Rationalism

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  • Rationalism
    • Plato - appearance and reality
      • How are we to discover what (e.g.) beauty is? Our senses reveal beautiful things. But the these things are subject to change. A beautiful thing can lose its beauty.  Beauty itself cannot be destroyed. So, beauty can’t belong to the world open to the senses. Beauty belongs in a different realm to the realm of appearances and it is reason that gives us access to it.
      • The Allegory of the Cave
        • 1. The sun = the form of the good
          • 2. objects outside the cave = the forms
            • 3. reflections of objects outside the cave = mathematical truths
              • 4. puppets in the cave = physical objects
                • 5. shadows and echoes = Illusions, pictures etc.
      • The Forms
        • (2) Reason gives us knowledge of the Forms (universals)– the essences of things.  Before we were born, our souls lived in the world of Forms. In this embodied life, our knowledge of the forms is buried and must be unearthed by exercising reason – doing philosophy.
        • (1) The Forms cannot be detected with the senses but only with reason.
        • (3) Plato gives four arguments for this:
          • 1. THE CONTEXT ARGUMENT :  (whether a painting is beautiful or not varies with the context but its sensible features do not. So, the Forms can’t be sensible.)
            • Something F in one context may not be F in another.  Picture A may be beautiful in relation to picture B but not in relation to picture C.  Since the painting can be beautiful and not beautiful, it can't provide us with a definition of what is beautiful.
              • Whatever beauty is, it can't fail to be beautiful. Since any thing that we find beautiful could fail to be beautiful in another context, we can't simply collect beautiful things together and hope that they will share some simple sensory property that we can identify as the property of being beautiful.
                • We have to look for the Form of the beautiful or beauty: the thing that makes beautiful things beautiful. It is the essence of beauty. But it cannot be detected by the senses, only reason. Why? Take a beautiful painting. In one context beautiful, in another not. But nothing about how the painting appears changes. So, we're looking in the wrong place if we look for beauty amongst perceptible properties.
          • 2. THE KNOWLEDGE/CHANGE ARGUMENT:   the Forms are unchanging. Sensory experience reveals a changing world. So, the Forms are non-sensible
            • Badgers change. They change their age, weight, number of hairs, location, etc.  But knowledge doesn’t.  Knowledge is of truths - if you know something, it can’t be(come) false.The objects of knowledge are therefore unchanging, timeless things.Knowledge is possible.So, there must be unchanging things that we can have knowledge of - the Forms.
          • 3. THE IMPERFECTION ARGUMENT: No perfect circle can exist in the sensible world, only approximations. No actual circle can be infinitely thin and perfectly curved
            • We know many truths about circles, e.g. Area = ?r2 and there are 360o in a circle. But no circles we see or draw are perfect. So, our knowledge must be of some perfect circle - the Form of the circle.
          • 4. ONE OVER MANY: If x and y are both F, then there must be something, F, that they have in common
            • What makes something the kind of thing it is? What makes two things members of the same kind? They both “participate in” the Form of the badger. The “one over many” argument: if x and y are badgers, there must be something – the Form of the badger – that they have in common.  These days, philosophers talk of universals instead of forms.
              • The Form of a badger is not present where the badgers are but exists in a different realm. The universal badger exists in each and every badger. It is quite unlike an ordinary object, as an object can be only in one place at any one time. Objects are a type of particular. But the universal exists in many places at once,  it is repeated throughout its instantiations, and hence is called a universal. Fundamentally, however, we’re talking about the same thing – an entity that makes a particular belong to a kind or makes it the kind of thing it is.
      • The Slave Boy
        • By asking a series of questions, Socrates gets the slave boy to work out the area of two squares. This shows that the boy knew all along the relevant principles of geometry. He has innate knowledge, gained from when his soul existed in the world of forms.
    • Descartes
      • (1) Doubt
        • The senses are fallible and could be deceived. It is only through reason that I can be certain of anything:1st: My own existence.2nd: God’s existence.3rd: God’s benevolence.4th: My capacity for clear and distinct ideas. Science is not concerned with the sensible properties of things. It is concerned with quantifiable properties. Reason is required to work out the mathematical structure of the universe: e.g. the laws of physics.  The senses inform us of a changing world. Reason grasps the underlying structure of the world. (Think of the wax example.)
      • (2) The Wax Example
        • (1) When solid the wax properties are - Sight: bright yellowSmell: flowersTaste: pollenSound: dull thudFeel: solid
        • (2) when melted the wax properties are - Sight: dull yellowSmell: noneTaste: noneSound: noneFeel: soft, malleable
        • (3) All that remains constant is occupancy of space by matter: extension.
        • (4) Only reason can grasp the unchanging nature of the wax.
        • EXTENSION: Descartes concludes that extension in space is the essential nature of the wax. Given that the property of extension is studied by geometry and geometry is purely a priori, it follows that we can have a priori knowledge of the wax. This applies to all physical objects and is rationalism in its most extreme form.
          • Descartes also said that the melted wax can adopt and infinite amount of different steps. As the concept of infinity is grouped by the mind not the senses, he claimed that we could know the wax through an inhibition of the mind.
      • (3) Innate knowledge and number
        • I know it innately. I have an understanding of the ‘concept’ of wax that does not rely on any sense experience of the wax itself. Therefore I know what wax really is, despite the evidence of the senses.  Descartes says it is extension in space. And this can be expressed mathematically.  Given that the property of extension is studied by geometry and geometry is purely a priori, it follows that we can have a priori knowledge of the wax.
          • A priori: knowledge that is known independently of experience. For example, once I understand the statement ‘no object can be red and green all over at the same time’, I recognise that it must be true. There is no need to check through observation or experimentation. Innate knowledge will be known a priori.
      • (4) Cogito Ergo Sum
        • I think therefore I am
        • “So after considering everything very thoroughly, I must finally conclude that this proposition, I am, exist is necessarily true whenever it is put forward by me or conceived in my mind.” Meditation II.
        • Descartes’ first certainty is established through the application of reason alone. He has put into doubt all beliefs arrived at by the senses through the use of the ‘evil demon’. His certain existence results from his awareness of himself as the subject of his thoughts.
      • (5) God
        • I noticed certain laws which God has so established in nature, and of which he has implanted such notions in our minds, that after adequate reflection we cannot doubt that they are exactly observed in everything which exists or occurs in the world.
        • But although deep, as it stands, this conviction that the universe is intrinsically intelligible to reason is only an assumption.However, Descartes is certain there is a necessary symmetry between his innate understanding and the real structure of the universe – so that he is able to understand how the universe ought to be:
    • Knowledge, truths, arguments and statements.
      • (6) INDUCTION AND DEDUCTION
        • An INDUCTIVE argument is where the conclusion is not logically entailed by its premises, but supported by them. If the premises are true, the conclusion is likely to be true. The French letter example is an example of inductive reasoning.
          • Here is an example: Socrates was Greek. (premise) 2. Most Greeks eat fish. (premise) 3. Socrates ate fish. (conclusion)
        • A DEDUCTIVE argument is an argument in which it is impossible for the premises to be true but the conclusion false.Thus, the conclusion follows necessarily from the premises. In this way, it is supposed to be a definitive proof of the truth of the claim (conclusion).  E.g.  Premise 1: Socrates is a man; Premise 2: All men are mortal; Conclusion: Socrates is mortal.
      • (1) People can BELIEVE things that aren't true. For you to KNOW something, it must be true AND you mist believe it. Beliefs can be true or false. they can also be accidentally true, but that ISN'T knowledge.
      • (4) All ANALYTICAL knowledge is A PRIORI but not all A PRIORI knowledge is ANALYTICAL
      • (5) This produces most important question: ARE ALL SYNTHETIC PROPOSITIONS A POSTERIORI? this means do we have some knowledge that doesn't come from sense experience?
        • Hume says we cannot have a priori synthetic - empiricist Descartes says we can have a priori synthetic, so we know before experience but its not true by definition
    • INTRO
      • (1) The fundamental source of knowledge is reason. Knowledge is a matter of gaining certainty. If p is certain, it must be true: the justification rules out any possibility that it is false.  Experience cannot deliver certainty. Only reason can.
      • (2) Plato: our senses reveal a world of appearances. Things in this world are subject to change. Only reason can go behind this world to the unchanging world of things as they really are.
      • (3) Descartes: our senses are fallible and limited. Things can be other than they seem and experience alone cannot ever prove that how the world seems is how it is.
      • (4) We have innate ideas and innate knowledge. Coming to know is either discovering what we already know or the result of reason using those materials to make new discoveries.
      • (5) Only through reason can we learn about God, Morality, Logic, Metaphysics, Aesthetics, Geometry, Mathematics etc.
    • Spinoza and Leibniz
      • Leibniz
        • •The innate rational capacity to grasp ideas purely intellectually and work with them is crucial in science. As Leibniz explains:   …a corpuscle hundreds of thousands times smaller than any bit of dust which flies through the air, together with other corpuscles of the same subtlety, can be dealt with by reason as easily as can a ball by the hand of a player.
        • The senses cannot give us knowledge of necessary truths. Experience can tell me how things are now:e.g. this piece of metal conducts electricity. Many experiences can tell us how things are on many occasions: e.g.piece of metal 1 conducted electricity on 1/2/07piece of metal 2 conducted electricity on 2/2/07piece of metal 3 conducted electricity on 3/2/07… and so on
          • But only on finitely many occasions. But we want to know general or universal necessary truths: do all bits of metals conduct electricity? We can never verify by experience whether it is part of the essence of being a metal that it conducts electricity because we cannot check every bit of metal.
        • So we can only discover general, necessary truths through reason.
        • TRUTHS
          • NECESSARY TRUTHS: Are truths which are true in any circumstances, under any condition & Liebniez - "Possible in any world."- A proposition that could have never been false
            • E.G. 2+2=4 / Snow is white / The sun is yellow / All red things are coloured
          • CONTINGENT TRUTHS: A proposition that is not necessarily true, that could be both false and true.- True is some worlds but not others.
            • All buses are red All swans are white All coloured things are red
        • INTROSPECTION:  Could be both E or R. - Look within yourself to find information - Descartes, Cogito ergo sum = Rationalism - Locke, Formation of ideas: Primary Concepts = Complex concepts + E & Berkely (Sensations and Reflection)
        • TAUTOLOGICAL: - True by definition (Basically analytical) 2x2=4 / Snow is white / Bachelors are unmarried men
        • All contingent truths happen because of god's goodness.
      • Spinoza
        • All truths are necessary and contingency is an illusion
      • PROBLEMS
        • Both beliefs based on God - no experience/scientific reasoning behind it.

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