being
, the greatest possible being - the island is something contingent, unlike God
Anselm argues that in other matters we say the best possible version of those matters are things we attribute to God - eg when thinking about good, we attribute perfect goodness to God
Strengths
It is possible to imagine something in your mind, but it does not have to exist in reality - eg Gaunilo understands what the greatest island would be like but it does not mean that it has to exist
Anselm is defining things into existence - it is possible to have a definition of something that exists only in the imagination eg a unicorn
B. Russell
suggested that existence is only meaningful if it refers to an 'instance' of something - eg we see an 'instance' of cows but not of unicorns
Weaknesses
Plantinga
supports Anselm against Gaunilo, he states that an island has no intrinsic maxim - it can always be improved (eg by adding more palm trees). However God has an intrinsic maxim - he is the greatest conceivable being and cannot be any greater, therefore God exists
Anselm's argument is how an a priori argument works - if you agree with the original definition, that God is 'that than which nothing greater can be conceived', then the rest of the premises and the conclusion follow on
Both Gaunilo and Russell imply the need for empirical evidence to prove existence - but arguments that use empirical evidence such as those from observation, also have problems
Kant's criticisms
Kant criticised the general approach of ontological arguments, particularly Descartes' version, but his criticisms can be used against Anselm too
Objection 1
Kant begins by supposing that it is true that existence is part of what it means for God to be perfect - Kant uses the example of a triangle, we know that having three angles is part of what it means for a triangle to be a triangle
Kant says that this example comes from a 'judgement' and not from the triangle and its existence
However a judgement is not the same as the absolute necessity of something
The triangle therefore only has three angles
if
the triangle exists in the first place
For Kant, ontological arguments are bad logic because they make us suppose that if we justify God's perfection as including existence we are assuming that God exists - it is circular logic
He argues we can make up an object and define it in any number of ways, but this does not make the object exist in reality, even though the definition will continue to be true
Both Anselm and Descartes claim it is a contradiction to say that God does not exist, however Kant argues something cannot exist by definition - you must go outside of a concept to find external, synthetic evidence to prove its existence
Objection 2
Kant's second objective is about the nature of existence as a predicate, he does not believe that existence is a
determining predicate
- a description that adds something to the understanding about the subject
Kant argues that to say 'a unicorn has a single horn' tells me what a unicorn is (a determining predicate), but to say 'unicorns exist' says nothing about unicorns or what they are
Kant's own example is of a hundred thalers (a currency of his day)
He says that a hundred real thalers is exactly the same number of coins as a hundred possible thalers - the description is the same
The existence of the thalers is not something that can be defined by logic - it is defined by the experience of having them, therefore a priori arguments do not work
Kant's approach is to say that thinkers who put forward ontological arguments are treating existence in completely the wrong way
Strengths
Kant is right to argue that existence needs synthetic verification - 'God exists' is not an analytic statement because it does not hold the truth needed to verify within the statement - you have to look for evidence of existence, all statements about things existing are synthetic and need external evidence
Existence is not a real predicate because it does not add anything new to the description of a concept - eg I can describe a tiger as having stripes, claws, sharp teeth etc, but adding 'the tiger exists' does not add anything to my understanding
A definition of a concept does not bring it into existence - if we can think of things existing, then we can also think of them not existing
Weaknesses
A priori ontological arguments use reason only, not synthetic evidence - if you follow the premises, you have to come to the logical conclusion that God exists. Descartes argues that just as a triangle must have three sides and a mountain must have a valley, existence cannot be separated from God
The definition of God includes the predicate of existence - existence is part of what it means to be the greatest conceivable being (Anselm) or a supremely perfect being (Descartes)
God is logically necessary - Anselm's second formulation showed that it is greater to be necessary than contingent - a logically necessary being cannot not exist, so must exist
A priori and a posteriori arguments
A posteriori arguments are more persuasive
A posteriori arguments rely on empiricism, senses and observation which everyone can experience and verify - eg everyone can observe that the eye has a purpose to see or that there is a chain of causes and effects
A posteriori arguments use external (synthetic) evidence which leads to a probable conclusion - new evidence could alter or enhance the conclusion and it allows for a variety of approaches and is not so dogmatic.
John Wisdom
's parable illustrates this - two explorers witness the same evidence of a clearing in a jungle but reach different conclusions about whether or not there is a gardener - a posteriori arguments allow for this ambiguous evidence from the world about God
A posteriori arguments start from what is known, from the evidence available to everyone in the world, and then reach a conclusion about what is unknown - this is a more reasonable approach, how can we start with a concept like God, which we don't know?
A priori arguments are more persuasive
A priori arguments rely only on reason and logic so do not need to use the senses, which as Plato and Descartes claimed can deceive or lead to errors
A priori arguments are more persuasive because the premises have to lead to the conclusion - once we have agreed that the premises are valid, the conclusion must follow and cannot be denied. Ontological arguments use this formula: if you agree with the logic of the premises, you have to agree with the conclusion - this is more persuasive than a posteriori, probable conclusions where there is no certainty
Concepts can be defined a priori and do not rely on empirical evidence that can be interpreted in different ways - eg Anselm's ontological argument defines the concept of God in a way that everyone including non-believers could agree with