Knowledge Rationalisation and Empricism

Where does propositional knowledge come from?

What do rationalists believe?

That reason is the ultimate source of knowledge, and therefore we can have some knowledge innately a priori and use intuition and deduction to discover this knowledge.

What do empiricists believe?

That all knowledge comes from a posteriori experience, we have no innate knowledge.

What important philosophers were rationalists / believed in innate ideas?

Plato, Descartes and Leibniz.

Which important philosophers were empiricists / believed we have no innate ideas?

Hume, Locke and Russell.

What type of truth do philosophers disagree about whether it is possible or impossible?

Synthetic a prioris that are necessary truths a priori but are not true by definition and instead proven true by the external world.

What are some examples of synthetic a prioris?

Murder is wrong, stealing is wrong, all triangles have three sides.

How do rationalist innatists believe we rediscover our innate ideas?

Either a priori through deduction and reason or a posteriori through a teacher re-awakening the knowledge.

Why did Plato believe that we have innate ideas?

Despite the world of senses having many inconsistencies we have permanent unchanging ultimate truths that cannot come from this changing world.

Where did Plato believe we got our innate ideas from?

The world of Forms, a perfect world consisting of universal ideas which are given to us before we are born.

How did Plato ‘prove’ that we have innate ideas?

In the Meno Socrates questions a slave body who has never been taught geometry about dividing squares, never specifically telling him a fact, to ‘prove’ that he had this knowledge innately.

Why does Plato’s ‘proof’ of innate ideas fail?

Through his questioning, ruling out certain options, Socrates indirectly teaches the boy geometry; he did not have the knowledge innately but was instead learned via trial and error.

Why did Plato believe we must all have universal concepts that come from the World of Forms?

We see particular instances of beauty for example in nature or on people, labelling them both as beautiful despite them being very different. We must therefore have a universal concept of beauty as we would not otherwise link these concepts together, and these ideas must come from the World of Forms as they are too consistent to come from our world.

Where did Plato believe that our innate universal ideas are stored?

Our souls.

What are the three classic features of innatism first proposed by Plato?

Innate ideas are in us but we may not be aware, we can recognise these ideas through reason. These innate ideas provide timeless truths that always have and always will be true regardless of time or place.

What is the main problem with Plato’s innatism specifically?

As he believed that all knowledge is implanted into the soul before birth and then remembered by a posteriori experiences, then Greeks would have had the same amount of knowledge as us, e.g. knowing the universal concept of slavery being wrong. Greeks should have heard the word slavery and remembered the innate idea of its dangers but did not and therefore we cannot have all knowledge innately.

Why does Plato’s innatism seem implausible?

He believed that all ideas were innate and therefore the Greeks would have had the same amount of knowledge as us, e.g. how to make and use a smartphone, which seems ridiculous and implausible.

What did Descartes mean by rational intuitions?

An innate ability to know clear and distinct truths a priori.

What is Descartes best proof of rational intuitions?

The cogito, knowing that we exist as either the author of our thoughts or receiver of thoughts a priori.

How does Descartes believe we verify rational intuitions (the innate ideas we are born with)?

Through deductions and reasoning a priori.

How can our rational intuitions be certain?

If they are clear and distinct concepts in our mind that we can fully understand distinct from any other concepts.

How can clear and distinct ideas be certain?

In the Cogito Descartes establishes the clear and distinct idea that he must exist, which must be true, and therefore the principle of trusting when we have a clear and distinct idea must be applied to all other cases.

Does Descartes believe that God is a rational intuition (innate idea)?

Yes, he tries to demonstrate this through his Trademark argument and Ontological argument.

Descartes Trademark argument (an example of deduction being used to demonstrate rational intuitions)

We are imperfect beings that have the idea of a perfect, eternal, immutable omni God that we cannot be the cause of the idea of as we are imperfect and the cause of something must be greater than the effect and therefore a perfect God must exist that was able to cause our idea of a perfect God.

Descartes Ontological argument (an example of deduction being used to demonstrate rational intuitions)

He has the idea of God, a supremely perfect being, and since a supremely perfect being does not lack any perfections and existence is a perfection God must exist.

Problems with Descartes’ Ontological argument

Descartes assumes that existence is a perfection, and therefore a necessary part of our concept of God, with the same certainty that a triangle must necessarily have three sides when this is not true, existence is not a predicate so is not necessary and therefore God’s existence is not a rational intution.

Descartes Cogito argument to demonstrate the rational intuition that we exist standard form

P1. I am either the author of my thoughts, or I am deceived into thinking that I am the author of my thoughts by something like an evil demon.

P2. If I am the author of my thoughts, then I exist as the author.

P3. If I am deceived into thinking that i am the author, then I am the object of deception.

P4. If I am the object of deception, then I exist as the object of deception.

C. Either way, “I am, I exist” so long as I have thoughts.

Descartes argument to show that we can trust clear and distinct ideas standard form

P1. In the first item of knowledge (Cogito) there is a clear and distinct perception of what I am asserting (that I exist).

P2. If clarity and distinctness do not guarantee truth then I cannot know I exist.

P3. I do know I exist.

C. Therefore ‘as a general rule… whatever I perceive very clearly and distinctly is true’.

What ideas are clear and distinct according to Descartes?

Ideas that are ‘present and accessible to the attentive mind’, almost self evident / verifying and able to be understood fully and clearly as an independent concept.

What is the name for John Locke’s belief about innate ideas?

Tabula rasa, blank slate. We are born with no knowledge.

What is Locke’s first objection to innate ideas?

They are uneccessary, following Ockham’s razor we should just gain things from experience without having to follow the extra step of remembering it via experience.

What is Locke’s second objection to innate ideas?

No ideas are universal, e.g. not everyone knows the law of non-contradiction, which means we cannot have innate ideas because we would have the same ideas if they were innate.

What is Locke’s third objection to innate ideas?

Surely we would be aware that we had innate ideas, surely this belief would be transparent?

What is Locke’s fourth objection to innate ideas?

How do we distinguish innate ideas from learned ideas?

What is Locke’s fifth and final objection to innate ideas?

Their existence weakly relies on an unproven supernatural god-like being.

What did John Locke believe we have innately?

An ability to learn and categorise ideas into simple or complex combinations.

Which two ways does Locke believe our ideas come from?

Sensation and reflection through the ‘internal operations of our minds’ e.g. thinking.

What type of knowledge did Leibniz believe we have innately?

Universal necessary truths such as triangles having three sides or the law of non-contradiction (although not by this name) as well as innate dispositions to form certain ideas.

How does Leibniz reply to Locke’s objection to innate ideas 1 - no universal ideas?

Just because ideas are not universal does not mean innate ideas do not exist, they could be innate for some people but not for others.

How does Leibniz reply to Locke’s objection to innate ideas 2 - the law of non-contradiction?

Although we may not know the law of non-contradiction by name we know for example it cannot be raining and not raining. Therefore we do have universal ideas which could be innate, just not by the same name as philosophers.

How does Leibniz reply to Locke’s objection to innate ideas 3 - transparency and awareness?

Just because we are not aware of something does not mean it cannot exist, innate ideas could subconsciously be in us like there are background sounds we process subconsciously.

How does Leibniz reply to Locke’s objection to innate ideas 4 - distinguishing innate concepts from learned ones?

Only necessary analytic truths are innate, so we can clearly distinguish between these and synthetic a posterioris.

Why does Leibniz argue that only universal necessary truths are innate?

Because humans are not advanced enough to know everything innately even though it is possible, only God knows everything innately.

What does Leibniz’s block of marble analogy show?

The mind is like a block of marble; the veins inside the block are our analytically true innate ideas and we have to chip away via experience to access this knowledge.

Why does Leibniz believe that that our mental content is not exclusively from experience?

He argues we have many petites perceptions, small unconscious mental states that demonstrate the mind is active even when we are not aware of ideas.

How does Leibniz argue our mind processes ideas?

Actively rather than passively, the mind actively organises experience in a structure that cannot have been provided via experience.

Bishop Berkeley’s argument that ‘proves’ God.

P1. As physical objects are mind-dependent there are three possible causes of my perceptions, ideas, my mind, or another mind.
P2. Ideas do not cause anything, they just are.
P3. If physical objects depended on my mind I would be able to control my perceptions.
P4. I cannot control my perceptions or my sensations.
C1. Therefore physical objects do not depend on my mind so must depend on another mind.
C2. That mind must be God and therefore God exists.