• There are different types of knowledge: acquaintance, ability and propositional knowledge. Theories of knowledge discussed here are about propositional knowledge.
• Knowledge is not the same as belief. Beliefs can be mistaken, 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. 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.
Do all ideas derive from sense experience?
• Locke argues that the mind at birth is a ‘tabula rasa’ – 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 idiots and children, 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 derived from sense experience, from impressions of sensation or reflection.
• They claim that simple concepts are copies of impressions; complex concepts are created out of simple concepts by combining and abstracting them.
• One argument for innate concepts is to challenge the empiricist to show how a particular complex or abstract concepts, for example, a 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.
Are all claims about what exists ultimately grounded in and justified by sense experience?
• Hume argues that all a priori knowledge is of relations of ideas, and so analytic. All knowledge of synthetic propositions, matters of fact, is a posteriori. It depends either on present experience or causal