Knowledge from Reason

• Analytic truths are truths in virtue of the meaning of the words
• An example of an analytic truth would be that a bachelor is an unmarried man
• Synthetic truths are true in virtue of how the world is
• An example of a synthetic truth would be that grass is green
• Innatism is the believe that we are born with some knowledge already (a priori knowledge)
• Rationalism is the belief that we aquire knowledge through intuition and deduction (a posteriori knowledge)
• A priori knowledge is knowledge that can be acquired without experience of the external world
• A posteriori knowledge is knowledge that can only be acquired from experience of the external world
• Intuition is the ability to know something is true just by thinking about it
• Deduction is the method of using propositions to find out other propositions
• Empiricism says all a priori knowledge are analytic truths ( no synthetics are a priori knowledge)
• Rationalism says that not all a priori knowledge is of analytic truths ( there's at least one synthetic truth that can be known as a priori)
• The three waves of doubt are Illusions, dreaming and deception
• Wave of doubt illusion can be used through a pencil that appears crooked, we know that a pencil is straight
• Wave of doubt dreaming there are ideas that are common in reality and dreams such as that 1+1= 2 so can this be doubted?
• Last wave of doubt, deception, an evil demon is controlling everything I know, so I don't know what's true or false known as global scepticism
• Cogito ergo sum means I doubt, therefore I think, therefore I am
• Cogito ergo sum proves that since i'm able to doubt what I know, I must therefore exist because I have to exist to be able to be doubted
• The trademark argument:

  1. I have the concept of God
  2. My concept of God is something infinite and perfect
  3. I am a finite and imperfect being
  4. The cause of me thinking God is perfect has to be as real as me believing that he is perfect
  5. So the cause of my idea of God must be an infinite and perfect being
  6. So God exists
• Hume's Fork is used to challenge Descartes' arguments for rationalism, where there's only 2 kinds of knowledge: Matters of Facts and relation of ideas
• Relation of ideas cannot be denied without a contradiction, they're analytic a priori truths
• Matters of fact have no logical contradiction in it being false, they're synthetic a posteriori truths
• Contingent truths are truths that may not be the same in every world
• An example of a contingent truth would be that Lyon is the capital of France
• Leibniz argues that necessary truths are all innate knowledge
• Necessary truths are truths that must be possible in every world
• An example of a necessary truth would be that 2+2=4
• Problem of innatism - Has to be universal and Locke argues that children and idiots don't possess such knowledge
• The argument with Innate knowledge is that Empiricism says we don't have innate knowledge and Innatism says we do
• Plato:Meno is a test for innate knowledge on a boy slave for whether he has innate knowledge of geometry, he's never been taught geometry yet understands the questions he's asked