Reason as a source of knowledge

• There are two types of knowledge: a priori and a posteriori
• Something is a priori if you can check its truth without needing sense experience
• Strawson said "you can see [a prori knowledge] is true just lying on your couch"
• a posteriori knowledge is knowledge that is only known to be true through the experiences we have of the world, using the senses
• When applied to propositions, the a priori/a posteriori distinction is about how to check knowledge
• An a posteriori concept is one derived from experience
• an a priori concept is one that cannot be derived from experience
• There is a distinction between propositions. They can be analytic and sythetic
• A proposition is analytic if it is true or false just in virtue of the meanings of the words
• Kant describes an an analytic proposition as one where the 'predicate is contained within or belongs to the subject'
• predicate


  quality
• analytic truths tell us nothing of the world itself
• analytic propositions are tautologies
• a proposition is synthetic if it is not analytic
• a proposition is synthetic if it is true/false in reference to the way the world is
• synthesis is about new information
• some truths are described by philosophers as being necessarily true; it being a contradiction to deny them
• necessary truths are "true in all possible worlds"
• contingent truths are truths that just happen to be the case
• A priori knowledge

  a type of knowledge where the justification for knowing it comes simply from thought.
• A posteriori knowledge

  empirical, experience-based knowledge
• analytic truth


   a statement true in virtue of logic
• Synthetic truths are true both because of what they mean and because of the way the world is
• a necessary truth is a truth that must be
• All propositions known a priori are analytic
• Synthetic truths are true both because of what they mean and because of the way the world is, whereas analytic truths are true in virtue of meaning alone.
• only analytic propostions are a priori
• all synthetic propositions are a posteriori
• empiriscists say that all knowledge of synthetic propsoitions is a posteriori and all a priori knowledge is of analytic propsitions
• rationalists deny empiriscism - they believe that there is some a priori knowledge of synthetic propositions. Either because this knowledge is innat or because it is gained through the use of internal reasoning rather sensory experience
• rationalists argue that the a priori knowedge that we possess cannot be gained any other way
• Plato believed that discovering the most ideal version(ie the form of it) of something is useful as it allows us to form clear definitions of what it is
• Who believes that we possess some form of innate knowledge?

  rationalists
• who believes tha we gain knowledge from the senses

  empiriscists
• rationalist definition of a priori knowledge


  they are analytical tautologies that are true in themselves - they give us no information about the way that the world works
• a priori


  truths independent of experience checked through reasoning
• sense impressions are what is inferred from the word, ideas derived from the senses via immediate experience
• Leibniz

  Necessary(general) truths are innate as we know them a priori
• Locke


  If innate knowledge exists it would be universal and conscious
• Leibniz

  Innate knowledge is similar to the etchings in marble. The mind is predisposed to certain ideas