- There are different types of knowledge: aquaintance knowledge (I know Oxford well), ability knowledge (I know how to ride a bike) and propositional knowledge (I know that eagles are birds). Theories of knowledge discussed here are about propositional knowledge.
- Knowledge is not the same as belief. Beliefs can be mistaken (I believe that flamingos are grey), but no one can know what is false.
- Knowledge is not the same as true belief, either. True beliefs may not be justified, but can be believed without evidence (I was kissed today because my horoscope said so). To be knowledge, a belief must be justified.
- Rationalism claims that we can have synthetic a priori knowledge of how things are outside the mind.
- Empiricism denies this. It claims that all a priori knowledge is only of analytic propositions.
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Do all ideas derive from sense experience?
- Locke argues that the mind at birth is a 'tabula rasa' (blank slate) - there are no innate ideas, which Locke defines as ideas present in the mind from birth.
- Locke argues that there is no truth that everyone, including children and idiots, assents to - so no truth is innate.
- Rationalists define innate ideas as ideas (concepts or propositions) whose content can't be gained from experience, but which are triggered by experience.
- Locke and Hume argue that all concepts are copies of impressions; complex concepts are created out of simple concepts by combining and abstracting from them.
- One argument for innate concepts is to challenge the empiricist to show how a particular complex or abstract concept, for example PHYSICAL OBJECT, is supposed to be derived from experience. If it cannot be, and it is used by children, then this is a reason to think it is innate.
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Are all claims about what exists ultimately gro...
...unded in and justified by sense experience?
- Hume argues that all a priori knowledge is of relations to ideas, and so analytic. All knowledge of synthetic propositions, matters of fact, is a posteriori. It depends either on present experience or causal inference, which relies on past experience.
- Our knowledge of matters of fact that relies on induction can only be probable, never proven.
- Some rationalists, for example, Descartes, try to show that we can use a priori intuition and deductive argument to demonstrate what exists.
- The core of the idea of rational intuition is that you can 'see' the truth of a claim just by thinking about it.
- Descartes argues that sense experience on its own cannot establish what exists - how can we know that all sense experience is not a deception, caused by an evil demon?
- He argues that he cannot doubt his own existence, and that the mind can exist without the body.
- Descartes argues for the existence of the physical world by first arguing for the existence of God. From God not being a deceiver, it follows that our sense experience - in general - can't be completely mistaken, so the physical world exists.
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Conceptual schemes and their philosophical impl...
- Thinkers who defend the idea of conceptual schemes often argue that there are two distinguishable elements to our experience - the data of the senses and then the interpretation of these data by a set of concepts.
- Some argue that human beings have formulated different conceptual schemes which are not translatable into each other. From the same sense experience, they form different views of the world.
- Because we must use concepts to formulate truths, we can argue that truths are relative to conceptual schemes. Or more accurately, some truths can only be stated in certain conceptual schemes and not others, and there is no one conceptual scheme which we can use to state all truths.
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