Reason as a Source of Knowledge
This is the third topic in Epistemology. Instead of focusing on senses to gain knowledge, we are now looking at reason.
We'll be looking at Innatism, Descartes' Intuition and Deduction Theses and Scepticism.
Plato's Rationalism
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The Argument from Recollection is one of Plato’s arguments for the existence of the world of forms and also the existence of the soul.
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Plato points out that we somehow do have knowledge of perfect, eternal and unchanging concepts. These include concepts like perfect beauty and justice. We also have perfect mathematical concepts and geometric concepts.
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We have never experienced perfect beauty, justice or a perfect circle. So, we must have gained this knowledge a priori.
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(Meno) Socrates proved that an uneducated slave boy could be prompted by a series of questions and some shapes drawn in the sand to figure out how to solve a geometry question. The slave boy must therefore have been born with geometric concepts. Plato's answer is that we must have somehow gained these concepts before we were born. Our soul existed in a realm where there were perfect forms. In the world of forms there are perfect mathematical forms and perfect forms like the form of beauty and the form of justice.
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We are born with a dim recollection of the forms because our soul apprehends them before becoming trapped in this world of appearances. Anamnesis is the process of re-remembering these forms through a posteriori sense experience.
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Plato concluded that the source of knowledge must therefore be a priori, making him a rationalist
If you're a fan of doom metal, listen to this song by Emma Ruth Rundle and Thou which features information on Plato and the analogy of the cave!
Leibniz & Necessary Truths
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Leibniz argues that people can have knowledge even if they can’t express it. We can tell by the way children behave in the world that they must ‘unconsciously’ assent to such necessary truths as ‘something cannot be and not be at the same time’.
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Innate knowledge could require some sort of unlocking by interaction with experience in order to be consciously known.
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Necessary Truths: innate propositions are necessary, as they cannot fail to be true. However, we only ever experience contingent things. All the objects in our experience depend on something else for their existence.
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Experience of contingent beings does not involve necessity, so cannot be used to infer necessary propositions.
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If knowledge of necessary propositions cannot be gained from experience then they must be gained through the unlocking of our innate potential to know them by experience.
“The mind is capable not merely of knowing [necessary truths], but also of finding them within itself. If all it had was the mere capacity to receive those items of knowledge… it would not be the source of necessary truths… For it cannot be denied that the senses are inadequate to show their necessity”
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Let us suppose the mind to be, as we say, a tabula rasa, void of all characters, without any ideas. How comes it to be furnished? Whence comes it by that vast store, which the busy and boundless fancy of man has painted on it, with an almost endless variety? When has it all the materials of reason and knowledge? To this I answer, in one word, from experience.
Response: John Locke
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Locke believed that Innatism is false and that the mind is a Tabula Rasa at birth.
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Reason 1: If a proposition were innate then it would be universally assented to, meaning everyone would be know it because everyone would be born with it. Universal assent must be a necessary condition of innate knowledge.
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Reason 2: Even if there was a proposition that was universally assented to, that wouldn’t necessarily make it innate. For example, there might be something universal about experience in general which produced the knowledge.
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All our ideas come from either sensation or reflection. Sensation is when our senses experience objects in the external world. Reflection occurs when we experience the ‘internal operations of our minds’.
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Locke’s account here aims to show how all concepts and knowledge, from simple to complex, can be explained as coming from experience in some way.
Integration: universal assent is a necessary but not a sufficient criteria for innate knowledge. There is no knowledge which satisfies the necessary condition for innateness of universal assent and thus there is no innate knowledge.
Response: David Hume
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Everything our mind directly experiences is a perception.
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Perceptions from the external world are impressions.
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Perceptions from inside our mind are ideas. Ideas are usually less vivid.
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Ideas can be simple or complex. A simple idea is one which cannot be broken down any further, e.g greenness. Complex ideas are combinations of simple ideas. A green apple is a complex idea made from the combination of the simple ideas of greenness, the taste of an apple, the texture etc.
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We are able to form abstract concepts such as beauty or justice or God by abstracting from experience.
Intuition and Deduction Thesis
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Intuition: The ability to know something is true just by thinking about it .
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Deduction: A method of deriving true propositions from other true propositions (using reason)
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Clear Idea: An idea you can grasp without confusion or ambiguity (e.g., triangle = three sides).
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Distinct Idea: An idea that is unmistakably separate from all others with no potential for overlap (e.g., triangle ≠ square).
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We can gain synthetic knowledge through a priori means by intuition and deduction.
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Intuition is when the rational mind apprehends something (whether true or false) with immediacy, without any process of reasoning.
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Descartes claims there is a ‘natural light’ of the mind which makes us recognise certain truths because we cannot doubt them.
Descartes' Cogito
One thing Descartes can be unequivocally sure of is that he exists:
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I doubt
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Therefore I think
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Therefore I am
You can be sceptical about almost everything, but Descartes cannot doubt that he exists.
Because we are able to doubt our own existence, that means we must exist in the first place.
We have to look at this bit now, because it is an example of something known with immediacy, but this will come up again in the Limits of Knowledge section.
dubito, ergo cogito, ergo sum
Fun fact: I tried to remove the background of this image and it removed Descartes eyes as well. Now we have this ^
Descartes' Deduction of the Existence of God
The Trademark Argument
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P1. I exist (intuition as we can know it with immediacy)
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P2. I have an idea of a supremely perfect being in my mind. (intuition)
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P3. The causal adequacy principle is true. (intuition).
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C1. I am not causally adequate to create the idea of a supremely perfect being, only a supremely perfect being is. (deduction).
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C2. A supremely perfect being exists (deduction)
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Only God is causally adequate for the idea of God in my mind.
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Criticism: Hume: the concept of God is not innate but can be created by human minds. Take human qualities like goodness and imagine what they were like without limitations by removing all imperfections and applying them to God. Goodness becomes Omnibenevolence.
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Criticism: We can use Hume's Fork to criticise this argument. Descartes' definition of God makes God existing an analytic truth. You cannot contradict an analytic truth and a contradiction cannot be coherently conceived. But ‘God does not exist’ can be coherently conceived Therefore, ‘God does not exist’ is not a contradiction and Descartes has not proved God's existence.
Descartes' Deduction of the Existence of the External World
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P1. I have a clear and distinct idea of a physical substance (something that has extension).
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P2. My perceptions are involuntary and cannot originate from my own mind, which I control voluntarily.
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C1. Therefore, the origin of my perceptions must be one of three possibilities: physical objects, God, or I am being deceived.
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P3. The source cannot be God, because it would imply God is deceiving me. But deception implies imperfection, and God is perfect. Nor would God allow me to not trust my own perceptions by being perceived.
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P4. Descartes has already established that God exists (above).
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C2. By process of elimination, the cause of my perceptions must be physical objects. Therefore, an external world exists.
Fun fact: Where Descartes lived it was very cold in winters. To stay warm, he sometimes slept in closed rooms heated by an open stove or oven.
Problem: The Cartesian Circle
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Descartes claims that anything he perceives clearly and distinctly must be true.
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Descartes says that we could be being deceived, even about clear and distinct ideas. So he asks: how can he know his clear and distinct ideas are reliable
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Descartes proves that God exists and is perfect. A perfect God would not deceive, so we can trust that clear and distinct ideas are true.
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Descartes uses clear and distinct ideas to prove God exists, but then uses God’s existence to guarantee the truth of clear and distinct ideas. This is circular.
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So the problem is: we are using clear and distinct ideas to defend clear and distinct ideas.
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Descartes could respond: Clear and distinct ideas don’t rely on God, but God guarantees their reliability. They are self-evident and immediately known whenever I perceive them clearly