1. L ECTURE 14: H UME ’ S R ADICAL E MPIRICISM

2. T ODAY ’ S L ECTURE In Today’s Lecture we will: 1.Recap our investigation into empiricist theories of knowledge 2.Briefly consider the problem of correspondence and Berkeley’s arguments against Locke’s theory of knowledge 3.Become introduced to the radical empiricism of David Hume 4.Critique and discuss Hume’s theory of knowledge and its implications on philosophy, metaphysics, & science.

3. R ESPONSES TO L OCKE

4. Locke’s Theory of Knowledge: All ideas (knowledge) comes from experience There are two forms of experience: Sensation (Outer) Reflection (Inner) All ideas are either from inner experience or outer experience There are no innate ideas, only innate faculties Experience SensationReflection Simple Ideas Complex Ideas Passive Active

5. Locke’s Theory of Knowledge Water itself Idea of the water The idea of the water corresponds to a real object MindReality

6. Epistemological dualism Inner Experience External Experience Water itself Idea of the water 1. 2.3.

7. R ESPONSES TO L OCKE The Problem of Correspondence Representational theories of perception maintain that everything we know is an idea in the mind that represents or corresponds to something outside of the mind Problem: How do we know if our ideas of an object accurately correspond to the object itself? All we have are ideas of objects We cannot have knowledge of anything that is not an idea Therefore, we cannot have knowledge of an object apart from an idea Therefore, we can never know if our ideas of water correspond to the water itself

8. Berkeley’s Response to Locke Water itself Idea of the water Berkeley argues that there is nothing more to an object than the qualities we perceive (the idea) We can never perceive the causes of things we perceive MindReality

9. Epistemological dualism Inner Experience External Experience Water itself Idea of the water 1. 2.3.

10. Berkeley’s theory of Reality Mind Idea of the water Ideas exist only in minds All things are ideas Therefore, all things exist only in minds

11. R ESPONSES TO L OCKE Berkeley’s Arguments for Idealism Esse est Percepti (To be is to be perceived) All objects (chair, water etc.) are sensible things A sensible thing is a collection of qualities that we perceive There is nothing more to any object than the sum of its qualities All sensible qualities exist only as ideas Therefore, objects only exist in minds Nothing exists independently of a perceiving mind The idea of a substratum (substance/matter) that is the cause of ideas, but free from qualities is incoherent. This is because we cannot: a)have an idea of something that cannot be experienced b)perceive the causes of what we perceive c)conceive of anything without qualities.

12. R ESPONSES TO L OCKE In Summary Locke’s theory of knowledge faces the following problems: 1.The problem of correspondence We can never be sure whether our ideas of an object correspond to the object itself There is an epistemological gap between our knowledge of an object and the object itself 2.Berkeley’s Criticisms We are never able to have an idea of anything that cannot be perceived The idea of physical substance is incoherent All that we can be sure of is that minds and ideas in minds exist We can never have access to the object itself

13. D AVID H UME

14. David Hume: o Lived 1711-1776 o One of the ‘great’ British empiricists o Advocated a Radical form of empiricism o Made important contributions to Metaphysics, Epistemology, Philosophy of Religion o Hume’s radical empiricism has important consequences for the investigation into philosophy, religion and science

15. D AVID H UME David Hume’s Phenomenalism All knowledge is derived from and limited to appearances Appearances are presented to us in our perceptions Perceptions can be divided between 1.Impressions Lively, Vivid Sensations 2.Ideas Pale impressions / copies All ideas are derived from impressions All the mind possesses is a collection of perceptions

16. D AVID H UME David Hume’s Phenomenalism There are two bases of knowledge: 1.Relations of Ideas Ideas that are intuitively or demonstratively certain E.g. Geometry, Arithmatic, Logic, Algebra etc. 2.Matters of Fact Ideas that pertain to the world E.g. The sun will rise tomorrow, This chair is red, etc.

17. D AVID H UME What’s so radical about Hume’s radical empiricism? Aristotle, Aquinas, & Locke all argue that we can have certain knowledge For example; This is a chair The chair is really red The chair exists But! Hume argues that these thinkers fail to follow empiricism to its rational conclusions Hume: If all knowledge comes from perception Either Our ideas are certain but not informative Or Our ideas are informative but not certain

18. I MPLICATIONS OF H UME ’ S R ADICAL E MPIRICISM

19. I MPLICATIONS The limits of knowledge: 1.Relations of Ideas Ideas that are intuitively or demonstratively certain E.g. Geometry, Arithmetic, Logic, Algebra etc. Relations of ideas can give us certain knowledge They don’t teach us anything new They have no bearing or relevance on reality For Example: Socrates is a man All men are mortal Therefore Socrates is mortal Doesn’t teach us anything new Has no relevance upon reality Certain

20. I MPLICATIONS The limits of knowledge: 2. Matters of Fact Ideas that pertain to the world E.g. The sun will rise tomorrow, This chair is red, etc. Matters of fact can teach us new things about the world But they can never be certain It is always possible that they can be rendered false Entirely dependent on perceptions For Example: Earth days are now 1.26 nanoseconds faster Teaches us something new about the world Cannot be certain

21. I MPLICATIONS Hume’s attack on the principle of substance: It is natural to believe : Descartes/Locke: There exists both mental and physical substance Berkeley: Physical substance does not exist but mental substance (mind) does Hume’s challenge: Do we ever perceive substance? No. Therefore, we cannot rationally claim that substance exists Hume: Sense impressions have priority over ideas There are no ideas without sense impressions Hume: Sense impressions have priority over ideas There are no ideas without sense impressions

22. I MPLICATIONS Hume’s attack on the principle of the ‘Self’: It is natural to believe : Berkeley/Locke/Descartes: That there is a thinking thing, a ‘self’, ego, etc. Hume’s challenge: Do we ever perceive a self? No. Only many perceptions Therefore, we cannot rationally claim that the self exists Hume: Sense impressions have priority over ideas There are no ideas without sense impressions Hume: Sense impressions have priority over ideas There are no ideas without sense impressions

23. I MPLICATIONS Hume’s attack on the principle of ‘Causality’: It is natural to believe : That every event has a cause / Causal connection Hume’s challenge: Do we ever perceive a necessary connection? No. We perceive that A occurs, then B occurs; but we don’t perceive the necessary connection where A causes B All we perceive is contiguity (things close together) and succession; We never perceive causation! Therefore, we cannot rationally claim that every event has a cause Hume: Sense impressions have priority over ideas There are no ideas without sense impressions Hume: Sense impressions have priority over ideas There are no ideas without sense impressions

24. I MPLICATIONS Examples against causation: At age 1 a child begins to: o Feed themselves o Walk by themselves o Learns simple words o Receives their Measles, Mumps, Rubella vaccinations For Example: A child (A) receives their MMR vaccinations, then (B) begins to feed themselves A  B But! A did not cause B.

25. I MPLICATIONS Implications for modern scientists: 1.All scientific theories must be limited to what can be observed or observed in principle 2.All scientific claims are either i.Relations of ideas E.g. All mammals are warm blooded Or ii.Matters of fact E.g. The Earth day is now 1.26 nanoseconds faster 3.Scientific claims/’laws’/theories cannot be certain (only likely or unlikely) It is always possible that a scientific claim can be proved false because of future observations Popper: Scientific theories must be falsifiable (Principle of Falsifiability) For example: Theories of the subconscious cannot be observed or falsified; therefore they are not scientific Popper: Scientific theories must be falsifiable (Principle of Falsifiability) For example: Theories of the subconscious cannot be observed or falsified; therefore they are not scientific

26. S UMMARY Summary: Empirical (all) knowledge can only be either: Necessarily true but not informative Or Informative but not certain All ideas are derived from perceptions Any idea we have that is NOT derived from perceptions should be abandoned When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume, of divinity or school metaphysics, for instance; let us ask, “Does it contain any experimental reasoning concerning matter of fact and existence?” No. Commit it then to the flames: for it can contain nothing but sophistry and illusion. (David Hume, Textbook, p.225) When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume, of divinity or school metaphysics, for instance; let us ask, “Does it contain any experimental reasoning concerning matter of fact and existence?” No. Commit it then to the flames: for it can contain nothing but sophistry and illusion. (David Hume, Textbook, p.225)