Lecture 8: Idealism

1. Lecture 8: Idealism

2. In today’s class we will: Recap the investigation we began in the previous lecture into the Mind-Body problem Briefly outline two possible ways of resolving the mind-body problem by using Monistic theories of reality Investigate in further detail Berkeley’s theory of reality; Idealism Discuss the implications and validity of Berkeley’s theory of reality Today’s Class

3. In our previous lecture...

4. In our previous lecture we began investigating the mind-body problem: If Mind and Brain (Body) are composed of two distinct substances, how do we explain their causal interaction? How does something non-physical and non-spatial causally interact with something completely different to itself? Recap ?

5. Possible solutions

6. A Dualist View of Reality Mental Physical Experience of Seeing something Red Brain Activity in Response to Stimuli Thought About the Cow in the Road Physical and Behavioural Responses Taste of Ice Cream Neurones and Chemicals in the Brain Unbridgeable Gap Possible Solutions

7. Materialistic Monism Everything in reality is composed of material (physical) substance What are these things? Physical Experience of Seeing something Red Thought About the Cow in the Road Taste of Ice Cream Physical and Behavioural Responses Brain Activity in Response to Stimuli Neurones and Chemicals in the Brain Possible Solutions

8. Berkeley’s Idealism

9. Idealistic Monism Everything in reality is composed of Mind or Ideas Experience of Seeing something Red Thought About the Cow in the Road Taste of Ice Cream Physical and Behavioural Responses Brain Activity in Response to Stimuli Neurones and Chemicals in the Brain Mind/Ideas Berkeley’s Idealism

10. Berkeley’s Idealism Descartes’ View of Reality Ice Water Steam Solid Melting Evaporating Qualities/Properties Physical Substance Wax H2O

11. Berkeley’s Idealism Locke’s View of Reality Relative and Dependent on a Perceiver Color Taste Sound Texture Secondary qualities Size Location Movement Shape Objective and Independent of Perceiver Primary qualities Physical Substance The Water Itself

12. Locke’s View of Reality Secondary Sound Color Taste Texture Temperature Primary Location Shape Size Movement Idea of the water Mind Matter Water itself

13. Locke’s Theory of Knowledge Idea of the water Water itself Reality Mind The idea of the water corresponds to a real object

14. Berkeley’s Response to Locke Idea of the water Water itself Reality Mind 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

15. Berkeley’s theory of Reality Secondary Sound Color Taste Texture Temperature Primary Location Shape Size Movement Idea of the water Ideas exist only in minds All things are ideas Therefore, all things exist only in minds Mind

16. Berkeley’s Arguments for Idealism (1) EsseestPercepti(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 Berkeley’s Idealism The idea of a substratum (substance/matter) that is the cause of ideas, but free from qualities is incoherent. This is because we cannot: have an idea of something that cannot be experienced perceive the causes of what we perceive conceive of anything without qualities.

17. Berkeley’s Response Secondary Sound Color Taste Texture Temperature Primary Location Shape Size Movement Idea of the water Mind Matter Sound Waves Light Waves Water itself

18. Berkeley’s Arguments for Idealism (2) • Primary and Secondary qualities cannot be separated • We cannot conceive of objects without texture, color etc. • The existence of primary qualities also depend on being perceived by a mind • Primary qualities are also relative • Size, location, movement, shape, etc. also change from person to person Berkeley’s Idealism Berkeley still maintains that the world and all of its objects are real But the reality of these objects is dependent on their being perceived by a mind

19. Berkeley’s Idealism Locke’s View of Reality Color Taste Sound Texture Relative and Dependent on a Perceiver Secondary qualities Size Location Movement Shape Primary qualities Physical Substance The Water Itself There is no room in Berkeley’s model for the existence of things without substance

20. How can we be sure that what we see is real? • For Berkeley something is real if it is being perceived • If it is not being perceived we cannot be sure of its existence • However, we cannot create or choose what to see in reality • The world, and its objects are always there • We receive sense impressions passively (empiricism) • We can be sure of the objective existence of reality because God perceives everything • Objects exist in God’s mind, and not just ours! Berkeley’s Idealism The sensible world exists if, and only if, it is perceived by a mind The sensible world exists unperceived by human minds Therefore, the sensible world must be perceived by a nonhuman mind

21. How we can be sure that things have objective existence Secondary Sound Color Taste Texture Temperature Primary Location Shape Size Movement Idea of the water Mind

22. How we can be sure that things have objective existence Secondary Sound Color Taste Texture Temperature Primary Location Shape Size Movement Idea of the water Mind

23. Berkeley maintains that: • Reality is composed of one thing: Ideas/Minds/Mental stuff • To be is to be perceived (EsseestPercipti) • Objects only exist as ideas in the mind • An object is nothing more than the sum of its sensible properties • We can be sure of the objective existence of objects because God perceives everything • Given the alternatives, this is the most suitable theory of reality • This theory of reality also provides a proof for God’s existence and the existence of a world not perceived by humans • His theory overcomes the problem of dualism in both the philosophy of mind and the theory of knowledge Summary