Knowledge and Belief • People can believe things that aren’t true. • For you to know something, it must be true and you must believe it. • Beliefs can be true or false. • Beliefs can accidentally be true, but it isn’t knowledge. Types of Knowledge • Analytic – true by definition – “Squares have 4 sides”. • Synthetic – not analytic, true or false in the way the word is – “Ripe tomatoes are red”. • A priori – doesn’t require sense experience to know – “all bachelors are unmarried”. • A posteriori – can be established through sense experience – “Snow is white”. All Analytic propositions are known a priori.
This doesn’t mean that all a priori propositions are analytic. The main question is “Are all synthetic propositions a posteriori? ” i. e; do we have some knowledge that doesn’t come from sense experience? It is this question that forms the debate between rationalism and empiricism. Rationalism vs. Empiricism • Main dividing questions are: “What are the sources of knowledge? ”, “How do we acquire it? ”, “How do we get concepts? ”. • Rationalism gives an important role to reason. • Empiricism gives an important role to the senses. • Why can’t we use both in acquiring knowledge? Rationalism.
• Rationalism claims that we can have synthetic a priori knowledge of the external world. Empiricism denies this. • Rationalists argue that it’s possible for us to know some synthetic propositions about the world outside our own minds, e. g. Maths and morality. Empiricists argue that it is not. • Both rationalists and empiricists accept that we naturally have certain thoughts and feelings inside our minds. Empiricism • An advantage of empiricism is that it allows us to quickly see how we ascertain our knowledge – through our senses by perceiving how the world is, which is a causal process – it requires no mental reasoning.
• Empiricists also claim that this is how we acquire our concepts – through our senses. • Once we understand the acquired concepts, we gain analytic knowledge. If we have knowledge that doesn’t come from sense experience – how do we get this knowledge? Rationalists argue that we either gain this knowledge from ‘rational intuition’ or ‘insight’, which allows us to gain this knowledge intellectually, or we just know these truths innately as part of our rational nature. Rationalists may also argue that some, or even all of our concepts are innate of come from rational insight. Do All Ideas Derive From Sense Experience?
John Locke – Mind as a ‘Tabula Rasa’ • Locke argues that all ideas derive from sense experience. • He says that the mind at birth is a ‘tabula rasa’ – a blank slate that gets filled up with ideas from the senses. • He refutes the claim of ‘innate ideas’. • Ideas can either be part of a proposition: “He had the idea that it would be fun to take the day off”; or they can be concepts: “the idea of yellow”. • Locke says that all our concepts derive from sense experience, and that we have no knowledge prior to sense experience. From Locke’s definition of ‘innate idea’, it follows that everyone with a mind should have the same ideas.
However, there is no truth that every person (including people lacking reasoning skills) can assent and agree to. So perhaps, with Locke’s definition, innate ideas are ones that we known as soon as we gain the use of reason. Locke refutes this, saying that we aren’t lacking reason but the knowledge of ideas. For example, a child can’t know that “4 + 5 = 9” until the child can count up to 9 and has the idea of equality. It is the same thing as knowing that an apple is not a stick – it’s not a development of reason, just the gaining of knowledge of ideas.
So therefore, if we must first acquire the concepts involved (through sense experience), the proposition cannot be innate, as no proposition is innate unless the concepts used are innate. Locke argues that the mind has no concepts from birth, and so no truths or concepts can be innate. A Different definition of ‘innate idea’ • Locke’s definition and argument against innate ideas hasn’t been criticized • People who believe in innate ideas don’t accept Locke’s definition • Nativists maintain the view that innate ideas are those which cannot be gained from experience
• Nativists tend to argue on how concepts or knowledge can’t be acquired from sense experience • Because we don’t know all concepts from birth, there is some point when we become aware of our concepts • Rationalists argue that experience triggers our awareness of our innate concepts. Experience as a ‘Trigger’ • Children begin to use certain ideas at certain time, and their capacities develop, so why can’t their concepts and knowledge also develop? • Children begin to use certain ideas at certain times • Experience still plays a role – a child must be exposed to the relevant stimuli for the knowledge to emerge, e. g.language.
• An idea is innate if it cannot be derived or justified by sense experience. Empiricists on Arguing Concepts John Locke 1. The senses let in ideas 2. These ideas furnish an ‘empty cabinet’ 3. The mind grows familiar with these ideas and they’re lodged in one’s memory 4. The mind then abstracts them, and learns general names for them 5. The mind then has ideas and the language by which it can describe them • However, what does it mean to ‘let in ideas’? • We contrast ideas with sensations, e. g. the sensation of yellow isn’t the same as the concept of yellow • Locke fails to make this distinction David Hume
• Hume believes that we are directly aware of ‘perceptions’ • Perceptions are then divided into ‘impressions’ and ‘ideas’ • Both Locke and Hume divide impressions into ‘impressions of sensation’ and ‘impressions of reflection’ • Impressions of sensation come from our sense data and that which we directly perceive • Impressions of reflection derive from the experience of our mind, such as feeling emotions. • Hume says that ideas are ‘faint copies’ of impressions • Therefore, there are ideas of sensation (e. g. the idea of red) and ideas of reflection (e. g. the feeling of sadness, happiness) • Concepts are a type of idea.
• Hume’s theory of how we acquire ideas (from copying them from impressions) is a theory of how we acquire concepts) • Locke and Hume both have slightly different versions of how we acquire ideas with which we can think • We start with experiences of the physical world which we get from sense data and experiences of our mind • For Locke, this gives us ideas once we employ our memory to reflect on these experiences • According to Locke, this makes it sound that the remembered experiences are the ideas with which we think • Hume corrects this, and says that we remember and think with the copies of the sensory impressions.
Simple and complex concepts • A complex idea is just an idea made up of several different ideas, e. g. a complex idea (a dog) is made up of simple ideas like shape, colour and smell. • This complex idea has a complex impression • We can therefore form complex ideas by abstraction. • As an objection, rationalism raises the question of where do non-empirical ideas come from? • Empiricism is appealing, as we seem to intuitively trust our senses and it easily answers such questions. • However, there are complex ideas that correspond to nothing from our sense experience, e. g. unicorns or God. • So do all ideas derive from sense experience?
• Empiricists argue that these complex ideas are made up from simple ideas, which are copies of impressions (e. g. a unicorn is the simple concepts of a horse, a horn, and the colour white, and combined together they give us a unicorn) • Hume and Locke argue that when creating complex ideas, one can only work with the materials that our impressions provide – simple ideas • Complex ideas are no more than altering or abstracting these simple ideas • Therefore, empiricists answer this rationalist objection So Are There Innate Concepts?
• What would an empiricists’ analysis of complex concepts like self, causality, substance, etc.be? • These concepts must either be innate, or reached using a priori reasoning • Hume accepts that these complex concepts cannot be derived from experience • However, he states that each of these concepts has no application • These concepts are confused, and we should always use concepts that can be derived from experience • For example, we don’t experience our ‘self’, we experience a changing array of thoughts and feelings. • To come up with the idea of ‘self’, we’ve confused similarity with identity • We do the same with the idea of a physical object • A physical object exists independently of experience, existing in 3d space.
• But can experience show us something that exists independently of experience? • If I look at a desk, look away, and then look back again, the desk must have existed when I wasn’t looking at it. • I can’t know that my experience was of the same desk, only that the experiences are similar • When coming up with the concept of a physical object that exists independently of experience, I confuse similarity with identity. • Hume concludes that these concepts are incoherent confusions • This can be objected though • This makes most of our common-sense understand and analysis of the world incorrect – we know that our concepts are coherent.
• Empiricism now seems to challenging to accept, as it makes our concepts ‘illusory’. • The fact that we cannot derive the aforementioned from experience shows that they are innate • Empiricists therefore have a flawed argument – explaining our most abstract concepts is an argument that these concepts are not derived from experience. • Does this therefore mean that they’re innate or arrived at through rational intuition? • One reason to think they’re innate is that children use these concepts before they develop rational intuition.
• Rationalists therefore argue that experience is the trigger for the concept Does all knowledge about what exists rest on sense experience? Hume’s Fork • We can have knowledge of two sorts of things: ‘Relations between ideas’, and ‘matters of fact’ • Relations of ideas are propositions like ‘all sons have fathers’ • Hume argue that all a priori knowledge must be analytic, and all knowledge of synthetic propositions must be a posteriori • Anything that is not true by definition (‘matters of fact’) must be learned through the senses • Hume’s ‘matters of fact’ are essentially analytic truths.
Matters of Fact • Hume says that the foundation of knowledge of matters of fact is what we experience here and now, or what we can remember • All our knowledge that goes beyond the aforementioned rests on casual inference • For example, if I receive a letter from a friend with a French postcard on it, I’ll believe that my friend is in France. • I know this because I infer from post mark to place • I think that where something is posted causes it to have a postmark from that place. • If the letter was posted by my friend, I believe that he is in France. • I ‘know’ this because I rely on past experiences.
• I don’t work out what causes what by thinking about it • It is only our experience of effects and causes that brings us to infer what cause has what effect. • Hume denies that this is ‘proof’ • He says that knowledge of matters of fact, beyond what we’re experience here and now relies on induction and reasoning about probability. Induction and Deduction • The terms relate to a type of argument • Inductive 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.
• A Deductive argument is an argument whose conclusion is logically entailed by its premises • If the premises are true, the conclusion cannot be false • E. g. Premise 1: Socrates is a man; Premise 2: All men are mortal; Conclusion: Socrates is mortal. Using a priori intuition and demonstration to establish claims of what exists • Rationalists argue against Hume, saying that some claims about what exists can be grounded on a priori intuition.
• A priori demonstration, or deduction, is deduction that uses a priori premises • Rational intuition is the view that you can discover the truth of a claim by thinking about it Descartes • Descartes says that we can establish the existence of the mind, the physical world and God through a priori reasoning.
• He attacks sense experience, and how they can deceive us • We can’t tell if we’re being deceived by an evil demon through our senses, as what we are experiencing will be false • We can establish that we think, and therefore we exist, even if our senses do deceive us (as we don’t need our senses to know our mind exists) • This conclusion of thinking and doubting that we exist was gotten to by pure reasoning. • He also establishes that the mind can exist from the body.
• Descartes says we don’t know what causes these experiences • It could be an evil demon, God, or the physics world exists exactly how we perceive it. • If it was God, it would mean he was a deceiver as we have a very strong tendency to trust our senses • If it was a demon, God must have created this demon to deceive us, and because God is perfect by definition, this would mean God isn’t a deceiver, and so he can’t have made a demon – so there must be some kind of a real world • Through a priori intuition and reasoning, Descartes says that the external world must exist, because God exists, and he would not deceive us.
Conceptual Schemes and Their Philosophical Implications • Humans don’t all have the same concepts • There are two distinguishable elements to our experience: the data of the senses, and how this data’s interpreted by our concepts • By the latter, it implies that different people would impose different conceptual scheme if they have different concepts. • Conceptual relativism claims that because our conceptual scheme affect how people experience and understand reality, people with different conceptual schemes have different realities. An Implication: Conceptual relativism.
• We assume people have different ‘realities’ because we can’t translate their to ours • It assumes language ‘constructs’ reality to say reality is relative to our conceptual schemes • It would mean that reality is dependant on language, which isn’t true – we express our realities by language • A proposition in one conceptual scheme can be true without needing to be express in another set of scheme. • This means that there isn’t one set of scheme with how the world works • An objection is that people argue that the relation between experience anc conceptual schemes doesn’t make sense.
• Benjamin Whorf says that languages organize our experience of the world • This is like trying to organize a wardrobe itself and not the clothes in it • If a conceptual scheme organizes our experience, then our experience must be comprised of individual experiences • Conceptual scheme all have a set of experiences in common • We can pick out individual experiences like smelling a flower, feeling cold, etc. • Any conceptual scheme with these sorts of experiences will end up similar to our own, despite the concepts one hold and their language, and so translation between two different conceptual schemes will be possible.
• There may be small parts that can’t be translated, but this only leads to a very mild form of conceptual relativism. • We can’t necessarily combine conceptual scheme • An example is that we can have more or less colours in our vocabulary, and so can describe things in different ways. • The Greeks thought that there was only one colour – bronze, and that everything else was a different shade of bronze. • This doesn’t mean they saw everything in what we call ‘bronze’, it’s just how they described their experiences. • We can therefore only state things depending on the concepts we have.