1. A tree falls in a forest but there is no one to hear it, does it make a sound?

2. An Introduction to Perception Epistemology is the theory of knowledge i.e. how do we know what is real or not real? We will focus on three theories of perception: – Direct Realism – Indirect (or Representative) Realism – Idealism. How we become aware of, identify or know something.

3. Imagine you met an alien who does not perceive the frequencies of light as we do. Instead the alien perceives a whole set of higher ones, such as ultra violet and beyond. The alien represents these waves in a range of colours just as we do. In pairs discuss: Who sees the true colours of the world: humans or aliens? But if neither does, does that mean that no colours are the real colours?

4. Thinking questions…… Do you think your favourite food tastes the same to a dog as it does to you? Do you think dog food tastes the same to you as to a dog? Who has a truer perception of the world: dogs or humans?

5. Realism vs Idealism Central question in debate on perception: How much of what we perceive is really a feature of the external world, and how much is a feature of our minds? 2 theories on this: – Realism: At least some of what we perceive is a feature of the external world, & exists independently of our minds. – Idealism: None of what we perceive is a feature of the external world: it is all just a feature of our minds.

6. REALNOT REALDON’T KNOW Numbers i.e. 5,6,7 Your reflection in a mirror Colours i.e. blue Smells Morality Electrons Scientific laws e.g. law of gravity Ghosts Matter i.e. what makes up the material universe Beauty Consider whether the object or topic is real or not. For this exercise take ‘real’ to mean ‘has an existence independent of minds – human or otherwise’.

7. Two forms of realism Direct Realism (aka ‘common-sense’ or ‘naïve’ realism): – We see things in the external world immediately and directly. – We don’t see them by seeing anything else. What does this mean? All objects are composed of matter: they occupy space, have properties such as smell, texture, size etc. We perceive these properties directly. Therefore the senses provide us with direct awareness of the external world! These objects continue to observe the laws of physics & retain their properties whether or not there is present anyone to observe them doing so. A tree falls in a forest, but no one is there to witness it. Does it make a sound according to direct realism?

8. The naïve realist theory may be characterized as the acceptance of the following five beliefs:beliefs There exists a world of material objects.material Some statements about these objects can be known to be true through sense-experience.sense-experience These objects exist not only when they are being perceived but also when they are not perceived. The objects of perception are largely perception-independent.perception-independent These objects are also able to retain properties of the types we perceive them as having, even when they are not being perceived. Their properties are perception-independent. By means of our senses, we perceive the world directly, and pretty much as it is. In the main, our claims to have knowledge of it are justified."knowledge

9. Indirect realism (aka representative realism): – We see things in the external world indirectly, by seeing mental representations of them. – When I look at a table, I see the appearance of it – a mental image, which represents it to me. – Philosophers call this mental image a sense datum (sense data). – Indirect realists say that we see physical objects by seeing their sense data (just as we might see a celebrity by seeing their image on a TV screen). Two forms of realism For the indirect realist, there is a distinction between the way the object appears to the observer and the object as it is in reality. Sense data or sensations are a representation or image of the world. It’s as if we had pictures in our minds which represent to us the real world outside of our minds.

10. In simpler terms…. Both claim that the physical world exists independently of perceivers and that the world is as science says it is. But….. Direct realism claims that what we perceive is really the external world. Whereas…. Indirect realism claims that what we immediately or directly perceive are sense-data, rather than the physical world itself, which can only be perceived indirectly. Crux of the matter: they disagree over whether we perceive the properties of matter directly and as they are.

11. Activity Draw a diagram, using words/lines/ pictures etc., to illustrate the difference between the direct and indirect realists’ theories of how we perceive physical objects.

12. Three illusions 1.The thumb and the moon: – If you hold your thumb up to the moon, your thumb looks bigger – even though it obviously isn’t. 2.The rose under sodium light: – Under sodium street lamps, a red rose will look grey, even though it hasn’t changed colour. 3.The stick in water – If you half-submerge a straight stick in water, and look at it from the side, it looks bent, even though it isn’t.

13. How could someone use these 3 illusions to argue against direct realism? Set your argument out in ‘standard form’ Activity

14. The argument from illusion - 1 One way of stating this: P1.If direct realism is true, then the world must always be exactly the way it appears to us. P2.The 3 illusions show that the world isn’t always exactly the way it appears to us. C.So the 3 illusions show that direct realism is false.

15. The argument from illusion - 2 Another way of stating it: P1. When I look at a stick in water, I see something that is bent. P2. The bent thing cannot be the stick itself. IC.So it must be a mental image of the stick – a sense-datum. C. But this means I see the stick indirectly, by seeing its sense-datum – in which case direct realism is false.

16. Brainstorm the strengths and weaknesses of direct and indirect realism. Put down as many as you can – be speculative!

17. What do you see?

18. Read Bertrand Russell’s Chp 1 (pp 1 - 4). Answer the comprehension and evaluation questions.