John Locke. British Empiricism

Transcription

1 John Locke British Empiricism

2 Locke Biographical Notes: Locke is credited as the founder of the British "Common Sense" movement, later known as empiricism - he was also the founder of the modern political Liberalism movement, a medical doctor and a Professor of Philosophy at Oxford!

3 Locke s Arguments against Descartes: 1. Locke rejects deduction as the only source of reliable knowledge Deduction can t tell us anything new the truths contained in deduction are only truths by definition in a deductive argument, the conclusion cannot contain anything that is not already contained in the premises.) Later we will see that Locke argues that if used properly, induction can be reliable

4 Locke s Arguments against Descartes: 2. Locke rejects both Plato s and Descartes concepts of universal innate ideas - even if universal knowledge exists => then it could be explained through universal experience common experiences of what it is like to be human but universal knowledge does not exist ideas not known to children & idiots (p.173) innateness requires us to know and not know simultaneously which is impossible (especially since Descartes maintained that the mind was transparent to itself)

5 Locke s Theory of Knowledge Locke Redefines Descartes Goal For Locke there are limits to human understanding and it is important to find out what they are - fairly certain knowledge is the most reasonable goal not absolute certainty. The empiricists were looking for a construct of knowledge within the framework of sense data whose aim was to develop a probable hypothesis about the world. This knowledge is based on claims that always admit of the possibility that one might be wrong a margin of error may be assigned and the less probable the error, the more probable the claim it may approach certainty but never achieve certainty. At best, one might claim to know something without having, at the time, any good reason to doubt it.

6 Locke s Theory of Knowledge Locke introduces the tabula rasa (blank slate) picture of the mind written on by experience - he argues that we are like a blank slate when born - we have the potential to know things but nothing is written on the board yet. This is consistent with the examples above - children begin knowing nothing beyond certain physical needs and "idiots" seem to have the inability to retain anything - that is to learn.

7 Locke s Theory of Knowledge Locke argues for causal theory of perception & representational picture of the mind. Locke has an atomic or perhaps more accurately a corpuscular theory of ideas. There is, that is to say, an analogy between the way atoms or corpuscles combine into complexes to form physical objects and the way ideas combine. Ideas are either simple or complex. We cannot create simple ideas, we can only get them from experience. In this respect the mind is passive. Once the mind has a store of simple ideas, it can combine them into complex ideas of a variety of kinds. In this respect the mind is active. Thus, Locke subscribes to a version of the empiricist axiom that there is nothing in the intellect that was not previously in the senses where the senses are broadened to include reflection. (Stanford Encyclopedia of Philosophy)

8 Locke s Theory of Knowledge An object existing in the physical world Causes me to perceive it as it comes in contact with my eyes Which then gives rise to a simple idea in my mind I form an idea of the dog which represents the dog in the world Which then may give rise to a complex relation of ideas (The object I perceive is a dog it is a Schnauzer and Schnauzers can be high maintenance and expensive dogs to keep)

9 Locke s Theory of Knowledge Experience data is the source of all knowledge & Induction can yield reliable information. We learn by making generalizations from (sensory) experience and testing those hypotheses based on the perceptions we receive from the world. This is the foundation principle of modern science. UK geologists evaluating a core sample.

10 Locke s argument for independent existence of the material world P1) there is a difference between primary qualities and secondary qualities SP1) Primary qualities those qualities which pertain to the object itself (objective) weight, mass, figure, extension SP2)Secondary qualities those qualities which depend on the perceiver as much as the perceived object (subjective) color, sound, texture, taste, smell P2) if there is a difference between primary qualities and secondary qualities then there must be a distinction between the perception and the object perceived (between the idea of the object and the object itself) P3) if there is a distinction between the perception and the object perceived then the object must exist independently of the perceiver the object cannot merely be a subjective idea of the perceiver & entirely dependent on the perceiver. C) Objects must exist independently of our perception

11 Locke s argument for independent existence of the material world Six reasons for why we should trust the senses as evidence of the independent existence of the material world: 1. senses produce pleasure and help avoid pain. 2. if sense is missing then so is corresponding idea e.g. people who are blind from birth can have no sense of color. 3. we have no choice in act of perceiving we cannot just wish things into or out of existence. 4. there is a difference between the sensation and the memory of sensation 5. there is an agreement between the senses 6. sensation works to preserve us dreaming gets us into trouble

12 Locke on Substance: Hence, when we talk or think of any particular sort of corporeal substances, as horse, stone, &c., though the idea we have of either of them be but the complication or collection of those several simple ideas of sensible qualities which we used to find united in the thing called horse or stone ; yet because we cannot conceive how they should subsist alone, nor one in another, we suppose them existing in, and supported by some common subject; which support we denote by the name substance, though it be certain we have no clear or distinct idea of that thing we suppose a support. (p. 186)